Jounce Therapeutics Presents Preclinical Data from JTX-8064/LILRB2 Program at the 2021 American Association for Cancer Research (AACR) Virtual Annual Meeting

-Translational analysis of patients that do not respond to PD-(L)1 inhibitors show high pretreatment intratumoral LILRB2 expression relative to an IFNγ gene signature-

- JTX-8064’s mechanism of action to reprogram macrophages can bridge innate immune cell activity to T cell adaptive immunity in preclinical models-

CAMBRIDGE, Mass., April 10, 2021 (GLOBE NEWSWIRE) -- Jounce Therapeutics, Inc. (NASDAQ: JNCE), a clinical-stage company focused on the discovery and development of novel cancer immunotherapies and predictive biomarkers, today reported new preclinical data on JTX-8064, the first tumor-associated macrophage program from their Translational Science Platform, at the 2021 American Association for Cancer Research (AACR) Virtual Annual Meeting being held April 10-15, 2021. The poster presentation includes data showing a high Leukocyte Immunoglobulin Like Receptor B2 (LILRB2) to interferon gamma (IFNγ) ratio is associated with resistance to PD-(L)1 inhibitor treatment in humans, JTX-8064’s ability to bridge innate and adaptive immunity, and how Jounce’s Translational Science Platform informed indication selection for the Phase 1 INNATE trial.

“The translational analyses presented at AACR link JTX-8064’s mechanism to tumor types that may respond better to LILRB2 inhibition,” said Elizabeth Trehu, M.D., chief medical officer of Jounce Therapeutics. “The Phase 1 INNATE trial is designed to move as quickly as possible to proof of concept and this new data enabled the prioritization of tumor-specific expansion cohorts, which are on track to start enrolling in the second half of 2021. Furthermore, the negative prognostic implications of a high LILRB2 to IFNγ ratio support the role of LILRB2 in resistance to PD-(L)1 inhibitors and highlight the potential for JTX-8064 to reverse this resistance.”

In a poster titled “Tumor associated macrophages and resistance to immune checkpoint blockade: Consideration of cancer indications for the clinical development of JTX-8064, an anti-LILRB2/ILT4 monoclonal antibody” Jounce demonstrated:

• JTX-8064 can induce T cell activation in co-culture with macrophages, demonstrating its potential to bridge the gap between innate and adaptive immune responses;
• CD163+ M2 macrophages co-localize with T cells in the tumor microenvironment, and patients with high levels of LILRB2 or a proprietary tumor-associated macrophage (TAM) signature score relative to an IFNγ signature score are less responsive to PD-(L)1 inhibitors, providing evidence that LILRB2+ macrophages may be involved in mechanisms of primary resistance to PD-(L)1 inhibitors; and 
• Expression profiles of LILRB2 mRNA, TAM signatures, and other inflammatory cell signatures were used to identify tumor types that may benefit most from JTX-8064 treatment and used to inform indication selection for expansion cohorts of the Phase 1 INNATE trial.