UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

(Rule 14a-101)

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

Filed by the Registrant  ☒                             Filed by a Party other than the Registrant  ☐

Check the appropriate box:

ENANTA PHARMACEUTICALS, INC.

(Name of Registrant as Specified in Its Charter)

(Name of Person(s) Filing Proxy Statement, if Other Than the Registrant)

Payment of filing fee (Check the appropriate box):

ENANTA PHARMACEUTICALS, INC.

500 Arsenal Street

Watertown, Massachusetts 02472

(617) 607-0800

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS TO BE HELD FEBRUARY 28, 2019

The 2019 Annual Meeting of Stockholders of Enanta Pharmaceuticals, Inc. (“Enanta”), a Delaware corporation, will be held at The Charles Hotel, 1 Bennett Street, Cambridge, Massachusetts 02138, at 4:30 p.m. local time on Thursday, February 28, 2019, for the following purposes:

The record date for the 2019 Annual Meeting is January 4, 2019. Accordingly, only stockholders of record at the close of business on that date may vote at the meeting or any adjournment thereof.

It is important that your shares be represented at the meeting. Therefore, whether or not you plan to attend the meeting, please complete your proxy and return it in the enclosed envelope, which requires no postage if mailed in the United States. If you attend the meeting and wish to vote in person, your proxy will not be used.

By order of the Board of Directors,

Nathaniel S. Gardiner

Secretary

January 18, 2019

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE

ANNUAL MEETING OF STOCKHOLDERS TO BE HELD ON FEBRUARY 28, 2019

This proxy statement and our Annual Report are available online at the “Investors – Annual Meeting Materials” section of our website at www.enanta.com. To obtain directions to The Charles Hotel in order to attend the annual meeting in person, please visit the “Investors – Annual Meeting Materials” section of our website at www.enanta.com or contact Investor Relations at (617) 607-0710.

TABLE OF CONTENTS

PROXY STATEMENT

INFORMATION CONCERNING SOLICITATION AND VOTING

We are soliciting proxies from our stockholders to vote at our 2019 Annual Meeting of Stockholders, or at any continuation, postponement or adjournment thereof, for the purposes discussed in this proxy statement. The annual meeting will be held at 4:30 p.m. local time on Thursday, February 28, 2019 at The Charles Hotel, 1 Bennett Street, Cambridge, Massachusetts 02138. For directions to The Charles Hotel in order to attend the annual meeting in person, please visit the “Investors – 2019 Annual Meeting Materials” section of our website at www.enanta.com or contact Investor Relations at (617) 607-0710.

The proxy materials, including this proxy statement and our 2018 annual report to stockholders, are being distributed and made available on the Internet at the “Investors – 2019 Annual Meeting Materials” section of our website at www.enanta.com on or about January 18, 2019.

This proxy statement contains important information for you to consider when deciding how to vote on the matters brought before the meeting. Please read it carefully.

All references in this proxy statement to a particular year, e.g. 2018, refer to our twelve-month fiscal year ended on September 30 of that year, e.g. September 30, 2018, unless the context indicates otherwise.

QUESTIONS AND ANSWERS ABOUT THE ANNUAL MEETING AND VOTING

Why did I receive these materials?

We are soliciting proxies for our annual meeting of stockholders to be held on Thursday, February 28, 2019. You are receiving a proxy statement because you owned shares of our common stock on January 4, 2019, the record date for the special meeting, and that ownership entitles you to vote at the meeting. By use of a proxy, you can vote whether or not you attend the meeting.

When and where is the Annual Meeting?

The annual meeting will be held at The Charles Hotel located at 1 Bennett Street, Cambridge, Massachusetts 02138 at 4:30 p.m. on Thursday, February 28, 2019, or at any future date and time following an adjournment or postponement of the meeting.

What proposals will be voted on at the Annual Meeting?

The five proposals to be considered and voted on at the annual meeting, as set forth in the accompanying Notice of Annual Meeting of Stockholders, are:

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As far as we know, the only matters to be brought before the annual meeting are those referred to in this proxy statement. If any additional matters are presented at the annual meeting, the persons named as your proxies may vote your shares in their discretion.

Do I have to attend the meeting to vote?

No. If you want to have your vote count at the meeting, but not actually attend the meeting in person, you may vote by granting a proxy or, for shares held in street name, by submitting voting instructions to your broker or nominee. The following summary outlines the various procedures for voting:

Stockholder of Record: Shares Registered in Your Name.

If on January 4, 2019 your shares were registered directly in your name with our transfer agent, then you are a stockholder “of record.” If you are a stockholder of record, you may vote in person at the annual meeting or by mail. Whether or not you plan to attend the meeting, we urge you to vote by proxy to ensure your vote is counted. You may still attend the meeting and vote in person if you have already voted by proxy. Voting in person will revoke your proxy. There are three ways to vote:

Beneficial Owner: Shares Registered in the Name of a Broker or Bank.

If on January 4, 2019 your shares were held not in your name, but rather in an account at a brokerage firm, bank, dealer, or other similar organization, then your shares are held in “street name” and you are the beneficial owner and not the record owner of the shares. If you are a beneficial owner of shares registered in the name of your broker, bank, or other agent, you should have received a proxy card and voting instructions with these proxy materials from that organization rather than from us. Please complete and mail that proxy card to ensure that your vote is counted. Alternatively, you may vote over the Internet, if instructed by your broker or bank that you may do so. To vote in person at the annual meeting, you must obtain a valid proxy from your broker, bank or other agent. Follow the instructions from your broker or bank included with these proxy materials or contact your broker or bank to request such a proxy form.

Who can vote at the Annual Meeting?

Only stockholders of record at the close of business on January 4, 2019, the record date, are entitled to notice of, and to vote at, the annual meeting or any adjournment or postponement of the meeting. On the record date, we had outstanding 19,435,128 shares of common stock, each of which is entitled to one vote upon each of the matters to be presented at the meeting.

See “Do I have to attend the meeting to vote” above for more information regarding voting.

What is the quorum requirement?

A quorum of stockholders is necessary to hold a valid meeting. A quorum will be present if at least a majority of the outstanding shares are represented by stockholders present at the meeting or present by proxy. On

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the record date, there were 19,435,128 shares outstanding and entitled to vote. Thus, 9,717,565 shares must be represented by stockholders present at the meeting in person or by proxy to have a quorum.

Your shares will be counted towards the quorum only if you submit a valid proxy (or one is submitted on your behalf by your broker, bank or other nominee) or if you vote in person at the meeting. Abstentions and broker non-votes will be counted towards the quorum requirement. If there is no quorum, a majority of the votes present at the meeting may adjourn the meeting to another date.

How are votes counted?

Votes will be counted by the inspector of election appointed for the meeting, who will separately count “For” and “Withhold” and, with respect to proposals other than the election of directors, “Against” votes, abstentions and broker non-votes. Abstentions and broker non-votes have no effect and will not be counted towards the vote total for any proposal.

If your shares are held by your broker in “street name”, you will need to obtain a proxy form from the institution that holds your shares and follow the instructions included on that form regarding how to instruct your broker to vote your shares. If you do not give instructions to your broker, your broker can vote your shares with respect to “discretionary” items, but not with respect to “non-discretionary” items. Discretionary items are proposals considered routine on which your broker may vote shares held in street name in the absence of your voting instructions. Non-discretionary items are matters such as mergers, stockholder proposals, executive compensation and elections of directors. On non-discretionary items for which you do not give your broker instructions, the shares will be treated as broker non-votes.

What if I return a proxy card but do not make specific choices?

If you return a signed and dated proxy card without marking any voting selections, your shares will be voted

Can I change my vote after submitting my proxy?

Yes. You can revoke your proxy at any time before the final vote at the meeting. If you are the record holder of your shares, you may revoke your proxy in any one of four ways:

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If your shares are held by your broker or bank as a nominee or agent, you should follow the instructions provided by your broker or bank.

What is the vote required for a proposal to pass?

How can I find out the results of the voting at the Annual Meeting?

Preliminary voting results will be announced at the annual meeting. Final voting results will be published in a Current Report on Form 8-K, or Form 8-K, that we expect to file with the Securities and Exchange Commission, or SEC, within four business days after the annual meeting. If final voting results are not available to us in time to file a Form 8-K within four business days after the annual meeting, we intend to file a Form 8-K to publish preliminary results and, within four business days after the final results are known to us, file an additional Form 8-K to publish the final results.

Who is paying for this proxy solicitation?

We will pay for the entire cost of soliciting proxies. In addition to mailing the proxy materials, our officers, directors and employees may also solicit proxies in person, by telephone, or by other means of communication. Officers, directors and employees will not be paid any additional compensation for soliciting proxies. We may also utilize the assistance of third parties in connection with our proxy solicitation efforts and we would compensate such third parties for their efforts.

Householding of Annual Meeting Materials

Some banks, brokers and other nominee record holders may be “householding” our proxy statements and annual reports. This means that only one copy of our proxy statement and annual report to stockholders may have been sent to multiple stockholders in your household. We will promptly deliver a separate copy of either

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document to you if you call or write us at our principal executive offices, 500 Arsenal Street, Watertown, Massachusetts 02472, Attn: Investor Relations, telephone: (617) 607-0710. In the future, if you want to receive separate copies of the proxy statement or annual report to stockholders, or if you are receiving multiple copies and would like to receive only one copy per household, you should contact your bank, broker, or other nominee record holder, or you may contact us at the above address and telephone number.

No Appraisal Rights

There are no appraisal rights associated with any of the proposals being considered at the annual meeting.

