UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14D-9

(Rule 14d-101)

SOLICITATION/RECOMMENDATION STATEMENT

UNDER SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934

Deciphera Pharmaceuticals, Inc.

(Name of Subject Company)

Deciphera Pharmaceuticals, Inc.

(Name of Person(s) Filing Statement)

COMMON STOCK, PAR VALUE $0.01 PER SHARE

(Title of Class of Securities)

24344T101

(CUSIP Number of Class of Securities)

Steven L. Hoerter

President & Chief Executive Officer

Deciphera Pharmaceuticals, Inc.

200 Smith Street

Waltham, MA 02451

(781) 209-6400

With copies to:

Stuart M. Cable, Esq.

Lisa R. Haddad, Esq.

James Ding, Esq.

Richard A. Hoffman, Esq.

Sarah Ashfaq, Esq.

Goodwin Procter LLP

100 Northern Avenue

Boston, Massachusetts 02210

(617) 570-1000

☒ Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

This Schedule 14D-9 filing relates solely to preliminary communications made before the commencement of a planned cash tender offer (the “Offer”) by Topaz Merger Sub, Inc., a Delaware corporation (“Merger Sub”) and a wholly owned subsidiary of Ono Pharmaceutical Co., Ltd., a Japanese company (kabushiki kaishi) (“Parent”), to acquire all of the issued and outstanding shares of common stock, par value $0.01 per share, of Deciphera Pharmaceuticals, Inc., a Delaware corporation (the “Company” or “Deciphera”), to be commenced pursuant to the Agreement and Plan of Merger, dated as of April 29, 2024, by and among Parent, Merger Sub and the Company (the “Merger Agreement”). Upon the consummation of the Offer, Merger Sub will merge with and into the Company (the “Merger”) pursuant to Section 251(h) of the Delaware General Corporation Law, with the Company as the surviving corporation. This Schedule 14D-9 filing consists of the following documents relating to the proposed Offer and Merger:

• Exhibit 99.1: Postings by the Company and Steven L. Hoerter, President and Chief Executive Officer of the Company, via LinkedIn on April 29, 2024 (after 5:30 pm EST)

• Exhibit 99.2: Posting by the Company on X on April  29, 2024 (after 5:30 p.m. EST)

• Exhibit 99.3: Joint Press Release issued by Ono Pharmaceutical Co., Ltd. and Deciphera Pharmaceuticals, Inc. on April 30, 2024

Cautionary Note Regarding Forward-Looking Statements

This document contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding the proposed acquisition of Deciphera by Ono, the expected timetable for completing the transaction, Deciphera’s future financial or operating performance, the expectations and timing regarding the potential for Deciphera’s preclinical and/or clinical stage pipeline assets to be first-in-class and/or best-in-class treatments, and the ability of Deciphera to become a company with multiple approved medicines. The words “may,” “will,” “could,” “would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “estimate,” “predict,” “project,” “potential,” “continue,” “seek,” “target” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements in this document are based on management’s current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this press release, including, without limitation: (i) risks associated with the timing of the closing of the proposed transaction, including the risks that a condition to closing would not be satisfied within the expected timeframe or at all or that the closing of the proposed transaction will not occur; (ii) uncertainties as to how many of Deciphera’s stockholders will tender their shares in the offer; (iii) the possibility that a governmental entity may prohibit, delay or refuse to grant approval for the consummation of the transaction; (iv) the possibility that competing offers will be made; (v) the outcome of any legal proceedings that may be instituted against the parties and others related to the merger agreement; (vi) unanticipated difficulties or expenditures relating to the proposed transaction, the response of business partners and competitors to the announcement of the proposed transaction, and/or potential difficulties in employee retention as a result of the announcement and pendency of the proposed transaction; (vii) Deciphera’s ability to successfully demonstrate the efficacy and safety of its drug or drug candidates, and the preclinical or clinical results for its product candidates, which may not support further development of such product candidates; (viii) comments, feedback and actions of regulatory agencies; (ix) Deciphera’s ability to commercialize QINLOCK^® and execute on its marketing plans for any drugs or indications that may be approved in the future; (x) the inherent uncertainty in estimates of patient populations, competition from other products, Deciphera’s ability to obtain and maintain reimbursement for any approved product and the extent to which patient assistance programs are utilized; and (xi) other risks identified in Deciphera’s SEC filings, including Deciphera’s Annual Report on Form 10-K for the year ended December 31, 2023, and subsequent filings with the SEC. Deciphera cautions you not to place undue reliance on any forward-looking statements, which speak only as of the date they are made. Deciphera disclaims any obligation to publicly update or revise any such statements to reflect any change in expectations or in events, conditions or circumstances on which any such statements may be based, or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.

The Deciphera logo and the QINLOCK^® word mark and logo are registered trademarks and the Deciphera word mark is a trademark of Deciphera Pharmaceuticals, LLC.

Additional Information and Where to Find It

The tender offer referred to in this document has not yet commenced. This document is for informational purposes only and is neither an offer to purchase nor a solicitation of an offer to sell shares, nor is it a substitute for the tender offer materials that Parent or Merger Sub will file with the SEC upon commencement of the tender offer. At the time the tender offer is commenced, Ono and its acquisition subsidiary will cause to be filed a tender offer statement on Schedule TO with the SEC, and Deciphera will file a solicitation/recommendation statement on Schedule 14D-9 with respect to the tender offer. THE TENDER OFFER STATEMENT (INCLUDING AN OFFER TO PURCHASE, A RELATED LETTER OF TRANSMITTAL AND OTHER OFFER DOCUMENTS) AND THE SOLICITATION/RECOMMENDATION STATEMENT WILL CONTAIN IMPORTANT INFORMATION THAT SHOULD BE READ CAREFULLY AND CONSIDERED BY DECIPHERA’S STOCKHOLDERS BEFORE ANY DECISION IS MADE WITH RESPECT TO THE TENDER OFFER. Both the tender offer statement and the solicitation/recommendation statement will be mailed to Deciphera’s stockholders free of charge. A free copy of the tender offer statement and the solicitation/recommendation statement will also be made available to all stockholders of Deciphera by accessing www.deciphera.com or by contacting Investor Relations at deciphera@argotpartners.com. In addition, the tender offer statement and the solicitation/recommendation statement (and all other documents filed with the SEC) will be available at no charge on the SEC’s website: www.sec.gov, upon filing with the SEC.

DECIPHERA’S STOCKHOLDERS ARE ADVISED TO READ THE SCHEDULE TO AND THE SCHEDULE 14D-9, AS EACH MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME, AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC WHEN THEY BECOME AVAILABLE BEFORE THEY MAKE ANY DECISION WITH RESPECT TO THE TENDER OFFER, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION AND THE PARTIES THERETO.