GHDX Genomic Health Inc

SUMMARY

        This summary highlights selected information contained in this proxy statement/prospectus and does not contain all the information that may be important to you. Exact Sciences and Genomic Health urge you to read carefully this proxy statement/prospectus in its entirety, including the annexes. Additional, important information, which Exact Sciences and Genomic Health also urge you to read, is contained in the documents incorporated by reference into this proxy statement/prospectus. See "Where You Can Find More Information" beginning on page 160. All references in this proxy statement/prospectus to Exact Sciences refer to Exact Sciences Corporation, a Delaware corporation, and/or its consolidated subsidiaries, unless the context requires otherwise, all references to Genomic Health refer to Genomic Health, Inc., a Delaware corporation, and/or its consolidated subsidiaries, unless the context requires otherwise, and all references to the merger agreement are to the Agreement and Plan of Merger, dated as of July 28, 2019, by and among Exact Sciences Corporation, Spring Acquisition Corp. and Genomic Health, Inc., as it may be amended, a copy of which is attached as Annex A to this proxy statement/prospectus.

The Parties

Exact Sciences

        Exact Sciences is a molecular diagnostics company focused on the early detection and prevention of some of the deadliest forms of cancer. Exact Sciences has developed an accurate, non-invasive, patient-friendly screening test called Cologuard® for the early detection of colorectal cancer and pre-cancer, and it is currently working on the development of additional tests for other types of cancer, with the goal of becoming a leader in cancer screening and diagnostics.

        Exact Sciences' Cologuard test is a non-invasive stool-based DNA screening test that utilizes a multi-target approach to detect DNA and hemoglobin biomarkers associated with colorectal cancer and pre-cancer. Cologuard targets biomarkers that have been shown to be strongly associated with colorectal cancer and pre-cancer. Methylation, mutation, and hemoglobin results are combined in the laboratory analysis through a proprietary algorithm to provide a single positive or negative reportable result. In September 2019, the U.S. Food and Drug Administration expanded Cologuard's indication to include average-risk individuals ages 45-49. Cologuard is now indicated for average risk adults 45 years of age and older.

        Exact Sciences' commercialization strategy includes three main elements focusing on physicians, patients, and payers. Exact Sciences' sales team actively engages with physicians and their staffs to emphasize the need for colorectal cancer screening, educate them on the value of Cologuard and facilitate their ability to order the test. Exact Sciences focuses on specific physicians based on a combination of Cologuard order history and ordering potential, while also focusing on physician groups and larger regional and national health systems. Exact Sciences also focuses on receiving adequate reimbursement from government insurance plans, managed care organizations and private insurance plans. In addition to Medicare reimbursement, Exact Sciences seeks to secure favorable coverage and in-network reimbursement agreements from commercial payers.

        Exact Sciences' principal executive offices are located at 441 Charmany Drive, Madison, Wisconsin 53719 and its telephone number is (608) 535-8815. Exact Sciences' website address is www.exactsciences.com. Information contained on Exact Sciences' website does not constitute part of this proxy statement/prospectus. Exact Sciences common stock is publicly traded on The Nasdaq Stock Market LLC under the ticker symbol "EXAS." Additional information about Exact Sciences is included in documents incorporated by reference in this proxy statement/prospectus. Please see the section entitled "Where You Can Find More Information" beginning on page 160.

Genomic Health

        Genomic Health is a global provider of genomic-based diagnostic tests that address both the overtreatment and optimal treatment of early and late stage cancer, two of the greatest issues in healthcare today. With Genomic Health's Oncotype IQ Genomic Intelligence Platform, Genomic Health is applying its world-class scientific and commercial expertise and infrastructure to lead the translation of clinical and genomic data into clinically actionable results for treatment planning throughout the cancer patient's journey, from diagnosis to treatment selection and monitoring. Genomic Health's Oncotype IQ Genomic Intelligence Platform is currently comprised of Genomic Health's flagship line of Oncotype DX gene expression tests for breast, prostate and colon cancers, as well as Genomic Health's expanded platform of a liquid-based test, Oncotype DX AR-V7 Nucleus Detect test for advanced stage prostate cancer.

        Genomic Health's principal executive offices are located at 301 Penobscot Drive, Redwood City, California 94063 and its telephone number is (650) 556-9300. Genomic Health's website address is www.genomichealth.com. Information contained on Genomic Health's website does not constitute part of this proxy statement/prospectus. Genomic Health common stock is publicly traded on The Nasdaq Stock Market LLC under the ticker symbol "GHDX." Additional information about Genomic Health is included in documents incorporated by reference in this proxy statement/prospectus. Please see the section entitled "Where You Can Find More Information" beginning on page 160.

Spring Acquisition Corp.

        Spring Acquisition Corp, a wholly owned subsidiary of Exact Sciences, is a Delaware corporation incorporated on July 26, 2019 for the purpose of effecting the merger. Spring Acquisition Corp. has not conducted any activities other than those incidental to its formation and the matters contemplated by the merger agreement. The principal executive offices of Spring Acquisition Corp. are located at 441 Charmany Drive, Madison, Wisconsin 53719 and its telephone number is (608) 535-8815.