BENEFICIAL OWNERSHIP OF COMMON STOCK

The following table and footnotes set forth certain information regarding the beneficial ownership of our common stock as of December 1, 2018 by (i) persons known by us to be beneficial owners of more than 5% of our common stock, (ii) each of our current executive officers named in the Summary Compensation Table included in “Executive Compensation” below, (iii) our current directors and (iv) all our current executive officers and directors as a group. The percentage of shares beneficially owned is computed on the basis of 19,427,636 shares of our common stock outstanding as of December 1, 2018.

Beneficial ownership is determined in accordance with the rules and regulations of the SEC and includes voting or investment power with respect to our common stock. Shares of our common stock that a person has the right to acquire within 60 days of December 1, 2018 are deemed outstanding for purposes of computing the percentage ownership of the person holding such rights but are not deemed outstanding for purposes of computing the percentage ownership of any other person, except with respect to the percentage ownership of all directors and executive officers as a group. Except as otherwise indicated in the footnotes below, we believe the persons and entities in this table have sole voting and investing power with respect to all of the shares of our common stock beneficially owned by them, subject to community property laws, where applicable. Except as otherwise indicated in the footnotes below, the address of the beneficial owner is c/o Enanta Pharmaceuticals, Inc., 500 Arsenal Street, Watertown, MA 02472.

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Section 16(a) Beneficial Ownership Reporting Compliance

Our executive officers and directors and persons who own beneficially more than 10% of our equity securities are required under Section 16(a) of the Securities Exchange Act of 1934 to file reports of ownership and changes in their ownership of our securities with the SEC. They must also furnish copies of these reports to us. Based solely on a review of the copies of reports furnished to us and written representations that no other reports were required, we believe that for our 2018 fiscal year our executive officers, directors and 10% beneficial owners complied with all applicable Section 16(a) filing requirements, except that Drs. Carter, Golumbeski and Russell, Messrs. Buckley and Vance and Ms. Peterson each filed one late Form 4 on March 5, 2018 with respect to a grant of options on February 28, 2018.

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PROPOSAL 1

ELECTION OF DIRECTORS

Our Board of Directors has fixed the number of directors at seven. Under our charter, our Board is divided into three classes, with each class having as nearly as possible an equal number of directors. The term of one class expires, with their successors being subsequently elected to a three-year term, at each annual meeting of stockholders. At the 2019 annual meeting, the two nominees named in this proxy statement as Class III Directors will be elected to hold office for three years until their successors are elected and qualified. The Board has nominated Lesley Russell, MBChB, MRCP and Stephen Buckley, Jr. for re-election as Class III Directors at the upcoming annual meeting. Dr. Russell and Mr. Buckley are independent directors as defined by applicable Nasdaq Stock Market standards governing the independence of directors. Each nominee has consented to serve, if elected. If any nominee is unable to serve, proxies will be voted for any replacement candidate nominated by our Board of Directors.

Votes Required

Directors will be elected by a plurality of the votes cast by the stockholders entitled to vote on this proposal at the meeting. Broker non-votes and proxies marked to withhold authority with respect to one or more Class III directors will not be treated as votes cast for this purpose and, therefore, will not affect the outcome of the election.

Nominees for Director and Current Directors

The following table contains biographical information as of December 1, 2018 about the nominees for Class III Directors and current directors whose terms of office will continue after the annual meeting. The table includes information provided by the directors individually as to their age, current position, principal occupation and experience for the past five years, and the names of other publicly-held companies for which they currently serve as a director or have served as a director during the past five years.

Current SEC rules require us to discuss briefly the specific experience, qualifications, attributes or skills that led the Board to conclude that each director or nominee for director should serve on our Board of Directors. We have provided this discussion in a separate paragraph immediately below the biographical information provided for each director.

As you read the disclosure, please keep in mind that any specific qualification, attribute or skill that is attributed to one director should not necessarily imply that other directors do not possess that qualification, attribute or skill. Furthermore, this disclosure does not impose on any director any duties, obligations or liability that are greater than the duties, obligations, and liability imposed on each other member of the Board.

Because the discussion of the specific experience, qualifications, attributes or skills of a director is to be made each year in light of Enanta’s business and structure at that time, the content of this discussion may change for one or more directors in future years.

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Recommendation

We recommend a vote “FOR” each of our two Class III director nominees.

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PROPOSAL 2

2019 EQUITY INCENTIVE PLAN

We are asking stockholders to approve a new equity plan to replace the existing 2012 Equity Incentive Plan, which we refer to herein as the 2012 Equity Plan. The new 2019 Equity Incentive Plan, which we refer to herein as the 2019 Equity Plan, will provide 1,600,000 new shares of common stock for equity awards to our employees, directors and consultants, in addition to any shares still available, or that may hereafter become available through forfeitures of prior equity awards, under the 2012 Equity Plan and its predecessor, the 1995 Equity Incentive Plan. Approval of the 2019 Equity Plan will also terminate the so-called “evergreen provision”, which was a feature of our 2012 Equity Plan, that provided for automatic annual increases to the number of reserved shares. If Proposal 2 is approved by the requisite vote of stockholders, the Company intends to register subsequently the additional shares reserved for issuance under the 2019 Equity Incentive Plan by filing a registration statement on Form S-8.

Reasons for Adopting a New Plan and for Seeking Stockholder Approval

Equity Awards are a Key Part of our Compensation Program for Employees Generally

Our Compensation Committee believes that equity compensation has been, and will continue to be, a critical component of our compensation program because it develops a culture of ownership among our employees and aligns their interests with the interests of our stockholders. Unlike many companies, we have a practice of granting equity-based awards throughout our organization, believing that we will succeed if all our employees feel invested in us, our business and our future. From January 2013 to December 15, 2018, we have almost tripled our employee headcount (from 39 employees to 115). In 2019, we anticipate that we will continue to build our research and development team to support clinical development of our most advanced compounds. To date, we have successfully competed for top talent, often in direct competition with much larger pharmaceutical companies with greater resources, in part because of our use of equity-based compensation. We believe that equity awards are central to our employment value proposition and are necessary for us to continue competing for top talent as we grow.

As of December 15, 2018, after the annual addition under the “evergreen provision” on October 1, 2018 and the aggregate annual equity awards for year end 2018 had been determined, there were 469,463 shares available for grant under the 2012 Equity Plan. As part of the proposed 2019 Equity Plan, we are proposing to terminate the “evergreen provision. Accordingly, without the proposed reserve in the 2019 Equity Plan, and assuming we would otherwise terminate the “evergreen provision” of the 2012 Equity Plan (If the 2019 Equity Plan is not approved by stockholders at the 2019 annual meeting, the 2012 Equity Plan will remain in place with its “evergreen provision” still operative.), our ability to provide equity incentives for our planned new hires, as well as our existing employees and management team, would be severely limited. In turn, this would place us at a competitive disadvantage because our ability to attract, motivate and retain key personnel would be compromised during a critical growth period.

Our Equity Program is Designed to Incentivize Performance

As noted above, our broad-based equity program generally provides for stock option awards to all employees, which awards are designed to incentivize performance because no value is created unless our stock price increases from the date the options are granted. We grant stock options to new employees that are subject to 25% vesting on the first anniversary of employment with the balance vesting quarterly over the subsequent three years. In addition, we provide annual awards of stock options to all employees that are subject to quarterly vesting over four years from the date of grant.

In the case of our management team, the Compensation Committee has made awards of stock options, in line with our other employees, as well as performance share units. The performance share units are divided into

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two types with one half, the PSUs, tied to corporate goals and one half, the rTSRUs, tied to stock performance. Specifically, the PSUs are subject to research and development goals based on advancement of our priority programs in NASH/PBC, RSV and HCV; the rTSRUs are based on the relative performance of our common stock against the other component companies in the NASDAQ Biotech Index, or ^NBI, over the same 60-day calendar periods two years apart, with no units vesting unless our stock is in at least the 65^th percentile of component companies at the end of the performance period. The performance share units can expire unvested or vest in an amount up to 200% (150% for unit awards granted since 2017) of the target number of units, depending on the company’s performance.

Our Compensation Committee believes that the program of stock options and performance units provides management and our employees appropriate incentives to build the value of our company.

We Have Managed Our Equity Burn Rate Efficiently

In setting the number of new shares to be reserved for issuance under the 2019 Equity Plan and for which stockholder approval is being sought, the Compensation Committee considered the historical amounts of common stock underlying equity awards granted by the Company in the past three years and our projections for the coming year based on the Company’s current employee headcount. In our fiscal years 2016, 2017 and 2018, the Company made equity awards, including a targeted number of shares performance-based unit awards, representing a total of 564,930, 814,079 and 655,695 shares, respectively. The weighted average numbers of shares of our common stock outstanding in 2016, 2017 and 2018 were 18,928,641, 19,065,963 and 19,254,736 shares, respectively. The Company’s three-year average burn rate is 3.55%, including a burn rate of 3.41% in 2018. The reduction in the burn rate in 2018 occurred despite the fact that during the period from March 2013 to December 15, 2018, we almost tripled our employee headcount (from 39 employees to 115).

In addition, the Compensation Committee considered the total amount of stock options and other awards outstanding under existing grants. We had outstanding a total of 3,310,804 equity awards as of December 15, 2018 (commonly referred to as the “overhang”), consisting of stock options to purchase a total of 3,063,303 shares, restricted stock units for 108,701 shares, and performance unit awards targeting a total 138,800 shares, which in the aggregate represent approximately 17% of our outstanding shares as of that date. Our burn rate and overhang are calculated as percentages of our outstanding shares of common stock and may be higher than some of our peers due to the fact that we have not issued any shares of our common stock in an equity financing since the closing of our IPO in March 2013.

