Olema Oncology Announces New Data from the Phase 1b/2 Trial of Palazestrant Plus Ribociclib in ER+/HER2- Metastatic Breast Cancer at ESMO 2025

• Palazestrant in combination with ribociclib demonstrated encouraging activity across all dose cohorts and subgroups
• Median PFS was 15.5 months in the 120 mg palazestrant cohort across all patients
• In the 120 mg palazestrant cohort among patients with prior CDK4/6i treatment, median PFS was 9.2 months in patients with ESR1 wild-type tumors and 13.8 months in patients with ESR1 mutant tumors
• Combination continues to demonstrate favorable tolerability and a safety profile consistent with the known profiles of each drug
• Data support the ongoing Phase 3 OPERA-02 trial of palazestrant in combination with ribociclib in frontline advanced or metastatic breast cancer
  
  

SAN FRANCISCO, Oct. 18, 2025 (GLOBE NEWSWIRE) -- Olema Pharmaceuticals, Inc. (“Olema” or “Olema Oncology”, Nasdaq: OLMA), a clinical-stage biopharmaceutical company focused on the discovery, development, and commercialization of targeted therapies for breast cancer and beyond, today announced updated data from the Phase 1b/2 study of palazestrant in combination with ribociclib in patients with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) advanced or metastatic breast cancer. These findings will be presented in a poster session on October 20 at the European Society for Medical Oncology (ESMO) Congress 2025 in Berlin, Germany.

“We are very pleased with these latest data showing compelling progression-free survival and favorable tolerability of palazestrant plus ribociclib, further reinforcing this regimen’s potential as a new standard of care in metastatic breast cancer,” said Sean P. Bohen, M.D., Ph.D., President and Chief Executive Officer of Olema Oncology. “These data showcase the activity of the combination in both ESR1 mutant and wild-type tumors, an important component for effective frontline treatment, and underscore the importance of complete ER antagonism in the treatment of ER-positive breast cancer. As we work to transform the breast cancer treatment paradigm, we are increasingly confident in palazestrant’s potential to become a best-in-class, backbone endocrine therapy and are excited to now have our second Phase 3 trial, OPERA-02, underway evaluating palazestrant with ribociclib in the frontline setting.”