The Merger

        A summary of the terms and conditions of the merger are contained in the merger agreement, a copy of which is attached as Annex A to this proxy statement/prospectus. We encourage you to read the merger agreement carefully and in its entirety, as it is the legal document that governs the merger.

        On July 28, 2019, Exact Sciences, Genomic Health and Merger Sub entered into the merger agreement, which provides that, subject to the terms and conditions of the merger agreement and in accordance with the DGCL, Merger Sub will merge with and into Genomic Health, with Genomic Health continuing as the surviving corporation and a wholly owned subsidiary of Exact Sciences.

Merger Consideration

        At the completion of the merger, each share of Genomic Health common stock issued and outstanding immediately prior to the completion of the merger (other than (1) shares held by Genomic Health as treasury stock, Exact Sciences, or any subsidiaries of Genomic Health or Exact Sciences and (2) shares held by a holder who has properly exercised and perfected (and not effectively withdrawn or lost) such holder's demand for appraisal rights under the DGCL, both of which are collectively referred to herein as excluded shares) will be converted into the right to receive (a) $27.50 in cash, without interest, which is referred to as the cash consideration, plus (b) a fraction of a share of Exact Sciences common stock equal to the quotient obtained by dividing $44.50 by the average of the volume-weighted average prices per share of Exact Sciences common stock on Nasdaq (as reported by Bloomberg L.P. or, if not reported on Bloomberg L.P., in another authoritative source mutually selected by Genomic Health and Exact Sciences) on each of the 15 consecutive trading days ending with the trading day immediately prior to the closing date, which is referred to as the Exact Sciences stock price, subject to

adjustment based on a two-way collar mechanism described below, which is referred to as the stock consideration. The cash and Exact Sciences stock payable in exchange for each such share of Genomic Health common stock are collectively referred to as the merger consideration. The fraction of a share of Exact Sciences common stock into which each share of Genomic Health common stock (other than excluded shares) will be converted is referred to as the exchange ratio. The exchange ratio will be calculated based upon the Exact Sciences stock price. If the Exact Sciences stock price is greater than $98.79 but less than $120.75, the exchange ratio will be equal to the quotient of (i) $44.50 divided by (ii) the Exact Sciences stock price. If the Exact Sciences stock price is equal to or less than $98.79 or equal to or greater than $120.75, then a two-way collar mechanism will apply, pursuant to which (x) if the Exact Sciences stock price is equal to or greater than $120.75, the exchange ratio will be fixed at 0.36854 and (y) if the Exact Sciences stock price is equal to or less than $98.79, the exchange ratio will be fixed at 0.45043. Upon the completion of the merger, based on minimum and maximum exchange ratios of 0.36854 and 0.45043, the estimated number of shares of Exact Sciences common stock issuable as a portion of the merger consideration is between 14.2 million shares and 17.4 million shares, which will result in former Genomic Health stockholders holding approximately 8.7% to 10.4% of the outstanding fully diluted Exact Sciences common stock, based on the number of outstanding shares of common stock and outstanding stock-based awards of Genomic Health and Exact Sciences as of October 2, 2019 and assuming a closing date of October 2, 2019. For more details on the shares of Exact Sciences common stock and other consideration to be received by Genomic Health stockholders, see "The Merger Agreement—Merger Consideration" beginning on page 88.

        All fractional shares of Exact Sciences common stock that would otherwise be issued to a Genomic Health stockholder of record as part of the merger consideration will be aggregated to create whole shares of Exact Sciences common stock that will be issued to Genomic Health stockholders as part of the merger consideration. If a fractional share of Exact Sciences common stock remains payable to a Genomic Health stockholder of record after aggregating all fractional shares of Exact Sciences common stock payable to such Genomic Health stockholder, then such stockholder will be paid, in lieu of such remaining fractional share of Exact Sciences common stock, an amount in cash, without interest, rounded down to the nearest cent, equal to the product of (1) the amount of the fractional share interest in a share of Exact Sciences common stock to which such holder would otherwise be entitled (rounded to five decimal places) and (2) the Exact Sciences stock price.

Treatment of Genomic Health Equity Awards

•

Director Restricted Stock Unit Awards.  At the effective time of the merger, each Genomic Health RSU award held by a non-employee director that is outstanding immediately prior to the effective time of the merger will, to the extent not vested, become fully vested and canceled in consideration for the right to receive the merger consideration in respect of each underlying share of Genomic Health common stock.



•

Employee Restricted Stock Unit Awards.  At the effective time of the merger, each Genomic Health RSU award not held by a non-employee director that is outstanding immediately prior to the effective time of the merger will be converted into a restricted stock unit award of Exact Sciences subject to the same terms and conditions, provided that, in the event the holder experiences a qualifying termination upon or within 18 months following the effective time of the merger, the converted award will accelerate and immediately become vested (i) in full if the holder is a participant in Genomic Health's Severance Plans for Executive Management or (ii) with respect to the portion of the award that is scheduled to vest during the 12 month period immediately following the date of the qualifying termination if the holder is not a participant in Genomic Health's Severance Plans for Executive Management.