After a review of our historical practices and in the context of our current and expected future growth and based on the recommendation of the Compensation Committee, the Compensation Committee believes that the proposed share reserve under the 2019 Equity Plan, in addition to the shares available under the 2012 Equity Plan, would facilitate the Company’s ability to continue to grant equity incentives for at least the next two years, which is vital to our efforts to attract and retain the highly skilled individuals required to support our continued growth in the extremely competitive labor markets in which we compete.

The closing price of our common stock on the Nasdaq Global Select Market on December 14, 2018 was $73.76 per share, compared to $31.88 on December 15, 2016 and $17.18 at the close of our first day of trading in March 2013. Based solely on the closing price of our common stock on December 14, 2018 of $73.76 per share, the aggregate value of the proposed additional 1,600,000 shares of common stock, which would be newly reserved for issuance under the 2019 Equity Plan, is $118,016,000.

Stockholder Approval Requirements

Approval of the 2019 Equity Plan by our stockholders is required under the listing rules of the Nasdaq Stock Market. Stockholder approval will also ensure favorable federal income tax treatment for any awards of incentive stock options that may be made under Section 422 of the Internal Revenue Code of 1986, as amended (the “Code”).

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General Description of 2019 Equity Plan

The purpose of the 2019 Equity Plan is to attract and retain employees, directors and consultants and to provide an incentive for these individuals to achieve long-range performance goals. If approved, the 2019 Equity Plan will permit us, under the direction of the Compensation Committee, to grant equity awards to our employees, directors and consultants, including incentive and non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units and other stock-based and cash-based awards. Approximately 115 employees and 6 non-employee directors will be eligible to participate in the 2019 Equity Plan.

The following section provides an overview of the proposed 2019 Equity Plan, subject to the approval of our stockholders at the 2019 annual meeting.

Administration and Eligibility

Awards are made by the Compensation Committee, which has been designated by our Board of Directors to administer the 2019 Equity Plan. Subject to certain limitations, the Compensation Committee may delegate to one or more of our executive officers the power to make awards to participants who are not subject to Section 16 of the Securities Exchange Act of 1934 and are not “executive officers” for purposes of the Securities Exchange Act of 1934, as amended.

The Compensation Committee will administer the 2019 Equity Plan and determine the terms and conditions of each equity award to our executive officers and directors, including the number of shares subject to the award, the exercise price and the form of payment of the exercise price for any stock option, the vesting conditions of the award and the terms of any withholding of shares or other provisions to satisfy tax withholding requirements for the award.

Types of Awards

The 2019 Equity Plan provides for the following categories of awards:

Stock Options. The Compensation Committee may grant options to purchase shares of common stock that are either incentive stock options, or ISOs, eligible for the special tax treatment described below, or nonstatutory stock options. No option may have an exercise price that is less than the fair market value of the common stock on the date of grant or a term of more than ten years. An option may be exercised by the payment of the option price in cash or with such other lawful consideration as the Compensation Committee may determine, including by delivery of shares of common stock owned by the optionholder, by a broker-assisted cashless exercise, or by Enanta retaining shares otherwise issuable pursuant to the option.

Restricted Stock. Our Compensation Committee may grant shares of common stock that are only earned if specified conditions, such as a completing a term of employment or satisfying pre-established performance goals, are met and that are otherwise subject to forfeiture. Shares of restricted stock may not be sold, transferred or otherwise encumbered until earned, unless the Compensation Committee provides otherwise.

Restricted Stock Units. Our Compensation Committee may grant units that represent the right to receive shares of our common stock, subject to such terms, restrictions, conditions, performance criteria, vesting requirements, settlement terms, and payment rules, if any, as the Committee shall determine.

Unrestricted Stock. Our Compensation Committee may grant shares of common stock that are not subject to restrictions or forfeiture.

Stock Appreciation Rights. Our Compensation Committee may grant stock appreciation rights, or SARs, where the participant receives cash, shares of common stock, or other property, or a combination thereof, as determined by the Compensation Committee, equal in value to the difference between the exercise price of the SAR and the fair market value of the common stock on the date of exercise. SARs may be granted in tandem with options (at or after award of the option) or alone and unrelated to an option. SARs in tandem with an option shall terminate to the extent that the related option is exercised, and the related option shall terminate to the

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extent that the tandem SARs are exercised. SARs granted in tandem with options shall have an exercise price not less than the exercise price of the related option. SARs granted alone and unrelated to an option shall have an exercise price not less than 100% of the Fair Market Value of the common stock on the date of award may be granted at such exercise prices as the Committee may determine.

Stock Dividends and Stock Splits

If our common stock is subdivided or combined into a greater or smaller number of shares or if we issue any shares of common stock as a stock dividend, the number of shares of our common stock thereafter deliverable upon the exercise of an outstanding option or upon issuance under another type of award shall be appropriately increased or decreased proportionately, and appropriate adjustments shall be made in the per share purchase price and performance goals applicable to performance-based awards, if any, to reflect such subdivision, combination or stock dividend.

Other Dividends

Dividends (other than stock dividends as described above) may accrue but are not payable prior to the time, and only to the extent that, the underlying shares have vested or restrictions or rights to reacquire shares subject to awards have lapsed.

Corporate Transactions

Upon a merger, consolidation or other reorganization event, our Board of Directors, may, in its sole discretion, take any one or more of the following actions pursuant to the 2019 Equity Plan, as to some or all outstanding awards:

Amendment and Termination

The 2019 Equity Plan may be amended by our stockholders. It may also be amended by our Board of Directors, provided that any amendment approved by our Board which requires stockholder approval (1) under the rules of the Nasdaq Stock Market, (2) in order to ensure favorable federal income tax treatment for any incentive stock options under Section 422 of the Code, or (3) for any other reason, is subject to obtaining such stockholder approval. However, no such action may adversely affect any rights any outstanding awards without the holder’s consent. Other than in connection with stock dividends, stock splits and corporate transactions, as

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summarized above, (i) the exercise price of an option may not be reduced, (ii) an option may not be canceled in exchange for a replacement option having a lower exercise price, or for another award or for cash, and (iii) no other action may be taken that is considered a direct or indirect “repricing,” in each case without stockholder approval.

Duration of the 2019 Equity Plan

The 2019 Equity Plan will become effective upon approval of the plan by vote of our stockholders, which is scheduled for February 28, 2019, and will expire by its terms after the expiration of ten years from the anniversary of the date of the original approval by our stockholders unless extended by a subsequent vote of our stockholders approving an increase in the maximum number of shares that may be issued under the plan. In the event of any such subsequent approval, the expiration date of the 2019 Equity Plan shall automatically reset to the date ten years from the date of the latest subsequent approval. No awards may be made after termination of the 2019 Equity Plan, although previously granted awards may continue beyond the termination date in accordance with their terms.

Federal Income Tax Consequences Relating to Stock Options and Restricted Stock

Incentive Stock Options. An optionee does not realize taxable income upon the grant or exercise of an incentive stock option, known as an ISO, under the 2019 Equity Plan. If no disposition of shares issued to an optionee pursuant to the exercise of an ISO is made by the optionee within two years from the date of grant or within one year from the date of exercise, then (a) upon sale of such shares, any amount realized in excess of the option price (the amount paid for the shares) is taxed to the optionee as a long-term capital gain and any loss sustained will be a long-term capital loss and (b) no deduction is allowed to Enanta for Federal income tax purposes. The exercise of ISOs gives rise to an adjustment in computing alternative minimum taxable income that may result in alternative minimum tax liability for the optionee.

If shares of common stock acquired upon the exercise of an ISO are disposed of prior to the expiration of the two-year and one-year holding periods described above, referred to as a disqualifying disposition, then (a) the optionee realizes ordinary income in the year of disposition in an amount equal to the excess (if any) of the fair market value of the shares at exercise (or, if less, the amount realized on a sale of such shares) over the option price thereof and (b) Enanta is entitled to deduct this amount. Any further gain realized is taxed as a capital gain, which will be long-term if the shares were held for more than one year following exercise, and does not result in any deduction to Enanta. A disqualifying disposition in the year of exercise will generally avoid the alternative minimum tax consequences of the exercise of an ISO.

Non-statutory Stock Options. No income is realized by the optionee at the time a non-statutory option is granted. Upon exercise, (a) ordinary income is realized by the optionee in an amount equal to the difference between the option price and the fair market value of the shares on the date of exercise and (b) Enanta receives a tax deduction for the same amount. Upon disposition of the shares, appreciation or depreciation after the date of exercise is treated as a capital gain or loss, which will be short-term or long-term depending upon how long the shares have been held, and will not result in any deduction by Enanta.

Restricted Stock. Awards of restricted stock that are non-transferable and subject to forfeiture are generally not taxable to the recipient until the shares vest. When the shares vest, the recipient realizes compensation income equal to the difference between the amount paid for the shares and their fair market value at the time of the vesting, and we are entitled to a corresponding deduction. The tax is payable for the year in which the vesting occurs, regardless of whether the shares are sold at that time. Upon subsequent disposition of the shares, any appreciation or depreciation is treated as short-term or long-term capital gain or loss, depending on the length of time the recipient has held the shares after the date on which the shares vested.

Instead of being taxed when the shares vest, a recipient may elect to be taxed in the year the shares are awarded by filing a “Section 83(b) election” with the Internal Revenue Service within 30 days after issuance of

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the restricted shares. The recipient then realizes compensation income in the year of the award equal to the difference between the amount paid for the shares and their fair market value at the time of issuance, and Enanta is entitled to a corresponding deduction at that time. Upon subsequent disposition of the shares, any appreciation or depreciation is treated as short-term or long-term capital gain or loss, depending on the length of time the recipient has held the shares since the date of receipt of the shares.

