— ICOS Agonist Antibody Well Tolerated Alone and as Combination Immunotherapy —  

— Phase 2 Monotherapy Cohorts Are Currently Enrolling Using ICOS Biomarker Patient Enrichment —

CAMBRIDGE, MA, USA I June 05, 2017 I Jounce Therapeutics, Inc. (NASDAQ:JNCE), a clinical-stage company focused on the discovery and development of novel cancer immunotherapies and predictive biomarkers for patient enrichment, today announced that Phase 1 data from the Company’s ICONIC study of JTX-2011 were presented in a poster (Abstract #192770) at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting. JTX-2011 is a monoclonal antibody targeting ICOS, a protein found on the surface of certain T cells within many solid tumors. The preliminary data show JTX-2011 to be well-tolerated in doses up to 0.3 mg/kg as a monotherapy and in combination with nivolumab in patients with advanced solid tumors.

“We are very encouraged by the safety and pharmacodynamic data from the ICONIC study, which showed JTX-2011 to be well-tolerated as a monotherapy and in combination with nivolumab,” said Beth Trehu, M.D., FACP, chief medical officer of Jounce Therapeutics. “The JTX-2011 Phase 1 data in this poster is the first clinical data to be presented with an ICOS agonist antibody, and includes the safety, PK and PD data, as well as the selected dose for the Phase 2 monotherapy portion of the trial that was initiated in April of this year.”

The Phase 1 portion of the Phase 1/2 ICONIC (ICOS AgONist Antibody for Immunotherapy in Cancer Patients) study was a dose-escalation study to assess safety and tolerability of JTX-2011 and to determine the recommended Phase 2 dose (RP2D) of JTX-2011 as a monotherapy and in combination with nivolumab. The study enrolled patients with any advanced solid tumor who had disease progression after treatment with all available therapies known to confer clinical benefit. Unlike the ongoing Phase 2 study, the Phase 1 study did not include enrichment for patients with the ICOS biomarker.

A summary of results as of May 12, 2017, is as follows:

  • Forty-six subjects were dosed in six cohorts of escalating doses of JTX-2011 alone every three weeks and four cohorts of escalating doses of JTX-2011 plus nivolumab 240 mg IV every three weeks
     
  • Most adverse events were Grade 1 or 2, with the most common being chills, decreased appetite, nausea and fever
     
  • Infusion-related adverse events were reported in 10 participants at doses 0.003 mg/kg through 0.3 mg/kg in both monotherapy and combination
     
  • Immune related adverse events not associated with drug infusion were reported in six participants at doses at or above 0.03 mg/kg, including two dose-limiting toxicities at 1 mg/kg, resulting in a maximum tolerated dose for JTX-2011 monotherapy of 0.3 mg/kg
     
  • 0.3 mg/kg was selected as the recommended Phase 2 dose for JTX-2011 monotherapy based on safety and tolerability, target engagement, PK and peripheral blood immunophenotyping
     
  • Nine out of 12 monotherapy participants at the RP2D and 10 out of 12 combination therapy participants at all dose levels remain on study with limited duration of follow-up

“These early data are promising and support our advancement to the Phase 2 portion of the ICONIC study. As we shift our focus to look at measures of preliminary efficacy, we will be utilizing the biomarker enrichment strategy that defines Jounce’s translational approach, and enroll a certain number of patients with a high percentage of ICOS-expressing immune cells in their tumors into the Phase 2 cohorts. We look forward to gaining important insights on how JTX-2011 may benefit patients that have not had success with currently available therapies,” said Richard  Murray, Ph.D., chief executive officer of Jounce Therapeutics.

Phase 2 Portion of ICONIC Study:

In April 2017, Jounce announced the initiation of the Phase 2 portion of the ICONIC trial, which consists of two parts evaluating preliminary efficacy. Patient enrollment is ongoing in the monotherapy (Part C) portion of the study. The Phase 2 study evaluates JTX-2011 as a monotherapy across more than three disease-specific expansion cohorts in solid tumors, including patients with head and neck squamous cell cancer (HNSCC) and non-small cell lung cancer (NSCLC) and in combination with nivolumab and in over five cohorts, including HNSCC, NSCLC, triple negative breast cancer, melanoma and gastric cancer. Each of these indications was identified by Jounce’s Translational Science Platform as having tumors displaying high percentages of ICOS-expressing infiltrating immune cells, the target of JTX-2011. In addition, individual patients will be stratified for the ICOS biomarker, which measures the percentage of ICOS-expressing immune cells in their tumors, to ensure that sufficient numbers of patients with high ICOS expression, who may be more likely to respond, are enriched into each cohort. 

About the ICONIC Study
The ICONIC study (ICOS AgONist Antibody for Immunotherapy in Cancer Patients) is an open label, dose-escalation and expansion clinical study of JTX-2011 alone or in combination with a fixed dose of nivolumab in subjects with advanced solid tumors . The four-part, adaptive design includes Parts A, B, C and D. Parts A and B comprise the Phase 1 portion of the study and are designed to provide safety, PK and PD data in both the monotherapy (Part A) and combination therapy (Part B) settings. Parts C (monotherapy) and D (combination therapy) are designed to provide preliminary efficacy proof-of-concept data. For more information on the ICONIC trial, visit clinicaltrials.gov.

About JTX-2011
Jounce’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.  Preclinical data support that JTX-2011 may have a dual mechanism of action that stimulates anti-tumor T effector cells, and also reduces the immunosuppressive T regulatory cells in the tumor microenvironment. The company is developing JTX-2011 to treat solid tumors as a single agent and in combination with other therapies.

About Jounce Therapeutics
Jounce 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 tumors to prioritize targets, and then identifies related biomarkers designed to match the right therapy to the right patient. Jounce’s lead product candidate, JTX-2011, is a monoclonal antibody that binds to and activates ICOS and is currently in a Phase 1/2 trial. For more information, please visit http://jouncetx.com/.

SOURCE: Jounce Therapeutics