•

Director Options.  At the effective time of the merger, each Genomic Health stock option held by a non-employee director, whether vested or unvested, that is outstanding immediately prior to

the effective time of the merger will be canceled and converted into the right to receive the merger consideration in respect of each net option share subject to such stock option.

•

Vested Employee Options.  At the effective time of the merger, each vested Genomic Health stock option not held by a non-employee director that is outstanding immediately prior to the effective time of the merger will be canceled and converted into the right to receive the merger consideration in respect of each net option share subject to such stock option.



•

Unvested Employee Options.  At the effective time of the merger, each unvested Genomic Health stock option not held by a non-employee director that is outstanding immediately prior to the effective time of the merger will be converted into an Exact Sciences stock option, subject to the same terms and conditions, provided that, in the event the holder experiences a qualifying termination upon or within 18 months following the effective time of the merger, the converted stock option will accelerate and immediately become vested (i) in full if the holder is a participant in Genomic Health's Severance Plans for Executive Management or (ii) with respect to the portion of such award that is scheduled to vest during the 12 month period immediately following the date of the qualifying termination if the holder is not a participant in Genomic Health's Severance Plans for Executive Management.

        The merger agreement provides that the current June 1, 2019 to November 29, 2019 offering period ongoing as of the date of the merger agreement will be the final offering period under the ESPP, and that each ESPP participant's accumulated contributions under the ESPP will be used to purchase shares of Genomic Health common stock in accordance with the ESPP on the earlier of (i) the end of the offering period and (ii) the trading date that is four business days prior to the closing date. The merger agreement also provides that (A) no additional purchase rights will be granted under the ESPP, (B) participants in the ESPP will be prohibited from increasing their payroll deductions from those in effect on the date of the merger agreement, (C) no individual may make separate non-payroll contributions to the ESPP, (D) no new individual may commence participation in the ESPP and (E) the ESPP will be terminated immediately prior to the effective time of the merger.

Recommendation of the Genomic Health Board of Directors

        After careful consideration of various factors described in "The Merger—Genomic Health Board of Directors' Recommendation and Reasons for the Merger" beginning on page 57, the Genomic Health Board unanimously recommends that holders of common stock vote:

•

"FOR" the merger proposal;



•

"FOR" the merger-related compensation proposal; and



•

"FOR" the adjournment proposal.

Opinion of Genomic Health's Financial Advisor

        Goldman Sachs & Co. LLC, which is referred to as Goldman Sachs, delivered its opinion to the Genomic Health Board that, as of July 28, 2019 and based upon and subject to the factors and assumptions set forth therein, the aggregate of $27.50 in cash and the shares of Exact Sciences common stock equal to the exchange ratio to be paid to the holders (other than Exact Sciences and its affiliates) of shares of Genomic Health common stock pursuant to the merger agreement was fair from a financial point of view to such holders.

        The full text of the written opinion of Goldman Sachs, dated July 28, 2019, which sets forth assumptions made, procedures followed, matters considered and limitations on the review undertaken in connection with the opinion, is attached to this proxy statement/prospectus as Annex E. Goldman Sachs provided advisory services and its opinion for the information and assistance of the Genomic

Health Board in connection with its consideration of the merger. The Goldman Sachs opinion is not a recommendation as to how any holder of Genomic Health common stock should vote with respect to the merger or any other matter.

Interests of Certain Persons in the Merger

        In considering the recommendation of the Genomic Health Board that you vote to adopt the merger agreement, you should be aware that Genomic Health's directors and executive officers have interests in the merger that are different from, or in addition to, those of Genomic Health stockholders generally. These interests include:

•

Each of Genomic Health's directors and executive officers holds outstanding Genomic Health equity awards which will be subject to the following treatment:



•

Restricted Stock Unit Awards. At the effective time of the merger, (i) each Genomic Health RSU award held by a non-employee director that is outstanding immediately prior to the effective time of the merger will become fully vested and canceled in consideration for the right to receive the merger consideration, and (ii) each Genomic Health RSU award that is held by an executive officer that is outstanding immediately prior to the effective time of the merger will be assumed by Exact Sciences and converted into a restricted stock unit award of Exact Sciences subject to the same terms and conditions, provided that the award will accelerate and immediately vest in full in the event that an executive officer is terminated without "cause" or resigns for "good reason" pursuant to the terms of Genomic Health's Severance Plans for Executive Management.



•

Options. At the effective time of the merger, (i) each Genomic Health stock option held by a non-employee director that is outstanding immediately prior to the effective time of the merger and each vested Genomic Health stock option held by an executive officer that is outstanding immediately prior to the effective time of the merger will be canceled in consideration for the right to receive the merger consideration in respect of each net option share, and (ii) each unvested Genomic Health stock option held by an executive officer that is outstanding immediately prior to the effective time of the merger will be assumed by Exact Sciences and converted into an Exact Sciences option subject to the same terms and conditions as the Genomic Health stock option, provided that the option will accelerate and immediately vest in full in the event that an executive officer is terminated without "cause" or resigns for "good reason" pursuant to the terms of Genomic Health's Severance Plans for Executive Management.