Unrestricted Stock. Generally, a recipient will be taxed at the time of the grant of the award. The fair market value of the shares at that time will be treated as ordinary income and Enanta is entitled to receive a tax deduction for the amount reported as ordinary income. Upon disposition of the shares, any appreciation or depreciation since the time of grant is treated as short-term or long-term capital gain or loss, depending on the length of time the recipient has held the shares.

Restricted Stock Units. A recipient does not realize taxable income upon the grant or vesting of a restricted stock unit. When a stock unit is settled, i.e. when the underlying share of common stock is issued to the recipient, the recipient realizes ordinary income in an amount equal to the fair market value of the shares distributed to settle the award, and Enanta is entitled to a tax deduction for such amount. If the award is settled in shares, then upon disposition of the shares any subsequent appreciation or depreciation is treated as short- or long-term capital gain or loss, depending on the length of time the recipient has held the shares since the date of settlement.

Internal Revenue Code Section 162(m) Limitation on Deductibility of Certain Equity Awards

After enactment of the Tax Cuts and Jobs Act of 2017, United States tax law generally does not allow publicly-held companies to obtain tax deductions for compensation of more than $1.0 million paid in any year to any of the chief executive officer, the chief financial officer and the next three highest paid executive officers, as well as any officer who was treated as a covered employee under Section 162(m) of the U.S. Internal Revenue Code of 1986, as amended, for any year beginning after December 31, 2016 (each, a “covered employee”). As a result, Enanta will not be entitled to a compensation deduction with respect to awards under the 2019 Equity Plan to a covered employee to the extent the aggregate amount payable results in total compensation in excess of the $1.0 million limit.

The preceding summary is qualified in its entirety by reference to the full text of the 2019 Equity Plan, which is attached as Appendix A to this proxy statement.

Equity Compensation Plan Information

The following table provides information about the securities authorized for issuance under the Company’s equity compensation plans as of September 30, 2018:

Equity Compensation Plan Information

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New Plan Benefits Table

The issuance of any awards under the 2019 Equity Plan will be at the discretion of our Compensation Committee. Therefore, it is not possible to determine the amount or form of any award that will be granted to any individual in the future.

Vote Required

The affirmative vote of a majority of the shares represented in person or by proxy at the annual meeting and entitled to vote on this proposal will constitute the approval of our 2019 Equity Plan. Abstentions and broker non-votes will not be treated as votes cast for the purpose of determining the outcome of this proposal.

Recommendation

We recommend a vote “FOR” the proposal to approve the 2019 Equity Plan.

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PROPOSAL 3

ADVISORY VOTE ON APPROVAL OF THE FREQUENCY OF HOLDING AN ADVISORY VOTE ON

THE COMPENSATION OF OUR NAMED EXECUTIVE OFFICERS

We are seeking your input with regard to the frequency of holding future stockholder advisory votes on the compensation of our named executive officers. {Based on the “say-on-frequency” votes of other companies in our industry, we believe an annual “say-on-pay” vote best meets the expectations of our stockholders. Therefore, we are recommending that future “say-on-pay” votes be conducted on an annual basis.

The proxy card provides stockholders with the opportunity to choose among three options for holding the advisory vote in future proxy statements:

The affirmative vote of a majority of the shares voted for this proposal will be the frequency approved, on an advisory basis, by our stockholders. However, because the vote on the frequency of holding future advisory votes on the compensation of our named executive officers is not binding, if none of the frequency options receives a majority vote, the option receiving the greatest number of votes will be considered the frequency preferred by our stockholders.

We understand that our stockholders may have different views as to what is the best approach for Enanta, and we look forward to hearing from our stockholders on this proposal.

Recommendation

We recommend that stockholders vote “FOR” the frequency of an advisory vote on executive compensation being every year.

PROPOSAL 4

ADVISORY VOTE TO APPROVE THE COMPENSATION PAID TO

OUR NAMED EXECUTIVE OFFICERS

We are providing our stockholders with the opportunity to cast an advisory (non-binding) vote on executive compensation, or a “say-on-pay” vote. Under Section 14A of the Securities Exchange Act of 1934, we must hold this advisory vote at least once every three years thereafter.

The say-on-pay vote is a non-binding vote on the compensation paid to our named executive officers, as described elsewhere in this proxy statement under the heading “Executive Compensation,” and includes the “Compensation Discussion and Analysis,” the tabular disclosure regarding such compensation and the accompanying narrative disclosure set forth elsewhere in this proxy statement. The Executive Compensation section describes our compensation philosophy and objectives, how we determine executive compensation, the elements of total compensation and the actual compensation of our named executive officers identified in that section. The Compensation Committee and our Board believe that the policies and practices described in the “Compensation Discussion and Analysis are effective in implementing our compensation philosophy and objectives and that the compensation of our named executive officers for 2018 reflects and supports those policies and practices.

The say-on-pay vote is not binding on the Compensation Committee or our Board. However, the Compensation Committee and the Board will take into account the result of the vote when determining future executive compensation arrangements.

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Recommendation

We recommend a vote “FOR” the proposal to approve, on an advisory basis, the compensation paid to our named executive officers, as described in this proxy statement.

PROPOSAL 5

RATIFICATION OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The firm of PricewaterhouseCoopers LLP, an independent registered public accounting firm, has audited our financial statements for each of the years ended September 30, 2018, 2017 and 2016. Our Audit Committee has appointed them to serve as our auditors for the fiscal year ending September 30, 2019. Detailed disclosure of the audit and tax fees we paid to PricewaterhouseCoopers LLP in 2018 and 2017 may be found in the “Audit Fees” section of this proxy statement. Based on these disclosures and information in the Audit Committee Report provided elsewhere in this proxy statement, our Audit Committee is satisfied that PricewaterhouseCoopers LLP is sufficiently independent of management to perform its duties properly. Although not legally required to do so, our Board considers it desirable to seek, and recommends, stockholder ratification of our selection of PricewaterhouseCoopers LLP as our independent registered public accounting firm for fiscal year 2019. If the stockholders fail to ratify our selection, the Audit Committee will reconsider whether or not to retain that firm. Even if the selection is ratified, the Audit Committee in its discretion may direct the appointment of a different independent registered public accounting firm at any time during the year if the Audit Committee determines that such a change would be in the best interest of Enanta and its stockholders.

Recommendation

We recommend a vote “FOR” ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm.

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CORPORATE GOVERNANCE

Board and Committee Matters

Board Leadership and Independence. Our Board of Directors has determined that Bruce L.A. Carter, Ph.D., as well as those director nominees and those directors continuing their terms after the 2019 Annual Meeting, are independent directors as defined by applicable Nasdaq Stock Market standards governing the independence of directors, except that Jay R. Luly, Ph.D., our President and Chief Executive Officer, is not considered independent. Dr. Carter has served as our non-executive Chairman of the Board since December 2015. Dr. Luly continues to be responsible for setting the strategic direction for our Company and the day-to-day leadership and performance of the Company.

Board Meetings and Committees. Our Board of Directors held 5 meetings during 2018, and the independent directors held executive sessions at 4 of the meetings of the Board. During 2018, each of the directors then in office, attended at least 75% of the aggregate of all meetings of the Board of Directors and all meetings of the committees of the Board of Directors on which such director then served.

Continuing directors and nominees for election as directors in a given year are required to attend the annual meeting of stockholders, barring significant commitments or special circumstances. All of our directors then serving as directors attended our 2018 annual meeting of stockholders, except for Dr. Carter, who had planned to attend but could not due to travel delays.

Stockholder Communications. Any stockholder wishing to communicate with our Board of Directors, a particular director or the chair of any committee of the Board of Directors may do so by sending written correspondence to our principal executive offices, to the attention of the Chairman of the Board. All such communications will be delivered to the Board of Directors or the applicable director or committee chair.

During 2018, our Board of Directors had three standing committees: Audit Committee, Compensation Committee and Nominating and Corporate Governance Committee.

Audit Committee.

Our Audit Committee’s responsibilities include:

The members of our Audit Committee during 2018 were Messrs. Buckley and Vance and Dr. Russell with Mr. Buckley serving as Chair of the committee. All members of our Audit Committee meet the requirements for

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financial literacy under the applicable rules and regulations of the SEC and Nasdaq. Our Board has determined that Mr. Buckley is an Audit Committee financial expert as defined under the applicable rules of the SEC and has the requisite financial sophistication as defined under the applicable rules and regulations of Nasdaq. Our Board has determined that each of and Dr. Russell and Messrs. Buckley and Vance are independent under the applicable rules of Nasdaq and under the applicable rules of the SEC. The Audit Committee held 5 meetings during 2018. The Audit Committee operates under a written charter that satisfies the applicable standards of the SEC and Nasdaq. A copy of the Audit Committee charter is available in the “Investors – Corporate Governance” section of the Company’s website at www.enanta.com.

Compensation Committee.

Our Compensation Committee’s responsibilities include:

The members of our Compensation Committee during 2018 were Drs. Carter and Golumbeski and Mr. Vance and Ms. Peterson. Dr. Golumbeski chairs our Compensation Committee. None of the members of our Compensation Committee has at any time been one of our officers or employees. None of our executive officers currently serves, or in the past fiscal year has served, as a member of the Board or Compensation Committee of any entity that has one or more executive officers on our Board or Compensation Committee. Each of the members of our Compensation Committee is independent under the applicable rules and regulations of Nasdaq and is a “non-employee director” as defined in Rule 16b-3 promulgated under the Exchange Act. The Compensation Committee held 6 meetings during 2018. The Compensation Committee operates under a written charter adopted by the Board, which is available in the “Investors – Corporate Governance” section of our website at www.enanta.com.

For more information regarding the authority of our Compensation Committee, the extent of delegation to our Compensation Committee, our processes and procedures for determining executive compensation and the role of executive officers and compensation consultants in determining or recommending the amount or form of compensation for directors and executive officers, please see “Executive Compensation – Compensation Discussion and Analysis” in this proxy statement.

