On April 17, 2026 ORIC Pharmaceuticals, Inc. (Nasdaq: ORIC), a clinical stage oncology company focused on developing treatments that address mechanisms of therapeutic resistance, reported the presentation of multiple poster presentations at the 2026 American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting highlighting the potential of rinzimetostat (ORIC-944), a potent and selective allosteric inhibitor of PRC2 to treat prostate cancer. The posters can be found in the publication section of ORIC’s website here.
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"Our research continues to show the therapeutic potential of PRC2 inhibition across the prostate cancer disease spectrum, by reducing tumor adaptability and sustaining the benefit derived from androgen-receptor targeted therapies," said Lori Friedman, PhD, chief scientific officer. "Additionally, our preclinical studies reveal that targeting PRC2 via EED has potential advantages over targeting EZH2, which, together with the clinical data generated to date, furthers our conviction that rinzimetostat is a potential best-in-class PRC2 inhibitor."
Poster presentations:
Rinzimetostat blockade of PRC2 activity, a key mechanism of treatment resistance, improves response of androgen receptor pathway inhibition across a spectrum of prostate cancer models
Key findings of the presentation:
In a transcriptomics analysis of >1,100 prostate samples spanning normal prostate, primary prostate cancer, and metastatic disease, PRC2 activity was observed early in the development of prostate cancer and was sustained during disease progression and treatment resistance, highlighting it as a critical therapeutic target.
More than half of localized primary tumors demonstrated elevated PRC2 activity vs. normal prostate tissue, and an elevated PRC2 activity in locally advanced tumors associates with poor survival, indicative of a key role early in the disease.
Elevated PRC2 activity was observed in the vast majority of both metastatic CSPC and metastatic CRPC tumors relative to normal prostate tissue.
Rinzimetostat in combination with darolutamide demonstrated antitumor activity across a breadth of in vivo models representing the prostate cancer continuum, including CSPC and CRPC.
Rinzimetostat, an allosteric EED inhibitor with best-in-class properties for the treatment of prostate cancer, is effective in PRC2 methyltransferase-resistant settings in preclinical studies
Key findings of the presentation:
PRC2 inhibition induces transcriptional and chromatin effects that restrain tumor plasticity and enhance antitumor activity of androgen receptor inhibitors in prostate cancer models.
Differential potency of PRC2 inhibitors on EZH1- vs. EZH2-containing complexes impacts activity in resistance contexts, providing potential advantages for EED targeting.
Rinzimetostat retained antitumor activity in prostate cancer cells with overexpressed EZH1 in vitro, while potency was diminished for mevrometostat or tazemetostat.
Preclinical studies show that rinzimetostat overcomes acquired resistance mechanisms observed in the clinic for tazemetostat and valemetostat.
Rinzimetostat demonstrates improved solubility, oral bioavailability, CYP profile, and clinical half-life versus comparator compounds.
(Press release, ORIC Pharmaceuticals, APR 17, 2026, View Source [SID1234664473])