•

Each of Genomic Health's executive officers is a participant in one of Genomic Health's Severance Plans for Executive Management, which provide that, in the event the executive officer is terminated without cause or resigns for good reason within the period beginning with the execution of a definitive agreement that results in a change in control within 3 months and ending 18 months following a change in control, he or she will be entitled to (i) an amount equal to either 250% or 150% of their base salary and target annual bonus, (ii) a pro-rated bonus at target performance, (iii) benefits continuation for either 24 or 18 months, (iv) full accelerated vesting of all outstanding equity awards and (v) accrued and unpaid compensation.

        Members of the Genomic Health Board were aware of and considered these interests, among other matters, in evaluating and negotiating the merger agreement and the merger, and in recommending to Genomic Health stockholders that the merger agreement be adopted. For more information, see the sections entitled "The Merger—Background of the Merger" beginning on page 46 and "The Merger—Genomic Health Board of Directors' Recommendation and Reasons for the Merger" beginning on page 57. These interests are described in more detail below and in the section entitled "The Merger—Interests of Certain Persons in the Merger" beginning on page 75.

Information about the Genomic Health Stockholders' Meeting

Time, Place and Purpose of the Special Meeting

        The special meeting to consider and vote upon the adoption of the merger agreement and related matters, which is referred to as the special meeting, will be held at 10:00 a.m., Pacific Time, on Thursday, November 7, 2019 at the offices of Pillsbury Winthrop Shaw Pittman LLP, 2550 Hanover Street, Palo Alto, California 94304.

        At the special meeting, the stockholders will be asked to consider and vote upon (1) the merger proposal, (2) the merger-related compensation proposal and (3) the adjournment proposal.

Record Date and Quorum

        You are entitled to receive notice of, and to vote at, the special meeting if you are an owner of record of shares of Genomic Health common stock as of the close of business on October 2, 2019, the record date. On the record date, there were 37,546,245 shares of Genomic Health common stock outstanding and entitled to vote. Stockholders will have one vote on all matters properly coming before the special meeting for each share of common stock owned by such stockholders on the record date.

        The Genomic Health bylaws provide that the holders of a majority of the shares of common stock issued and outstanding and entitled to vote, present in person or represented in proxy, will constitute a quorum for the transaction of business at the special meeting.

Vote Required

        The merger proposal requires the affirmative vote of holders of a majority of the shares of Genomic Health common stock outstanding and entitled to vote (in person or by proxy) at the special meeting. If a Genomic Health stockholder present in person at the special meeting abstains from voting, responds by proxy with an "abstain" vote, is not present in person at the special meeting and does not respond by proxy or does not provide their bank, brokerage firm or other nominee with instructions, as applicable, it will have the effect of a vote cast "AGAINST" such proposal.

        The merger-related compensation proposal requires the affirmative vote of holders of a majority of the shares of Genomic Health common stock represented (in person or by proxy) at the special meeting and entitled to vote on the proposal, assuming a quorum. If a Genomic Health stockholder present in person at the special meeting abstains from voting, or responds by proxy with an "abstain" vote, it will have the same effect as a vote cast "AGAINST" for such proposal. If a stockholder is not present in person at the special meeting and does not respond by proxy or does not provide their bank, brokerage firm or other nominee with instructions, as applicable, it will have no effect on the outcome of the merger-related compensation proposal (assuming a quorum is present).

        The adjournment proposal requires the affirmative vote of holders of a majority of the shares of Genomic Health common stock represented (in person or by proxy) at the special meeting and entitled to vote on the proposal, regardless of whether a quorum is present. If a Genomic Health stockholder present in person at the special meeting abstains from voting, or responds by proxy with an "abstain" vote, it will have the same effect as a vote cast "AGAINST" for such proposal. If a stockholder is not present in person at the special meeting and does not respond by proxy or does not provide their bank, brokerage firm or other nominee with instructions, as applicable, it will have no effect on the vote count for such proposal (regardless of whether a quorum is present).

Proxies and Revocations

        Each stockholder of record entitled to vote at the special meeting may submit a proxy by telephone, over the Internet, by properly executing and delivering the enclosed proxy card in the

accompanying prepaid reply envelope or may vote in person by appearing at the special meeting. If your shares of common stock are held in "street name" through a bank, brokerage firm or other nominee, you should instruct your bank, brokerage firm or other nominee on how to vote your shares of common stock using the instructions provided by your bank, brokerage firm or other nominee.

        If you are a record holder, you may change or revoke your vote before your proxy is voted at the special meeting as described herein. You may do this in one of the following four ways: (1) by duly submitting a subsequently dated proxy relating to the same shares of Genomic Health common stock by telephone or via the Internet (i.e., your most recent duly submitted voting instructions will be followed); (2) by sending to Genomic Health's Secretary (at Genomic Health's principal executive offices) a signed written notice of revocation bearing a later date than the proxy, stating that the proxy is revoked; (3) by submitting a properly completed proxy card relating to the same shares of Genomic Health common stock with a later date; or (4) by attending the special meeting and voting in person. If you choose any of the first three methods, you must take the described action no later than the beginning of the special meeting. For more information on revocations of proxies, see "The Special Meeting—Revocability of Proxies" beginning on page 117.