Nominating and Corporate Governance Committee.

Our Nominating and Corporate Governance Committee’s responsibilities include:

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The current members of our Nominating and Corporate Governance Committee are our independent directors, namely Drs. Carter, Golumbeski and Russell, Messrs. Buckley and Vance and Ms. Peterson. Mr. Vance chairs the Nominating and Corporate Governance Committee. Each of the members of our Nominating and Corporate Governance Committee is an independent director under the applicable rules and regulations of Nasdaq relating to Nominating and Corporate Governance Committee independence. The Committee held two meetings during 2018. The Nominating and Corporate Governance Committee operates pursuant to a written charter, which is available in the “Investors – Corporate Governance” section of our website at www.enanta.com.

The Nominating and Corporate Governance Committee considers candidates for Board membership suggested by its members and the Chief Executive Officer. In 2013 it also established a subcommittee consisting of Messrs. Vance and Buckley (the “Nominating Subcommittee”) to work with an independent recruiting firm and Dr. Luly to help identify and recruit additional candidates, which resulted in the recruitment of Drs. Carter, Golumbeski, Russell and Ms. Peterson. Additionally, in selecting nominees for directors, the Nominating and Corporate Governance Committee will review candidates recommended by stockholders in the same manner and using the same general criteria as candidates recruited by the committee and/or recommended by the Board. Any stockholder who wishes to recommend a candidate for consideration by the committee as a nominee for director should follow the procedures described later in this proxy statement under the heading “Stockholder Matters-Stockholder Recommendations for Director Nominations.” The Nominating Subcommittee will also consider whether to nominate any person proposed by a stockholder in accordance with the provisions of our bylaws relating to stockholder nominations as described later in this proxy statement under the heading “Stockholder Matters-Deadline for Stockholder Proposals and Director Nominations.”

The process used by the Nominating Subcommittee in 2013 is likely to be the process for any future director searches. In 2013, the Nominating Subcommittee started the director search process by identifying a mix of types of experience and personal characteristics that the Nominating Subcommittee considered most valuable to complement the skills and experience of existing directors. Once the Nominating Subcommittee had identified prospective nominees, the Subcommittee then made an initial determination as to whether to conduct a full evaluation of the candidate. This initial determination was based on the information provided to the Subcommittee in a report from the recruiting firm, as well as the Subcommittee’s own knowledge of the prospective candidate. The preliminary determinations were based primarily on the need for additional Board members to fill vacancies or expand the size of the Board and the likelihood that the prospective nominee could satisfy the evaluation factors described below. The Subcommittee then evaluated the prospective nominees against the standards and qualifications set out in our Corporate Governance Guidelines, which include among others:

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Although the Committee does not have a formal policy for considering diversity in identifying nominees for director, it has sought a variety of occupational and personal backgrounds on the Board in order to obtain a range of viewpoints, perspectives and skills.

If the Nominating Subcommittee’s initial evaluation was positive, the members of the Nominating Subcommittee each interviewed the candidate. Upon completion of this evaluation and interview process, the Nominating Subcommittee made a recommendation to the full Board as to whether the candidate should be nominated by the Board and invited other directors to interview the candidate in person or by phone. The Board then determined whether to approve the nominee after considering the recommendation and report of the Nominating Subcommittee.

In November 2018, the Nominating and Corporate Governance Committee established a subcommittee (the “Nominating Committee”) for the purpose of determining the director nominees for election at the 2019 annual meeting of stockholders. The Nominating Committee consists of Mr. Vance, Ms. Peterson and Drs. Carter and Golumbeski, who are all independent directors. In December 2018, the Nominating Committee approved the director nominees for election at the 2019 annual meeting.

Risk Oversight.

The Board’s role in our risk oversight process includes receiving reports from time to time from the Audit Committee on areas of material risk to the Company, including operational, financial, legal and regulatory, and strategic and reputational risks.

Certain Relationships and Related Transactions

Policy on Related Person Transactions

Our Board of Directors has adopted a written Policy on Related Person Transactions that sets forth our policies and procedures for the reporting, review, and approval or ratification of each related person transaction. Our Audit Committee is responsible for implementing this policy and determining that any related person transaction is in our best interests. The policy applies to transactions and other relationships that would need to be disclosed in this proxy statement as related person transactions pursuant to SEC rules. In general, these transactions and relationships are defined as those involving a direct or indirect interest of any of our executive officers, directors, nominees for director and 5% stockholders, as well as specified members of the family or household of any of these individuals or stockholders, where we or any of our affiliates have participated in the transaction (either as a direct party or by arranging the transaction) and the transaction involves more than $120,000. In adopting this policy, our Board expressly excluded from its coverage any transactions, among others, involving compensation of our executive officers or directors that it or our Compensation Committee has expressly approved.

We have not engaged in any transactions with related persons since the beginning of our 2018 fiscal year.

Compensation Committee Interlocks and Insider Participation

During 2018, the Compensation Committee members were Drs. Carter and Golumbeski, Ms. Peterson and Mr. Vance, none of whom currently is, or formerly was, an officer or employee of Enanta. None of our executive officers served as a member of the Board of Directors or Compensation Committee of any other company that had one or more executive officers serving as a member of our Board of Directors or Compensation Committee.

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EXECUTIVE OFFICERS

The following section provides biographical information as of December 1, 2018 about our current executive officers:

Jay R. Luly, Ph.D., has served as our President and Chief Executive Officer and as a member of our board of directors since July 2003. Prior to joining Enanta, Dr. Luly was an Entrepreneur in Residence at Oxford Bioscience Partners. Before joining Oxford in March 2002, Dr. Luly held the positions of Senior Vice President, Research and Development Operations and Senior Vice President, Discovery Strategy and Operations at Millennium Pharmaceuticals following Millennium’s merger with LeukoSite, Inc., where he had served as Senior Vice President, Drug Discovery and Preclinical Development. Prior to joining LeukoSite, he held a number of senior drug discovery positions at Abbott Laboratories from 1983 to 1997. Dr. Luly received a B.S. from the University of Illinois, Urbana/Champaign and a Ph.D. in synthetic organic chemistry from the University of California, Berkeley.

Yat Sun Or, Ph.D., has been our Senior Vice President, Research and Development and Chief Scientific Officer since November 1999. Prior to joining Enanta, Dr. Or held key leadership positions at Abbott Laboratories from 1985 to 1999, where he received two Chairman’s Awards for his outstanding research, which led to the discovery and development of immunosuppressant and antibacterial drugs. Prior to Abbott, Dr. Or was a member of the cardiovascular drug discovery team at Schering-Plough. Dr. Or received his Ph.D. in Organic Chemistry from the University of Chicago and completed Postdoctoral Fellowships at Ohio State University and Indiana University.

Nathalie Adda, M.D., has been our Senior Vice President and Chief Medical Officer since June 2015. Prior to joining Enanta, Dr. Adda was Chief Medical Officer, VP Clinical Development, Medical and Regulatory Affairs at Transgene SA, where she led the Oncology and Infectious Disease programs since 2012. From 2006 to 2012, she was Senior Medical Director and the medical lead for the Incivek^® (telaprevir) Clinical Program at Vertex Pharmaceuticals, Inc. Earlier in her career, Dr. Adda held medical and research positions at Gilead, Triangle Pharmaceuticals and Boehringer Ingelheim, where she worked on programs for infectious diseases such as human immunodeficiency virus, hepatitis B virus and hepatitis C virus. Dr. Adda is a graduate of the University of Paris, where she received a Doctorate in Medicine, as well as a Master’s Degree in Biostatistics, and where she did post- graduate work in infectious diseases.

Paul J. Mellett has served as our Senior Vice President, Finance & Administration and Chief Financial Officer since September 2003. From April 2001 through August 2003, he held the position of Senior Vice President and Chief Financial Officer of Essential Therapeutics, Inc., a publicly-held biotechnology company. Previously, Mr. Mellett was the Chief Financial Officer and Vice President of Administration at GelTex Pharmaceuticals, Inc., a publicly held biotechnology company that was acquired by Genzyme Corporation in December 2000. From 1994 to 1997, Mr. Mellett served as Chief Financial Officer of Marshall Contractors, a construction management firm specializing in the pharmaceutical, biotechnology and semiconductor industries, which was acquired by Fluor Corporation in 1996. From 1977 to 1994, Mr. Mellett was employed with Deloitte & Touche LLP, a public accounting firm, and was promoted to Audit Partner in 1989. Mr. Mellett received a B.S. in Business Administration from Boston College in 1977.

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Nathaniel S. Gardiner, J.D., has served as our Senior Vice President and General Counsel since May 2014 and has served as our Secretary since 1995. Previously Mr. Gardiner was a corporate and securities law partner for 25 years, most recently at Edwards Wildman Palmer LLP since October 2011, previously at Edwards Angell Palmer & Dodge LLP since November 2005, and before that at Palmer & Dodge LLP, where he represented Enanta and several other biotechnology companies. Mr. Gardiner received his A.B. from Harvard College and his J.D. from the University of Virginia School of Law.

Timothy D. Ocain, Ph.D. has served as our Senior Vice President, New Product Strategy and Development since January 2014. Previously Dr. Ocain had been a consultant to us since March 2012, while he was an independent biotechnology consultant providing consulting services to a variety of companies. From 2006 to 2009, Dr. Ocain was a member of the executive team and Senior Vice President, Research and Development at Seaside Therapeutics, a company focused on neurodevelopmental disorders. Previously, he worked at Millennium Pharmaceuticals from 1998 to 2006 and held positions of increasing responsibility in drug discovery, program management and mostly recently held the position of Vice President, Inflammation Discovery. Before that he worked in drug discovery at Procept, Inc. and at Wyeth-Ayerst Research. Dr. Ocain received his B.S. in Biological Sciences from the University of Wisconsin-Eau Claire and his Ph.D. in Pharmaceutical Chemistry from the University of Wisconsin-Madison, and completed his post-Doctoral Fellowship in Chemistry at the University of Minnesota.

