JNCE Jounce Therapeutics Inc

ICONIC Clinical Data Demonstrates Improved PFS/OS in Patients with Emergence of JTX-2011 Mechanistic Biomarker (ICOS high CD4 T cells)

Jounce Therapeutics, Inc. (NASDAQ: JNCE), a clinical-stage company focused on the discovery and development of novel cancer immunotherapies and predictive biomarkers, today announced that data from its Phase 1/2 ICONIC trial, an open label trial evaluating JTX-2011 monotherapy and in combination with nivolumab, will be the subject of two poster presentations at the upcoming 2019 American Association for Cancer Research (AACR) Annual Meeting at the Georgia World Congress Center in Atlanta, GA on March 31- April 3, 2019. In addition, Jounce Therapeutics will present a poster that will describe the preclinical evaluation of JTX-8064, a highly specific monoclonal antibody that aims to reprogram human macrophages from an immune suppressive to immune active state by inhibiting the cell surface receptor LILRB2.

“The JTX-2011 clinical data being presented show that ICONIC patients with emergence of ICOS hi CD4 T cells in the peripheral blood have improved progression free and overall survival. This finding further validates the role of this ICOS pharmacodynamic biomarker in directing the next stage of the clinical development strategy for JTX-2011. Establishing the importance of this biomarker and its association with improved survival leads us to two distinct paths; first, combination with other agents that are known to induce ICOS hi CD4 T cells which JTX-2011 may then further stimulate; and second, using candidate predictive biomarkers identified through analysis of baseline samples of patients with and without emergence of these cells,” said Elizabeth Trehu, M.D., chief medical officer of Jounce Therapeutics. “In addition to the data from our JTX-2011 program, we will also highlight JTX-8064 and the preclinical evaluation of this novel product candidate and its role in reprogramming tumor-associated macrophages within the tumor microenvironment.”

JTX-2011 Posters Details:Improved progression-free and overall survival (PFS/OS) in patients (pts) with emergence of JTX-2011 associated biomarker (ICOS high CD4 T cells) on the ICONIC trialSession Title: Phase II-III Clinical Trials: Part 2 Location: Exhibit Hall B, Poster Section 16Date and Time: Tuesday April 2, 2019 1:00 PM - 5:00 PM ETPoster Board Number: 3; Permanent Abstract Number: CT189

Genetic and molecular profiling of ICOS hi CD4 T cells demonstrates clonal expansion of TH1 effector cells following JTX-2011 treatment in subjects with solid tumorsSession Title: Biomarkers and Immune Monitoring Location: Exhibit Hall B, Poster Section 22Date and Time: Tuesday April 2, 2019 1:00 PM - 5:00 PM ETPoster Board Number: 16; Permanent Abstract Number: 4053

JTX-8064 Poster Details:Preclinical evaluation of JTX-8064, an anti-LILRB2 antagonist antibody, for reprogramming tumor-associated macrophagesSession Title: Tumor Immune MicroenvironmentLocation: Exhibit Hall B, Poster Section 25Date and Time: Wednesday April 3, 2019 8:00 AM - 12:00 PM ETPoster Board Number: 1; Permanent Abstract Number: 5007

The posters will be available at the start of each session on the “Our Approach” section of the Jounce Therapeutics website at www.jouncetx.com.

Jounce Therapeutics to Host Event and WebcastJounce Therapeutics will host an investor and analyst event beginning at 6:30 p.m. ET and live webcast beginning at 7:00 p.m. ET, on Tuesday, April 2, 2019. To access the live webcast, please visit the “Events & Presentations” page in the Investors and Media section of the company’s website at www.jouncetx.com. The webcast will be archived and made available for replay on the company’s website approximately two hours after the call and will be available for 30 days thereafter.

About JTX-2011Jounce’s lead product candidate, JTX-2011, is a monoclonal antibody that binds to and activates ICOS, a protein on the surface of certain T cells. The company is developing JTX-2011 to treat solid tumors as a single agent and in combination with other therapies.

About JTX-8064JTX-8064 is an anti-Leukocyte Immunoglobulin Like Receptor B2 (LILRB2) antibody and is the first candidate to emerge from Jounce’s Translational Science Platform efforts that focuses on tumor-associated macrophages. JTX-8064 is currently in IND-enabling activities and Jounce anticipates filing an IND and initiating a Phase 1 clinical trial for JTX-8064 in 2019.

About Jounce TherapeuticsJounce Therapeutics, Inc. is a clinical-stage immunotherapy company dedicated to transforming the treatment of cancer by developing therapies that enable the immune system to attack tumors and provide long lasting benefits to patients. Through the use of its Translational Science Platform, Jounce first focuses on specific cell types within the human tumor microenvironment to prioritize targets, and then identifies related biomarkers designed to match the right immunotherapy to the right patient. Jounce has three development-stage programs: its two clinical product candidates, JTX-2011, a monoclonal antibody that binds to and activates ICOS, and JTX-4014, a monoclonal antibody that binds to PD-1 and for potential use in combination with Jounce’s pipeline of future product candidates, and JTX-8064, a monoclonal antibody that binds to LILRB2 that is currently in the IND-enabling phase. For more information, please visit www.jouncetx.com.

Forward-Looking StatementsStatements in this release concerning Jounce’s future expectations and plans, including without limitation, Jounce’s expectations regarding the timing, progress and results of the clinical development of JTX-2011 and JTX-8064, and Jounce’s clinical development strategy may constitute forward looking statements for the purposes of the safe harbor provisions under The Private Securities Litigation Reform Act of 1995 and other federal securities laws and are subject to substantial risks, uncertainties and assumptions. You should not place reliance on these forward looking statements, which include words such as “aims,” “anticipates,” “intend,” “may,” “potential” or similar terms, variations of such terms or the negative of those terms. Although the Company believes that the expectations reflected in the forward-looking statements are reasonable, the Company cannot guarantee such outcomes. Actual results may differ materially from those indicated by these forward-looking statements as a result of various important factors, as well as those risks more fully discussed in the section entitled “Risk Factors” in Jounce’s most recent annual report on Form 10-K or quarterly report on Form 10-Q, as well as discussions of potential risks, uncertainties, and other important factors in Jounce’s subsequent filings with the U.S. Securities and Exchange Commission. All such statements speak only as of the date made, and the Company undertakes no obligation to update or revise publicly any forward-looking statements, whether as a result of new information, future events or otherwise.

Investor Contact: Komal Joshi Jounce Therapeutics, Inc. (857) 320-2523 kjoshi@jouncetx.com

Media Contact: Gina Nugent The Yates Network (617) 460-3579 gina@theyatesnetwork.com