Voting by Genomic Health's Directors and Executive Officers

        At the close of business on October 2, 2019, Genomic Health directors and executive officers and their affiliates were entitled to vote 9,791,074 shares of Genomic Health common stock. Genomic Health currently expects its directors and executive officers to vote their shares in favor of all proposals to be voted on at the special meeting, but no director or executive officer has entered into any agreement obligating him or her to do so other than Julian C. Baker and Felix J. Baker, who have entered into voting agreements. The number of shares reflected above does not include shares underlying outstanding RSU awards or stock options. For information with respect to RSU awards and stock options, see "The Merger Agreement—Treatment of Genomic Health Equity Awards" beginning on page 90. For information with respect to the voting agreements, see "The Merger—Voting Agreements" beginning on page 81.

Voting Agreements

        Concurrently with the execution of the merger agreement, Felix J. Baker and Julian C. Baker, directors of Genomic Health, and certain funds advised by an entity affiliated with Felix J. Baker and Julian C. Baker, entered into voting agreements with Exact Sciences pursuant to which, among other things and subject to the terms and conditions therein, such stockholders agreed, in their capacities as holders of shares of Genomic Health common stock, to vote all shares of Genomic Health common stock beneficially owned by such stockholders at the time of the stockholder vote on the merger in favor of adoption of the merger agreement and the approval of the transactions contemplated by the merger agreement, including the merger, and any other matter necessary to consummate such transactions, and not to vote in favor of, or tender their shares of Genomic Health common stock into, any competing offer or acquisition proposal. In addition, each stockholder party to any such voting agreement waived appraisal rights and provided an irrevocable proxy to Exact Sciences to vote in favor of the merger, including by voting for the adoption of the merger agreement. As of October 2, 2019, approximately 25.1% of the outstanding shares of Genomic Health common stock are subject to the voting agreements described herein.

Regulatory Approvals

        Under the HSR Act and related rules, certain transactions, including the merger, may not be completed until notifications have been given and information furnished to the Antitrust Division of the United States Department of Justice, which is referred to as the Antitrust Division, and the United States Federal Trade Commission, which is referred to as the FTC, and all statutory waiting period

requirements have been satisfied. Completion of the merger is subject to the expiration or earlier termination of the applicable waiting period under the HSR Act. Exact Sciences and Genomic Health each filed their respective HSR Act notification forms on August 9, 2019. The required 30-day waiting period under the HSR Act expired at 11:59 p.m., Eastern time, on September 9, 2019.

        There can be no assurance that a challenge to the merger on antitrust grounds will not be made or, if such a challenge is made, that it would not be successful.

        See "The Merger—Regulatory Approvals" beginning on page 81.

Conditions to Completion of the Merger

        In addition to the approval of the merger proposal by Genomic Health stockholders and the expiration or termination of the applicable waiting period under the HSR Act, each party's obligation to complete the merger is also subject to the satisfaction or waiver (to the extent permitted under applicable law) of certain other conditions, including the effectiveness of the registration statement on Form S-4 of which this proxy statement/prospectus forms a part (and the absence of any stop order, or pending proceedings seeking a stop order, by the SEC), approval of the listing on Nasdaq of the Exact Sciences common stock to be used for a portion of the merger consideration, the absence of an injunction or law that has the effect of enjoining or otherwise prohibiting the merger, the accuracy of the representations and warranties of the parties under the merger agreement (subject to the materiality standards set forth in the merger agreement), the performance by the parties of their respective covenants and obligations under the merger agreement in all material respects and delivery of officer certificates by the parties certifying satisfaction of certain of the conditions described above.

        The parties expect to complete the merger after all of the conditions to the merger in the merger agreement are satisfied or waived. For a more complete description of the conditions to the merger, see "The Merger Agreement—Conditions to the Merger" beginning on page 107.

Timing of the Merger

        The transaction is expected to be completed by the end of 2019. Neither Exact Sciences nor Genomic Health can predict, however, the actual date on which the transaction will be completed because it is subject to conditions beyond each company's control, including obtaining the necessary regulatory approvals. For a more complete description of the conditions to the merger, see "The Merger Agreement—Conditions to the Merger" beginning on page 107.

No Solicitation

        As more fully described in this proxy statement/prospectus and in the merger agreement, and subject to the exceptions summarized below, Genomic Health has agreed that between July 28, 2019 and the earlier of the completion of the merger and the termination of the merger agreement (1) it, its subsidiaries and its and their respective officers and directors will immediately cease and terminate, and will use reasonable best efforts to cause its and their respective other representatives to immediately cease and terminate all existing discussions, negotiations and communications with any person or entity with respect to any "acquisition proposal" (as defined in the merger agreement), involving Genomic Health, including proposals to acquire 15% or more of the Genomic Health voting power, consolidated assets, revenues or net income; (2) Genomic Health will not, and will not authorize, and will use its reasonable best efforts not to permit any of its representatives to, directly or indirectly, initiate, seek, solicit, knowingly facilitate, knowingly encourage or knowingly induce or knowingly take any other action reasonably expected to lead to an acquisition proposal, engage in negotiations or discussions with or provide any non-public information or non-public data to any person or entity relating to or for the purpose of encouraging or facilitating an acquisition proposal or grant any waiver or release under any standstill, confidentiality or other similar agreement (unless the Genomic Health Board determines

in good faith that the failure to grant such waiver or release would be inconsistent with its fiduciary duties under applicable law); (3) Genomic Health will not provide access (and will terminate any such access) to any third party to any data room containing any information of Genomic Health or any of its subsidiaries; and (4) Genomic Health will demand the return or destruction of all confidential, non-public information and materials that have been provided to third parties that have entered into confidentiality agreements relating to a possible acquisition proposal with Genomic Health or any of its subsidiaries since July 1, 2018.