EXECUTIVE COMPENSATION

Compensation Discussion and Analysis

This section provides an overview and analysis of our executive compensation program, including its design and objectives, as well as the rationale applied and the decisions made under our program with respect to the compensation paid or awarded in fiscal 2018 to Drs. Luly, Or and Adda and Messrs. Mellett and Gardiner, whom we refer to collectively as our Named Executive Officers, or NEOs. Later in this proxy statement, you will find a series of tables containing specific information about the compensation earned by these individuals in fiscal 2018. The discussion below is intended to help you understand the detailed information provided in those tables and to put that information into context based on our overall compensation program for our Named Executive Officers.

Our Executive Compensation Philosophy

We rely on the expertise of our executive management team to drive overall company performance. Our compensation program is intended to align the interests of our Named Executive Officers with those of our stockholders by measuring and rewarding their performance against our research and development objectives. Consistent with this pay-for-performance philosophy, the Compensation Committee has structured certain elements of the compensation program for our executive officers, including our NEOs, to reward performance by emphasizing equity compensation opportunities, as well as variable cash incentives that are based on corporate performance measured against annual objectives that are pre-established by the Compensation Committee.

The Compensation Committee has determined that our executive compensation program will generally target the executive team’s base salaries, total target cash compensation and time-based equity awards to those of executives in the 50^th percentile of comparable executives in our peer group companies over time. In addition, the Compensation Committee has expanded our executive team’s total equity compensation opportunity by including performance awards that target reaching approximately the equity compensation of the 75^th percentile of comparable executives in our peer group companies if Enanta achieves high levels of performance against its longer-term objectives and the value of Enanta’s stock increases more relative to the traded stocks of other public biotechnology companies.

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Our compensation philosophy is designed to promote our corporate objectives. Our guiding principles focus on:

Compensation Committee

Our board of directors has delegated authority to the Compensation Committee, which consists of four of our six non-employee directors, to provide oversight of our executive compensation program for our NEOs as well as our other executive officers. The Compensation Committee reviews and evaluates the executive compensation program on an annual basis to ensure that the program is aligned with our compensation philosophy. Since our compensation program is administered on a calendar year basis, the Compensation Committee at its regularly scheduled November meeting reviews our corporate performance for the year and takes the following actions:

The Compensation Committee reviews these actions with the other non-employee directors for their input before finalizing them. In addition, the Compensation Committee makes recommendations to our Board of Directors, based on recommendations made by our compensation consultant, regarding non-employee director fees and equity awards.

Role of Compensation Consultant

Our Compensation Committee retains each year an independent compensation consulting firm to provide advisory services concerning our compensation programs for our executive officers and fees and equity awards for non-employee directors. These services include recommendations regarding our compensation practices and, based on direction from the Compensation Committee, detailed analyses and recommendations based on the percentile rankings of comparable executives, as well as non-employee directors, in our peer group companies. Radford, an AON Consulting company, assisted the Compensation Committee by providing the following services in fiscal 2018:

In addition, the members of the Radford team provide advice to the Compensation Committee and, other than providing data as mentioned below, the Radford team does not provide any other services. Management

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works with Radford at the direction of the Committee to provide the consultant with all information it deems necessary to advise the Committee. Radford follows internal guidelines and practices to guard against any conflict of interest and to ensure the objectivity of its advice and has confirmed the same in writing to us. After review and consultation with Radford, the Compensation Committee has determined that Radford is independent of the company and the members of the committee.

Role of Company Management

Our CEO makes recommendations to the Compensation Committee concerning our company performance relative to corporate performance objectives and proposed compensation of the other NEOs and other executive officers. In addition, our CEO leads management in setting the research and development objectives that are used as the performance objectives for the variable cash compensation plan, subject to Compensation Committee review and approval, and he reviews any adjustments to our proposed peer group and provides suggestions to Radford for inclusions or exclusions. Our CEO works closely with the Compensation Committee to ensure that the Compensation Committee is provided with the appropriate information to make its decisions, including with respect to the performance of each executive officer relative to their individual annual performance objectives, and to propose recommendations for Compensation Committee consideration regarding the compensation elements of the other NEOs. Once our CEO has made his recommendations to the Compensation Committee, this committee reviews them, including consultation with the other non-employee directors regarding our CEO’s compensation, and makes the final compensation determinations. Once the Compensation Committee evaluates compensation data from Radford and makes its final determinations for the other NEOs and other executive officers, those determinations are delivered to our CEO, who then communicates them to the management team.

Benchmarking and Use of Peer Group Data

Our executive compensation program seeks to provide total compensation at pay levels of executives with similar roles at comparable companies when targeted levels of performance are achieved. Use of survey data from our peers plays a significant role in the structure of the compensation program as it is a primary input in setting target levels for base salaries, variable cash compensation and equity awards. These data also help to ensure that we provide compensation that is competitive with the market so that we can attract, retain and motivate talent.

As indicated above, the Compensation Committee retains Radford to conduct a study of peer companies for the purpose of reviewing the compensation levels of our executive team, including the NEOs. Radford provides proposed changes, if any, to our peer group to the Compensation Committee and the Compensation Committee reviews the peer group and, based on the available data and input from members of the Committee, determines and approves the final peer group. The Compensation Committee uses the peer group data to help identify a reasonable benchmark for base salaries, target variable cash compensation, time-based equity awards and target performance-based equity awards and then analyzes company and individual performance to determine whether it is appropriate to move away from this baseline. Peer group data also plays a role in determining the non-cash compensation that is paid to the NEOs, as the market data we obtain regarding companies in our peer group informs what types and amounts of non-cash compensation are appropriate for competitive purposes. We believe that the design of our executive compensation program, with its emphasis on reward for achievement of the key objectives that comprise our annual and long-term business plan, does not create incentives for our executives to take excessive or unnecessary risks that could threaten the value of our company.

We also participate in compensation surveys conducted by Radford each year. The company has access to the resulting Radford reports, which are specific to the pharmaceutical and biotech industry and provide data on salaries, bonuses and equity grants for specific job functions. We use this information when reviewing the salaries and other compensation for all of our employees.

The Compensation Committee retained Radford to conduct a competitive benchmarking analysis on executive compensation for compensation decisions to be made at its November 2017 meeting. As an initial step

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in that process, Radford reviewed the prior year’s criteria and, based on increases in our headcount and market capitalization, recommended changes to establish a peer group of companies that met some or all of the following criteria:

Radford reviewed the peer group approved by the Compensation Committee in calendar 2016 and determined that a number of these companies did not meet the calendar 2017 criteria. As a result, Merrimack Pharmaceuticals, NewLink Genetics, OncoMed Pharmaceuticals and Opthotech were removed from the peer group, primarily due to the substantial increase in our market capitalization criteria, and Halozyme Therapeutics and Momenta Pharmaceuticals were added to our peer group.

Based on the criteria set forth above, the final group of peer companies approved by the Compensation Committee in calendar 2017 was composed of the following companies:

The Compensation Committee, with the assistance of Radford, made several changes to the peer group in September 2018 for purposes of year-end calendar 2018 compensation analysis and determinations. At that time, the criteria were adjusted to increase the range of market values to be generally between $600 million and $5.4 billion, the range of annual revenues to $75 million to $675 million, and the range of employees to 50 to 450, and to add a criterium of research and development expense in the range of $40 million to $250 million. Based on the revised criteria, the Compensation Committee removed from the peer group Achillion Pharmaceuticals, Celldex Therapeutics, Curis, Cytokinetics and Rigel Pharmaceuticals, primarily due to changes in the updated market capitalization criteria for our peer group, as well as Sucampo, which was acquired, and added Acorda Therapeutics, Arena Pharmaceuticals, FribroGen, Intercept Pharmaceuticals, MacroGenics, Mirati Therapeutics and Sangamo Therapeutics.

Executive Compensation Elements

The main components of our executive compensation program are:

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The following discussion describes how each of these elements of compensation fit into our overall compensation objectives and describes how and why compensation decisions were made with respect to each element based on our compensation consultant’s analysis of competitive market data and our annual review of corporate and individual performance.

Base Salaries

Base salaries are paid in order to provide a fixed component of compensation for our NEOs and other executive officers to reward the individual value that each NEO brings to us through experience and past and expected future contributions to our success. At the Compensation Committee meeting on November 16, 2017, the Committee established the base salaries of the NEOs for calendar year 2018 to be within a range that is competitive with salaries paid to executives in the 50^th percentile among comparable executives at companies in our peer group. The Compensation Committee increased the base salary of each of our NEOs for calendar year 2018 from 2017 levels primarily based on the applicable peer group data for comparable executives.

Annual Variable Cash Compensation

Our variable cash compensation program is intended to reward corporate performance and individual performance, by providing our executive officers with an opportunity to receive additional cash compensation, which is based on both the company’s performance relative to the corporate objectives and, the Compensation Committee’s assessment of how well the executive officer performed against his or her individual objectives during the applicable year. The CEO’s variable cash compensation is determined solely based on the company’s performance relative to corporate objectives.

Target Setting. Variable cash compensation targets, which are set as a percentage of base salary for all NEOs and other executive officers, were set within a range that is competitive with annual variable cash compensation paid to executives in the 50^th percentile among comparable executives at companies in our peer group. The Compensation Committee has the discretion to adjust each NEO’s target as it deems appropriate. Potential reasons for adjusting cash bonus targets include considerations of pay equity within Enanta and how the officer’s base salary, upon which the bonus is based, has increased historically.

