UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): August 2, 2019

DECIPHERA PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

(781) 209-6400

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 or Rule 12b-2 of the Securities Exchange Act of 1934.

Emerging growth company  ☑

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☑

On August 2, 2019, Deciphera Pharmaceuticals, Inc. announced its financial results for the quarter ended June 30, 2019. A copy of the press release in connection with the announcement is being furnished as Exhibit 99.1 to this Current Report on Form 8-K.

The information in this Current Report on Form 8-K (including Exhibit 99.1 attached hereto) is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

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EXHIBIT INDEX

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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Exhibit 99.1

Deciphera Pharmaceuticals, Inc. Announces Second Quarter 2019 Financial Results

- Top-line Data from INVICTUS Pivotal Phase 3 Clinical Study of Ripretinib in Fourth-line and Fourth-line Plus Gastrointestinal Stromal Tumor (GIST) Patients Expected this Month -

- Ripretinib Granted Fast Track Designation by the U.S. Food and Drug Administration for Treatment of Patients with Fourth-line and Fourth-line Plus GIST -

- Exclusive License Agreement with Zai Lab Ltd. Established for the Development and Commercialization of Ripretinib in Greater China -

- DCC-3116 Added to Pipeline as Potential First-in-Class Autophagy Inhibitor to Treat Mutant RAS Cancers -

- Ended Second Quarter 2019 with Cash, Cash Equivalents and Marketable Securities of $225 Million -

Waltham, MA – August 2, 2019 – Deciphera Pharmaceuticals, Inc. (NASDAQ:DCPH), a clinical-stage biopharmaceutical company focused on addressing key mechanisms of tumor drug resistance, today announced financial results for the second quarter ended June 30, 2019 and provided an update on clinical and corporate developments.

“In recent months, we’ve made substantial progress across our pipeline of novel candidates from our two Phase 3 GIST trials with ripretinib to the addition of DCC-3116, a potential first-in-class autophagy inhibitor aimed at treating mutant RAS cancers,” said Steve Hoerter, President and Chief Executive Officer of Deciphera. “Later this month, we expect to announce top-line data from the INVICTUS pivotal Phase 3 clinical study, the results of which, if favorable, could serve as the basis for our first new drug application, or NDA, filing. We also recently established our first license agreement for ripretinib outside of the U.S., which we believe reflects the growing recognition that ripretinib has the potential to alter the treatment landscape for patients with GIST.”

Recent Pipeline Updates

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Corporate Updates

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Second Quarter 2019 Financial Results

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About Deciphera Pharmaceuticals

Deciphera Pharmaceuticals (NASDAQ: DCPH) is a clinical-stage biopharmaceutical company focused on improving the lives of cancer patients by tackling key mechanisms of drug resistance that limit the rate and/or durability of response to existing cancer therapies. Our small molecule drug candidates are directed against an important family of enzymes called kinases, known to be directly involved in the growth and spread of many cancers. We use our deep understanding of kinase biology together with a proprietary chemistry library to purposefully design compounds that maintain kinases in a “switched off” or inactivated conformation. These investigational therapies comprise tumor-targeted agents designed to address therapeutic resistance causing mutations and immuno-targeted agents designed to control the activation of immunokinases that suppress critical immune system regulators, such as macrophages. We have used our platform to develop a diverse pipeline of tumor-targeted and immuno-targeted drug candidates designed to improve outcomes for patients with cancer by improving the quality, rate and/or durability of their responses to treatment.

Availability of Other Information About Deciphera Pharmaceuticals

Investors and others should note that Deciphera Pharmaceuticals communicates with its investors and the public using its company website (www.deciphera.com), including but not limited to investor presentations and scientific presentations, Securities and Exchange Commission filings, press releases, public conference calls and webcasts. The information that Deciphera Pharmaceuticals posts on these channels and websites could be deemed to be material information. As a result, Deciphera Pharmaceuticals encourages investors, the media and others interested in Deciphera Pharmaceuticals to review the information that it posts on these channels, including Deciphera Pharmaceuticals’ investor relations website, on a regular basis. This list of channels may be updated from time to time on Deciphera Pharmaceuticals’ investor relations website and may include other social media channels than the ones described above. The contents of Deciphera Pharmaceuticals’ website or these channels, or any other website that may be accessed from its website or these channels, shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended.

Cautionary Note Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding our expectations regarding timing of reporting top-line data from our INVICTUS pivotal Phase 3 clinical study, the potential for ripretinib (DCC-2618) and our other drug candidates (DCC-3116, rebastinib and DCC-3014) based on our kinase switch control inhibitor platform to provide clinical benefit and treat cancers such as GIST and other possible indications, preparations for a possible NDA, pending positive study results, and commercial launch of ripretinib in fourth-line and fourth-line plus GIST, if approved, expectations for timing of filing and activation of an IND for DCC-3116, expectations of timing of data for, and enrollment with respect to, the Company’s rebastinib and DCC-3014 programs and expectations of benefits from the Company’s license agreement with Zai. The words “may,” “will,” “could,” “would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “estimate,” “predict,” “project,” “potential,” “continue,” “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 press release 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, risks and uncertainties related to the delay of any current or

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planned clinical studies or the development of our drug candidates, including ripretinib, rebastinib, DCC-3014 and DCC-3116, our advancement of multiple early-stage and later-stage efforts, our ability to successfully demonstrate the efficacy and safety of our drug candidates including in later-stage studies, the preclinical and clinical results for our drug candidates, which may not support further development of such drug candidates, our efforts to scale up and manage drug product manufacturing, our ability to implement commercial readiness, actions of regulatory agencies, any or all of which may affect the initiation, timing and progress of clinical studies and other risks identified in our SEC filings, including our Quarterly Report on Form 10-Q for the quarter ended March 31, 2019, and subsequent filings with the SEC. We caution you not to place undue reliance on any forward-looking statements, which speak only as of the date they are made. We disclaim 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. Any forward-looking statements contained in this press release represent our views only as of the date hereof and should not be relied upon as representing its views as of any subsequent date. We explicitly disclaim any obligation to update any forward-looking statements.

CONSOLIDATED BALANCE SHEETS

(In thousands)

(Unaudited)

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CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS

(In thousands, except share and per share data)

(Unaudited)

Contacts:

Investor Relations:

Jen Robinson

Deciphera Pharmaceuticals, Inc.

jrobinson@deciphera.com

781-906-1112

Media:

David Rosen

Argot Partners

David.Rosen@argotpartners.com

212-600-1902

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