        The merger agreement includes certain exceptions to the non-solicitation covenant such that, prior to obtaining the stockholder approval, Genomic Health may participate in discussions and negotiations concerning such acquisition proposal if the Genomic Health Board determines in good faith, after consultation with outside financial advisors and outside legal counsel, that such acquisition proposal constitutes or is reasonably likely to constitute or result in a "superior proposal" (as defined in the merger agreement). Also, the Genomic Health Board may, subject to complying with certain specified procedures, including providing Exact Sciences with a good faith opportunity to negotiate and, in certain circumstances, payment of a termination fee as described below, (1) change its recommendation in favor of the merger and the other transactions contemplated by the merger agreement, or terminate the merger agreement in order to enter into a definitive agreement regarding an unsolicited acquisition proposal that is determined to be a superior proposal, or (2) change its recommendation in favor of the merger and the other transactions contemplated by the merger agreement in response to an "intervening event" (as defined in the merger agreement) that becomes known after the date of the merger agreement but prior to the Genomic Health stockholder approval, in each case, to the extent failure to do so would be inconsistent with its fiduciary duties under applicable law.

        For a more complete description of the limitations on solicitation of acquisition proposals from third parties and the ability of the Genomic Health Board to change its recommendation for the transaction, see "The Merger Agreement—Covenants and Agreements—No Solicitation" beginning on page 101.

Termination of the Merger Agreement; Termination Fee

        The merger agreement may be terminated by mutual written consent of Exact Sciences and Genomic Health at any time prior to the closing. In addition, the merger agreement may be terminated as follows:

•

by either Exact Sciences or Genomic Health if:



•

the merger has not been completed on or before 5:00 p.m. (New York time) on April 28, 2020 (subject to extension through July 28, 2020, if all conditions other than the antitrust-related condition are or would be satisfied as of such date), which is referred to as the termination date, except where the party seeking to terminate this agreement for this reason has committed a material breach of any of its obligations under the merger agreement and such material breach was the principal cause of or principally resulted in the failure of the completion of the merger on or before such date, which termination right is referred to as the end date termination right;



•

any governmental authority has issued or entered any restraint that would permanently restrain, enjoin or otherwise prohibit the completion of the merger, and the imposition of such restraint has become final and nonappealable, except where the party seeking to terminate this agreement for this reason has committed a material breach of its obligations under the merger agreement to cause the consummation of the merger and such material breach was the principal cause of or principally resulted in issuance of such restraint;

•

the stockholder approval has not been obtained at the special meeting or at any adjournment or postponement of such meeting; or



•

the other party breaches or fails to perform any of its representations, warranties, covenants or other agreements in the merger agreement, which breach or failure to perform would result in the failure of a condition related to the accuracy of the other party's representations and warranties or performance of covenants in the merger agreement, subject to certain materiality thresholds and rights to cure and other limitations (this termination right is referred to as the breach termination right);



•

by Genomic Health if prior to stockholder approval, Genomic Health enters into a definitive agreement with respect to a superior proposal, as described further in "The Merger Agreement—Covenants and Agreements—No Solicitation" beginning on page 101, provided that Genomic Health pays to Exact Sciences the termination fee; or



•

by Exact Sciences if prior to stockholder approval, Genomic Health (1) makes an adverse recommendation change, as described further in "The Merger Agreement—Termination" beginning on page 109, or fails to include in this proxy statement/prospectus the Genomic Health Board's recommendation for the merger, or (2) fails to publicly reaffirm the Genomic Health Board's recommendation for the merger within 10 business days of public announcement of certain competing acquisition proposals, or fails to recommend against an acquisition proposal in the form of a tender or exchange offer within 10 business days of commencement of such offer (this termination right is referred to as the recommendation change termination right).

        If the merger agreement is terminated as described above, the merger agreement will be null and void and of no effect, without liability on the part of any party and each party's rights and obligations will cease, subject to certain exceptions, including that:

•

no termination will relieve any party of any liability or damages resulting from any knowing and intentional breach of its obligations under the merger agreement prior to such termination or fraud in the making of the representations and warranties set forth in the merger agreement; and



•

the confidentiality agreement entered into by Exact Sciences and Genomic Health in connection with entering into the merger, the effect of termination, termination fees, amendment, extensions and waiver provisions and certain general provisions of the merger agreement, including provisions relating to interpretation and construction, will survive any termination of the merger agreement.