Elements of Variable Cash Compensation. For all executive officers other than the CEO, target variable cash compensation is determined based on two components: corporate performance and individual performance. The target percentages and the relative weighting of objectives for the NEOs for the variable cash compensation paid at the end of calendar 2017 were as follows:

For variable cash compensation in calendar 2018, the Compensation Committee adjusted the weighting of the elements for NEOs other than our CEO so that corporate performance would be 70% of variable cash compensation and individual performance would be 30%.

Corporate Performance Objectives. Near the beginning of each calendar year, the Compensation Committee, after considering the recommendations of management and our overall strategic goals, confirms our corporate objectives for the year and the proportional emphasis placed on each broad category of objectives. These objectives generally relate to categories that can add the most value to Enanta, such as research and

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development objectives, which constitute a substantial majority of the weighting of the objectives, and other factors primarily within management’s control. Because they are outside of management’s control, the level of sales achieved for our products licensed to AbbVie is not a factor considered in determining annual variable compensation. Our Compensation Committee determines the level of achievement of the corporate objectives for each year. This achievement level is then applied to the portion of each NEO’s target bonus determined by corporate performance for that year.

Our annual corporate performance is measured against our achievement of the key research and development objectives for the year. Accordingly, at the beginning of calendar 2017, our CEO proposed objectives primarily focused on the advancement of our research and development pipeline in RSV, NASH/PBC and HBV. The Compensation Committee then reviewed and revised these objectives and their weighting. In November 2017 the Compensation Committee reviewed our performance against these objectives related to the following:

The Compensation Committee, which has full discretion to determine corporate performance against our annual corporate objectives, determined that we had achieved, or would achieve, substantially all the calendar 2017 performance objectives, and awarded a corporate performance rating of 100%. After reviewing our CEO’s recommendations with respect to the individual performance of the NEOs other than our CEO, the Compensation Committee also determined that our Chief Scientific Officer and our Chief Medical Officer achieved 108% and 105% of their respective individual objectives, several of which were specific research and clinical objectives closely tied to the company’s ability to achieve the corporate objectives described above, and that our Chief Financial Officer and our General Counsel each achieved 100% of their individual objectives related to the performance of their respective groups and their individual responsibilities.

The “Summary Compensation Table” following this discussion includes information, under the column “Non-Equity Incentive Plan Compensation”, concerning the actual variable cash compensation paid to each NEO during the fiscal year ended September 30, 2018.

Long-term Equity Incentive Awards

Equity awards have the potential to be a significant component of each NEO’s compensation package. We emphasize equity awards to motivate our NEOs to drive the long-term performance of Enanta and to align their interests with those of our stockholders. We believe this emphasis is appropriate as these officers have the greatest role in establishing Enanta’s direction and should have a significant proportion of their compensation aligned with the long-term interests of stockholders. The Compensation Committee has established two types of equity awards to serve as these long-term incentives.

Stock Options with Time-Based Vesting. The Compensation Committee makes annual grants of stock options to provide a certain amount of equity to officers that will vest as long as the officer continues to work at Enanta. These grants align the interests of our NEOs with those of our stockholders because the grants will only have value as long as the market value of our common stock increases from the date of grant. To encourage

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retention and focus our executives on building long-term value for our stockholders, we typically structure our annual stock option awards so that they vest over a service period of four years. The size of stock option awards for our NEOs is then set within a range that is competitive with equity awards granted to comparable officers at companies in our peer group. The number of shares subject to each NEO stock option is based primarily on Radford’s determination of the Black-Scholes value of equity awards granted to executives in the 50^th percentile of executives in comparable roles in our peer group companies, and then using that value to determine a number of shares of our common stock based on our Black-Scholes formula used to value our stock options in our financial statements. The Compensation Committee makes final adjustments to the specific number of shares after receiving recommendations from our CEO.

On November 17, 2017, the Compensation Committee granted to each of our NEOs awards of non-statutory stock options vesting over four years in equal quarterly installments with respect to a designated number of shares as follows: Dr. Luly, 100,000 shares; each of Drs. Or and Adda, 23,500 shares; Mr. Mellett, 22,500 shares; and Mr. Gardiner, 21,500 shares.

Restricted Stock Units with Performance-Based Vesting. To provide additional incentive for longer-term performance that can allow our executive officers to achieve levels of equity awards at or above the 75^th percentile of executives in comparable roles in our peer group companies, the Compensation Committee also makes annual awards of performance share units, or PSUs, and relative total stockholder return units, or rTSRUs, to each of our executive officers. Half of these units are designed to vest based on high levels of performance against specific research and development and non-financial business objectives over a two-year period. The other half are designed to vest based on high relative total stockholder returns of our common stock versus the stocks of the other companies in the NASDAQ Biotech Index over a 26-month period.

To initially bracket the target number of units, Radford determines the difference in the dollar values of the annual equity awards for executives in the 50^th percentile and the 75^th percentile of comparable executives in our peer group companies, and then converts that differential value into a number of full value shares of our common stock based on our Black-Scholes formula used to value our stock options in our financial statements. Based on that number of shares, the Compensation Committee then determines a target number of total units for each NEO, based in part on considerations of pay equity and the relative roles of the NEOs. The resulting target number of units is then split evenly between PSUs and rTSRUs for each NEO. These unit awards typically have a performance period of two years, ending on December 31 of the second year, and then after the Compensation Committee determines the level of performance achieved, and provided that the NEO is still employed at Enanta, the underlying shares settle and are issued in the following February.

In the case of the PSUs awarded in fiscal 2018, unit vesting will be based on achievement of research and development milestones in each of three categories of activities: (i) advancement of clinical programs; (ii) advancement of research programs; and (iii) other value-driving opportunities generally involving assets outside of our research and development programs. These milestones, which relate to our key programs, are weighted based on the Compensation Committee’s assessment of the relative value of the milestones. Each program’s milestone is considered to be challenging, meaning that the likelihood of success during the performance period is possible, but not high, because every development activity for the particular program will have to progress substantially as and when planned in order to achieve the two-year objective for that program. General experience in research and development in biotechnology has demonstrated that over a period of two years these types of early stage programs rarely progress exactly as planned, primarily because delays due to matters outside of Enanta are common. In addition to project delays, the failure rate is quite high for compounds in the early stages of discovery and preclinical and early clinical development.

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On March 1, 2018, the Compensation Committee awarded our executive officers PSUs with milestones in each of the three categories:

Achievement of one of the clinical milestones will vest 70% of each NEO’s target number of PSU shares and achievement of a second clinical milestone will vest an additional 50% (reflecting a vesting of 120% of the target number of PSU shares), achievement of one research or other value driving milestone will vest 15% of the target number of PSUs, but achievement of additional milestones in those categories will not vest any additional shares. If one milestone in each of the three categories is achieved by December 31, 2019, then each NEO’s target number of PSU shares will vest, and if an additional clinical milestone is achieved, then 150% of each NEO’s target number of PSU shares will vest. The maximum payout for PSUs awarded in fiscal 2018 is capped at 150% of each NEO’s target number of PSU shares.

In the case of the rTSRUs awarded on March 1, 2018, these awards will vest and result in the issuance of shares of our common stock based upon the relative ranking of the total stockholder return, or TSR, of Enanta’s common stock in relation to the TSR of the component companies in the NASDAQ Biotech Index using a comparison of average closing stock prices over the 60-day period ended December 31, 2017 compared to the 60-day period ending December 31, 2019. The rTSRUs are intended to reward increases in the relative market value of our common stock that might not relate directly to specific long-term objectives of internal research and development efforts reflected in the PSUs but that nonetheless are reflected in our market value and our returns for our stockholders. The number of market-based rTSRUs awarded represents the target number of shares of common stock that may be earned; provided, however, that the actual number of shares that may be earned ranges from 0% to 150% (0% to 200% for rTSRUs awarded before 2018) of the target number, depending on Enanta’s ranking in that index. No rTSRU shares will vest if there is no increase in the value of Enanta’s stock during the period, nor will any rTSRU shares vest if Enanta’s stock is ranked below the 65^th percentile. The rTSRUs will vest as to 50%, 100% or 150% of the target number of rTSRU shares if the stock is ranked at the 65^th, the 75^th or at or above the 85^th percentiles, respectively. If our ranking falls between the 65^th and 85^th percentiles, there will be interpolation between the fixed vesting amounts of the 65^th, 75^th and 85^th percentiles based on the relative ranking of our stock.

Benefits

Health and Welfare Benefits. Our NEOs are eligible to participate in all of our employee benefit plans, including our medical, dental, vision, group life and disability insurance plans, in each case on the same basis as other employees. We believe that these health and welfare benefits help ensure that we have a productive and focused workforce through reliable and competitive health and other benefits.

Retirement Savings. All of our full-time employees, including our NEOs, are eligible to participate in our 401(k) plan. Pursuant to our 401(k) plan, employees may elect to reduce their current compensation by up to the statutorily prescribed annual limit (which was $18,500 in calendar 2018), with additional salary deferrals not to exceed $6,000 available to those employees 50 years of age or older, and to have the amount of this reduction

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contributed to our 401(k) plan. In addition, in 2018 and 2017 we made matching contributions in the amount of 6% of base salary, up to a maximum of $16,200 and $15,900, respectively, per year. In 2016, we made matching contributions in the amount of 5% of base salary, up to a maximum of $13,250 per year. This was based on our policy of making profit-sharing contribution to each employee’s account in amounts ranging from 3% to 6% of base salary and bonus compensation paid in the calendar year, regardless of whether the employee makes a contribution to the 401(k) plan in that year. The percentage of the profit sharing contribution above 3% is based on Enanta’s performance for the year. The 401(k) Plan currently does not offer the ability to invest in our securities.

