Deciphera Pharmaceuticals, Inc. Reports Updated Data from Ongoing Phase 1 Clinical Trial of DCC-2618 at 2018 American Association for Cancer Research (AACR) Annual Meeting

– Pharmacokinetic (PK), Safety, and Tolerability Profile of DCC-2618
in a Phase 1 Clinical Trial Supports 150mg QD Selected for a Pivotal
Phase 3 Study in Gastrointestinal Stromal Tumor (GIST) –

WALTHAM, Mass.–(BUSINESS WIRE)–$DCPH #AACR18–Deciphera Pharmaceuticals, Inc. (NASDAQ:DCPH), a clinical-stage
biopharmaceutical company focused on addressing key mechanisms of tumor
drug resistance, today announced the presentation of updated data from
its ongoing Phase 1 clinical trial of DCC-2618, the Company’s broad
spectrum KIT and PDGFRα inhibitor, in patients with gastrointestinal
stromal tumors (GIST). Filip Janku, M.D., Ph.D., Assistant Professor,
The University of Texas MD Anderson Cancer Center presented the poster
titled “Pharmacokinetic (PK), safety, and tolerability profile of
DCC-2618 in a phase 1 trial supports 150 mg QD (once daily) selected for
a pivotal phase 3 trial in gastrointestinal stromal tumors (GIST)” at
the 2018 American Association for Cancer Research (AACR) Annual Meeting
in Chicago, IL. The poster includes an assessment of the safety and
tolerability profile of DCC-2618 in 100 GIST patients treated at the
recommended Phase 2 dose (RP2D) of 150 mg QD, which supports the
selection of this dose for the ongoing pivotal, randomized Phase 3
INVICTUS study (NCT03353753).

“The data presented at AACR provides a robust assessment of the safety
and tolerability profile of DCC-2618 in GIST patients at the 150 mg QD
dose selected for the INVICTUS pivotal Phase 3 study in fourth-line and
fourth line plus GIST, which we initiated in January 2018,” said Michael
D. Taylor, Ph.D., President and Chief Executive Officer of Deciphera.
“If successful, the INVICTUS study could serve as the basis for a New
Drug Application (NDA), providing a much-needed therapeutic option for
these patients for whom there are no approved treatment options. We also
plan to initiate a second Phase 3 registration study later this year,
evaluating DCC-2618 in second-line GIST patients who have progressed, or
are intolerant to front-line therapy with imatinib.”

The poster presentation includes the following highlights:

  • Safety and tolerability of DCC-2618 on 100 GIST patients treated at
    the 150 mg QD dose out of the total of 169 patients treated with
    DCC-2618, as of the cut-off date of January 18, 2018.
  • As of March 19, 2018, 81 of 137 GIST patients enrolled at the cut-off
    date and treated at 100 mg or more per day, remained on study
    treatment. In addition, 46 patients were treated for more than 6
    months, including 10 patients who were treated for more than 12 months.
  • Employing a population pharmacokinetic (PK) model based on steady
    state exposure to DCC-2618 and the active metabolite, DP-5439,
    increasing doses of DCC-2618 resulted in dose proportional increases
    in the combined exposure.
  • Preliminary data from the 12 GIST patients dose escalated from 150 mg
    QD to 150 mg BID following progression by RECIST (Response Evaluation
    Criteria in Solid Tumors) are immature and do not currently support a
    conclusion regarding a benefit from intra-patient dose escalation.
  • Based on the 100 GIST patients treated at the RP2D dose of 150 mg QD,
    DCC-2618 was well-tolerated, supporting the use of this dose in the
    pivotal, randomized Phase 3 trial, INVICTUS (NCT03353753).

About DCC-2618

DCC-2618 is a KIT and PDGFRα kinase switch control inhibitor in clinical
development for the treatment of KIT and/or PDGFRα-driven cancers,
including gastrointestinal stromal tumors, systemic mastocytosis and
glioblastoma multiforme. DCC-2618 was specifically designed to improve
the treatment of GIST patients by inhibiting a broad spectrum of
mutations in KIT and PDGFRα. DCC-2618 is a KIT and PDGFRα inhibitor that
blocks initiating KIT mutations in exons 9, 11, 13, 14, 17, and 18,
involved in GIST as well as the primary D816V exon 17 mutation involved
in SM. DCC-2618 also inhibits primary PDGFRα mutations in exons 12, 14,
and 18, including the exon 18 D842V mutation, involved in a subset of
GIST.

About Deciphera Pharmaceuticals

Deciphera Pharmaceuticals 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 the
potential for DCC-2618 to treat GIST; statements regarding the potential
benefits to patients of DCC-2618; statements regarding plans and
timelines for the clinical development of DCC-2618; and Deciphera
Pharmaceuticals’ strategy, business plans and focus. 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,
statements regarding the potential for DCC-2618 to treat GIST;
statements regarding the potential benefits to patients of DCC-2618;
statements regarding plans and timelines for the clinical development of
DCC-2618; and Deciphera Pharmaceuticals’ strategy, business plans and
focus. These and other risks and uncertainties are described in greater
detail in the section entitled “Risk Factors” in Deciphera
Pharmaceuticals’ most recent annual report on Form 10-K, and other
filings that Deciphera Pharmaceuticals may make with the SEC in the
future. Any forward-looking statements contained in this press release
represent Deciphera Pharmaceuticals’ views only as of the date hereof
and should not be relied upon as representing its views as of any
subsequent date. Deciphera Pharmaceuticals explicitly disclaims any
obligation to update any forward-looking statements.

Contacts

Media:
The Yates Network
Gina Nugent, 617-460-3579
gina@theyatesnetwork.com
or
Investor
Relations:
Argot Partners
Laura Perry or Sam Martin,
212-600-1902
Laura@argotpartners.com or Sam@argotpartners.com
or
Company:
Deciphera
Pharmaceuticals, Inc.
Christopher J. Morl, 781-209-6418
Chief
Business Officer
cmorl@deciphera.com