        The merger agreement provides for payment of a termination fee by Genomic Health to Exact Sciences of $92.4 million in connection with a termination of the merger agreement under the following circumstances:

•

if (1) Exact Sciences terminates the merger agreement pursuant to the breach termination right or (2) either party terminates the merger agreement pursuant to the end date termination right or failure of Genomic Health to obtain the stockholder approval, and, in any such case, after the execution of the merger agreement and prior to the termination, an acquisition proposal (with regard to 50% or more of the voting power, consolidated assets, revenues or net income of Genomic Health) is publicly disclosed or, in certain circumstances, otherwise made known to the Genomic Health Board and not withdrawn (publicly, if publicly disclosed) and Genomic Health consummates an acquisition proposal or enters into a definitive agreement with respect to any acquisition proposal within 12 months of the termination that is subsequently consummated;



•

if Genomic Health terminates the merger agreement in order to enter into a definitive agreement with respect to a superior proposal; or

•

if Exact Sciences terminates the merger agreement pursuant to the recommendation change termination right.

        In no event will the termination fee be payable more than once.

        For a more complete description of each party's termination rights and the related termination fee obligations, see "The Merger Agreement—Termination" beginning on page 109 and "The Merger Agreement—Termination Fee" beginning on page 111.

Appraisal Rights of Genomic Health Stockholders

        Under the DGCL, if the merger is completed, record holders of Genomic Health common stock who do not vote in favor of the merger proposal and who otherwise properly exercise and perfect their appraisal rights will be entitled to seek appraisal for, and obtain payment in cash for the judicially determined fair value of, their shares of common stock, in lieu of receiving the merger consideration. The "fair value" could be higher or lower than, or the same as, the merger consideration. The relevant provisions of the DGCL are included as Annex F to this proxy statement/prospectus. Genomic Health stockholders are encouraged to read these provisions carefully and in their entirety. Moreover, due to the complexity of the procedures for exercising and perfecting the right to seek appraisal, Genomic Health stockholders who are considering exercising and perfecting that right are encouraged to seek the advice of legal counsel. Failure to comply strictly with these provisions may result in loss of the right of appraisal. For a more complete description of Genomic Health stockholders' appraisal rights, see "Appraisal Rights" beginning on page 155.

U.S. Federal Income Tax Consequences

        The exchange of Genomic Health common stock pursuant to the merger will be a taxable transaction for U.S. federal income tax purposes. In general, for U.S. federal income tax purposes, a U.S. holder (as defined in "The Merger—U.S. Federal Income Tax Consequences" beginning on page 82) of Genomic Health common stock who receives the merger consideration in exchange for such U.S. holder's shares of Genomic Health common stock pursuant to the merger will recognize gain or loss in an amount equal to the difference, if any, between (1) the sum of the fair market value of the Exact Sciences common stock and the amount of cash, including cash in lieu of a fractional share of Exact Sciences common stock, received in the merger and (2) such U.S. holder's adjusted tax basis in the shares of Genomic Health common stock exchanged therefor.

        A stockholder that is a non-U.S. holder (as defined in "The Merger—U.S. Federal Income Tax Consequences") will generally not be subject to U.S. federal income tax with respect to the exchange of Genomic Health common stock pursuant to the merger unless such non-U.S. holder has certain connections to the United States, but may be subject to backup withholding tax unless the non-U.S. holder complies with certain certification procedures or otherwise establishes a valid exemption from backup withholding tax.

        In certain circumstances, as the result of application of Section 304 of the Internal Revenue Code of 1986, which is referred to as the Code, a holder of Genomic Health common stock could be treated as receiving a dividend in an amount up to the cash consideration received by such holder in the merger. As a result of the possibility of such deemed dividend treatment, a non-U.S. holder of Genomic Health common stock may be subject to U.S. withholding tax at a rate of 30% (or such lower rate as may be specified by an applicable income tax treaty) with respect to the cash consideration received in the merger. Holders of Genomic Health common stock should consult their own tax advisors regarding the potential application of Section 304 of the Code to the merger.

        For a more complete description of the U.S. federal income tax consequences of the merger, see "The Merger—U.S. Federal Income Tax Consequences" beginning on page 82.

        This proxy statement/prospectus contains a discussion of the material U.S. federal income tax consequences of the merger. This discussion does not address any non-U.S. tax consequences, nor does it pertain to state or local income or other tax consequences. You should consult your own tax advisors regarding the particular U.S. federal income tax consequences of the merger to you in light of your particular circumstances, as well as the particular tax consequences to you of the merger under any state, local or non-U.S. income or other tax laws.

Accounting Treatment

        Exact Sciences prepares its financial statements in accordance with accounting principles generally accepted in the United States, which are referred to as GAAP. The merger will be accounted for as an acquisition of Genomic Health by Exact Sciences under the acquisition method of accounting in accordance with GAAP. Exact Sciences will be treated as the acquirer for accounting purposes.