Perquisites. We do not provide significant perquisites or personal benefits to our NEOs. We do, however, pay the premiums for term life insurance for NEOs.

Severance and Change of Control Benefits

Pursuant to employment agreements, our NEOs are entitled to specified benefits in the event of the termination of their employment under specified circumstances, including termination without cause or for good reason.

We believe that severance protections, particularly in the context of a change of control transaction, can play a valuable role in attracting and retaining executive officers, are an important part of an executive’s total compensation package and are consistent with competitive practices. We believe that the occurrence, or potential occurrence, of a change of control will create uncertainty regarding the continued employment of our NEOs. This uncertainty results from the fact that many change of control transactions result in significant organizational changes, particularly at the senior executive level. Our practice, in the case of our employment agreements, has been to structure these change of control benefits as “double trigger” benefits. In other words, the change of control does not itself trigger benefits; rather, benefits are paid only if the employment of the NEO is terminated during the 12-month (or 18-months in the case of the CEO) period after the change of control. We believe a “double trigger” benefit maximizes stockholder value because it prevents an unintended windfall to executives in the event of a friendly change of control, while still providing them appropriate protections as incentives to cooperate in negotiating any change of control in which their jobs may be at risk. Because we believe that a termination by the executive for good reason is conceptually the same as a termination by us without cause, and that in the context of a change of control potential acquirers would otherwise have an incentive to constructively terminate the executive’s employment to avoid paying severance, we provide severance benefits in these circumstances. We have provided more detailed information about these benefits, along with estimates of their value under various circumstances, under the caption “— Potential Payments Upon Termination, Including Termination After a Change in Control Transaction” below.

Corporate Policies Covering Executive Compensation

Equity Incentive Awards - Mechanics and Timing

The Compensation Committee approves all equity awards to NEOs, including the CEO.

For annual option awards, the grant date is the date during November when the Compensation Committee and the full Board of Directors meet. The Compensation Committee’s procedure for timing of stock option awards assures that grant timing is not being manipulated for employee gain. This grant date timing coincides with Enanta’s calendar-year-based employee review cycle, allowing managers to deliver the equity awards close in time to performance appraisals, which increases the impact of the awards by strengthening the link between pay and performance.

The exercise price for all awards to the NEOs (including the CEO) is the fair market value of our common stock on the date of the grant, which we schedule to be the same date that all our employees receive their annual equity awards. The fair market value of our common stock as of the particular date is defined by the Compensation Committee as the closing price of our common stock on the date of the grant.

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The Compensation Committee does not grant equity awards in anticipation of the release of material nonpublic information. Similarly, we do not time the release of material nonpublic information about the company based on equity award grant dates.

Policy Against Hedging

As part of our insider trading policy, all employees, including executive officers, and members of our board of directors are prohibited from engaging in certain types of hedging transactions involving our securities, specifically short sales, including short sales “against the box,” and purchases or sales of puts, calls or other derivative securities. Our insider trading policy also prohibits certain types of pledges of our securities by all employees, including executive officers, and members of our board of directors, specifically purchases of our securities on margin, borrowing against our securities held in a margin account or pledging our securities as collateral for a loan, with an exception for pledges of our securities as collateral for a loan only after certain prerequisites are met and only with the pre-approval of our Chief Financial Officer.

Policy Against Repricing Stock Options

We have a consistent policy against the repricing of stock options without stockholder approval. In addition, if approved by our stockholders at this meeting, our 2019 Equity Plan will prohibit any action that is considered a direct or indirect “repricing” of stock options unless we obtain stockholder approval.

Federal Tax Considerations under Section 162(m)

Section 162(m) of the Internal Revenue Code of 1986, as amended, or the Code, generally disallows a tax deduction to public companies for compensation in excess of $1 million paid to each of a company’s chief executive officer and the three most highly compensated executive officers (other than the chief executive officer and chief financial officer). Pursuant to the Tax Cuts and Jobs Act of 2017, or the Tax Act, for taxable years beginning after December 31, 2017, the Section 162(m) deduction limitation is expanded so that it also applies to compensation in excess of $1 million paid to a public company’s chief financial officer. Historically, compensation that qualified under Section 162(m) as performance-based compensation was exempt from the deduction limitation. However, subject to certain transition rules, the Tax Act eliminated the qualified performance-based compensation exception. As a result, for taxable years beginning after December 31, 2017, all compensation in excess of $1 million paid to each of the executives described above (other than certain grandfathered compensation in effect before November 2017) will not be deductible by us.

While the Compensation Committee considers the deductibility of awards as one factor in determining executive compensation, the Compensation Committee may also look at other factors in making its decisions and retains the flexibility to award compensation that it determines to be consistent with the goals of our executive compensation program even if the compensation is not deductible by us for tax purposes.

COMPENSATION COMMITTEE REPORT

The Compensation Committee has reviewed the Compensation Discussion and Analysis and discussed that analysis with management. Based on its review and its discussions with management, the Compensation Committee recommended to our Board of Directors that the Compensation Discussion and Analysis be included in this proxy statement.

By the Compensation Committee,

George S. Golumbeski, Ph.D., Chair

Bruce L.A. Carter, Ph.D.

Kristine Peterson

Terry C. Vance

January 17, 2019

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Summary Compensation Table

The following table sets forth information regarding compensation paid to our NEOs:

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The values of the maximum payouts possible for the 2018, 2017 and 2016 rTSRU awards based on the fair value of the rTSRUs at the respective dates of grant and the maximum number of shares issuable under the unit awards based on performance of our common stock are as follows:

The “Stock Awards” column does not include the grant date fair value of the performance share units, or PSUs, awarded during each fiscal year presented because it was not probable at the respective date of grant that the awards would ultimately vest.

The values of the maximum payouts possible for the 2018, 2017 and 2016 PSU awards based on the fair market value of our common stock at the respective dates of grant and the maximum number of shares issuable under the unit awards based on performance against internal research and development objectives are as follows:

The “Stock Awards” column for fiscal 2018 reflects the grant date fair value of the rTSRUs granted in March 2018 to our NEOs.

The “Stock Awards” column for fiscal 2017 reflects the grant date fair value of the rTSRUs granted in January 2017, as well as the grant date fair value of the time-based RSUs granted in November 2016 that vest 50% in December 2019 and 50% in December 2020, subject to the NEO’s continued employment with Enanta.

The “Stock Awards” for fiscal 2016 reflect the grant date fair value of the rTSRUs granted in December 2015. Also included in fiscal 2016 is the grant date fair value of Dr. Adda’s additional 2016 rTSRU award that was a one-time grant for her pro-rated service during the two-year performance period of the rTSRU awards granted to the other executive officers for the period 2015-2016.

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During the 2016 fiscal year, Dr. Adda received pro-rated variable cash compensation based on corporate performance during calendar year 2015 as her employment began with the Company in June 2015.

2018 Grants of Plan-Based Awards

The following table sets forth certain additional information regarding grants of plan-based awards to our NEOs for our 2018 fiscal year under our 2012 Equity Incentive Plan:

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Performance Unit Awards (“PSUs”)

The fair value of the PSUs granted in fiscal 2018 was not included in the table above because on the date of grant, none of the underlying performance milestones were achieved. The PSUs granted in fiscal 2018 will vest as to percentages of the target number of unit shares only upon achievement of specified milestones within three research and development categories by the end of calendar 2019, with the actual number of unit shares that may be earned ranging from 0% to 150% of the target number. Additional details regarding the specified milestones are set forth earlier in this proxy statement under “EXECUTIVE COMPENSATION – Compensation Discussion and Analysis – Long-Term Equity Incentive Awards - Restricted Stock Units with Performance-Based Vesting.”

The values of the target and maximum payouts possible for the 2018 PSU awards based on the fair value at the date of grant and the target and maximum number of units issuable are as follows:

If none of the specified goals within the three research and development categories (“threshold”) are achieved by the end of calendar 2019, none of the unit shares will vest.

Relative Total Stockholder Return Units (“rTSRUs”)

The rTSRUs granted in fiscal 2018 will vest as to percentages of the target number of unit shares based on the relative ranking of the total stockholder return of our common stock in relation to the total stockholder return of the component companies in the NASDAQ Biotech Index over a two year period based on a comparison of average closing stock prices in the last 60 trading days of calendar 2017 and calendar 2019. The actual number of shares that may be earned under the market-based unit ranges from 0% to 150% of the target number.

The values of the target and maximum payouts possible for the 2018 rTSRU awards based on the fair value at the date of grant and the target and maximum number of units issuable, based on performance of our common stock are as follows:

If the minimum total return (“threshold”), as approved by the Compensation Committee, is not achieved by the end of calendar 2019, none of the unit shares will vest.

Stock Options

Each of the option awards has a ten-year term which vest quarterly over four years. The aggregate grant date fair value of stock options granted during the fiscal year is computed in accordance with the provisions of ASC 718. The exercise price of the options is equal to the closing price of our common stock on the date of grant.

2018 Options Exercised and Stock Awards Vested

The following table sets forth the value realized by our NEOs from options to purchase common stock exercised by the NEOs during fiscal 2018 and shares of stock that vested during fiscal 2018. The value realized

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per share for options is based on the difference between the exercise price and the fair market value of our common stock on the date the options were exercised. The value realized upon vesting of the stock awards is based on the fair market value of the shares on the settlement date.

Outstanding Equity Awards at Fiscal 2018 Year-End

The following table summarizes the outstanding equity award holdings of our NEOs as of September 30, 2018:

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