Litigation Relating to the Merger

        Beginning on September 4, 2019, five actions were filed by purported stockholders of Genomic Health in federal courts in California and Delaware, captioned Wang v. Genomic Health, Inc., et al., Case No. 3:19-cv-05556 (N.D. Cal), Seligman v. Genomic Health, Inc., et al., Case No. 3:19-cv-05710 (N.D. Cal), Rice v. Genomic Health, Inc. et al., Case No. 3:19-cv-05929, Plumley v. Genomic Health, Inc., et al., Case No. 1:19-cv-01719 (D. Del.), and Martak v. Genomic Health, Inc., et al., Case No. 3:19-cv-06065 (N.D. Cal.), alleging claims relating to the merger. The complaints name as defendants Genomic Health and the members of the Genomic Health Board, and the Seligman and Plumley actions also name as defendants Exact Sciences and Merger Sub. The complaints allege, among other things, claims under Section 14(a) and 20(a) of the Exchange Act asserting that the preliminary proxy statement filed by Genomic Health in connection with the merger is materially incomplete and misleading, and the Seligman complaint also alleges claims for breach of fiduciary duty relating to the merger. The Seligman, Plumley and Rice actions seek to allege claims on behalf of a putative class of stockholders of Genomic Health. The complaints purport to seek to enjoin the planned special meeting of Genomic Health's stockholders unless and until the allegedly missing material information is disclosed or, in the event the merger is consummated, to recover damages from the defendants. The defendants believe the claims asserted in these civil actions are without merit.

        For a more detailed description of litigation in connection with the merger, see "The Merger—Litigation Relating to the Merger" beginning on page 87.

Risk Factors

        You should consider all the information contained in or incorporated by reference into this proxy statement/prospectus in deciding how to vote for the proposals presented in this proxy statement/prospectus. In particular, you should carefully consider the risks that are described in the section entitled "Risk Factors" beginning on page 34.

SELECTED HISTORICAL FINANCIAL DATA

SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA OF EXACT SCIENCES

        The following table sets forth selected consolidated financial data of Exact Sciences. The selected historical consolidated financial data of Exact Sciences for the years ended December 31, 2018, 2017, and 2016 and as of December 31, 2018 and 2017 have been derived from Exact Sciences' historical audited consolidated financial statements contained in Exact Sciences' Annual Report on Form 10-K for the year ended December 31, 2018 incorporated by reference into this proxy statement/prospectus. The selected historical consolidated financial data for the years ended December 31, 2015 and 2014 and as of December 31, 2016, 2015 and 2014 have been derived from Exact Sciences' historical audited consolidated financial statements for such years, which have not been incorporated by reference into this proxy statement/prospectus. The selected historical condensed consolidated financial data for Exact Sciences as of and for the six months ended June 30, 2019 and 2018 have been derived from Exact Sciences' unaudited condensed consolidated financial statements contained in Exact Sciences' Quarterly Report on Form 10-Q for the quarter ended June 30, 2019, which is incorporated by reference into this proxy statement/prospectus. In the opinion of the management of Exact Sciences, the unaudited condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and include all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of the financial position and results of operations at these dates and for these periods. Results of interim periods are not necessarily indicative of the results expected for a full year.

        The following selected consolidated financial data is only a summary and is not necessarily indicative of future results. Such financial data should be read together with, and is qualified in its entirety by reference to, Exact Sciences' "Management's Discussion and Analysis of Financial Condition

and Results of Operations" and the unaudited and audited consolidated financial statements and notes thereto incorporated by reference into this proxy statement/prospectus.

SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA OF GENOMIC HEALTH

        The following table sets forth selected consolidated financial data of Genomic Health. The selected consolidated balance sheet data at December 31, 2018 and 2017 and the selected consolidated statements of operations data for each year ended December 31, 2018, 2017 and 2016 have been derived from Genomic Health's audited consolidated financial statements that are included in Genomic Health's Annual Report on Form 10-K for the fiscal year ended December 31, 2018 and incorporated by reference into this proxy statement/prospectus. The selected consolidated balance sheet data at June 30, 2018 has been derived from Genomic Health's unaudited condensed consolidated financial statements not included or incorporated by reference in this proxy statement/prospectus and the selected consolidated balance sheet data at December 31, 2016, 2015, and 2014 and the selected consolidated statements of operations data for the years ended December 31, 2015 and 2014 have been derived from Genomic Health's audited consolidated financial statements not included or incorporated by reference in this proxy statement/prospectus. The selected consolidated balance sheet data at June 30, 2019 and the selected consolidated statements of operations data for the six months ended June 30, 2019 and June 30, 2018 have been derived from Genomic Health's unaudited condensed consolidated financial statements that are included in Genomic Health's Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2019 and incorporated by reference into this proxy statement/prospectus. In the opinion of the management of Genomic Health, the unaudited condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and include all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of the financial position and results of operations at these dates and for these periods. Results of interim periods are not necessarily indicative of the results expected for a full year.

        The following selected consolidated financial data is only a summary and is not necessarily indicative of future results. Such financial data should be read together with, and is qualified in its entirety by reference to, Genomic Health's "Management's Discussion and Analysis of Financial

Condition and Results of Operations" and the unaudited and audited consolidated financial statements and notes thereto incorporated by reference into this proxy statement/prospectus.