8-K: Olema Pharmaceuticals Announces Positive Interim Results for Palazestrant Combination Therapy in Breast Cancer

Olema Pharmaceuticals reported promising interim results from a Phase 1b/2 clinical study of palazestrant in combination with ribociclib for ER+/HER2metastatic breast cancer, showing a high clinical benefit rate and good tolerability.

Summary

• Olema Pharmaceuticals announced interim results from a Phase 1b/2 clinical study of palazestrant (OP-1250) combined with ribociclib for treating ER+/HER2metastatic breast cancer.
• The study included 50 patients with recurrent, locally advanced or metastatic breast cancer.
• The combination of up to 120 mg of palazestrant with 600 mg of ribociclib was well tolerated, with no new safety concerns.
• Palazestrant did not affect ribociclib drug exposure, and ribociclib had no significant impact on palazestrant exposure.
• A clinical benefit rate (CBR) of 85% was observed across all CBR-eligible patients (11 out of 13).
• The CBR was 83% in ESR1-mutant patients (5 out of 6), 86% in ESR1-wild-type patients (6 out of 7), and 83% in prior CDK4/6 inhibitor patients (10 out of 12).
• Partial responses were seen in five patients out of 23 response-evaluable patients (two confirmed, three unconfirmed).
• The study is now fully enrolled with 60 patients.
• The longest duration on treatment was 44 weeks, and 66% of patients remained on treatment at the data cut-off date of March 13, 2024.
• The company has initiated a Phase 3 trial (OPERA-01) for palazestrant as a monotherapy and is planning a Phase 3 trial for palazestrant in combination with ribociclib.

Sentiment

Score: 8

Explanation: The document presents very positive interim results for a combination therapy with a high clinical benefit rate and good tolerability, suggesting a strong potential for future success. The company also has a solid cash position.

Positives

• The combination therapy demonstrated a high clinical benefit rate of 85% across all eligible patients.
• The treatment was well-tolerated with no new safety signals or increased toxicity.
• Palazestrant showed favorable pharmacokinetics with high oral bioavailability and a half-life of eight days.
• There was no clinically significant drug-drug interaction between palazestrant and ribociclib.
• The study showed anti-tumor activity in both ESR1 wild-type and ESR1 mutant patients.
• A tablet formulation of palazestrant has reduced upper gastrointestinal adverse events compared to the capsule formulation.
• The company has a strong cash position of approximately $249 million as of March 31, 2024.

Negatives

• Ten patients required dose reduction of ribociclib due to adverse events such as QTcF prolongation, neutropenia, or fatigue.
• Two patients discontinued ribociclib due to neutropenia, although they continued on palazestrant.
• Some patients experienced treatment-emergent adverse events, although most were Grade 1 or 2.

Risks

• The study results are interim and based on a limited number of patients.
• The forward-looking statements are subject to various risks and uncertainties, and actual results could differ materially.
• The development of palazestrant is subject to regulatory approvals and clinical trial outcomes.
• There are risks inherent in conducting cross-trial comparisons, and the results should be interpreted with caution.

Future Outlook

Olema plans to continue clinical development of palazestrant, including a Phase 3 monotherapy trial (OPERA-01) and a planned Phase 3 trial in combination with ribociclib, with the goal of transforming the endocrine therapy standard of care for breast cancer.

Management Comments

• Sean P. Bohen, M.D., Ph.D., President and Chief Executive Officer of Olema Oncology, stated that the data presented at the ESMO Breast Cancer Annual Congress further supports the potential of palazestrant as a backbone endocrine therapy.
• Management is excited with the progress and looks forward to advancing towards their goal of transforming the endocrine therapy standard of care for breast cancer.

Industry Context

The announcement is significant as it presents promising data for a novel endocrine therapy in combination with a CDK4/6 inhibitor, addressing a critical need in the treatment of ER+/HER2metastatic breast cancer. The results position palazestrant as a potential competitor to existing therapies and a possible new standard of care.

Comparison to Industry Standards

• The clinical benefit rate of 85% for the palazestrant-ribociclib combination is competitive with other treatments in this space.
• The MAINTAIN study of ribociclib after CDK4/6i progression serves as a clinical benchmark, and the palazestrant combination shows early signals of efficacy in a similar patient population.
• Ribociclib has demonstrated overall survival benefit in combination with endocrine therapy, which is a key advantage compared to other CDK4/6 inhibitors like palbociclib and abemaciclib.
• The combination of palazestrant with ribociclib is unique as it is the only novel endocrine therapy being combined with ribociclib in a pivotal trial, while other combinations use palbociclib or physician's choice CDK4/6i.

Stakeholder Impact

• Shareholders: The positive results are likely to be viewed favorably, potentially increasing the company's stock value.
• Patients: The study offers hope for a new and effective treatment option for ER+/HER2metastatic breast cancer.
• Employees: The positive results may boost morale and job security.
• Medical Community: The data provides valuable insights into the potential of palazestrant in combination therapy.

Next Steps

• Continue clinical development of palazestrant.
• Advance the Phase 3 monotherapy trial (OPERA-01).
• Plan a Phase 3 trial for palazestrant in combination with ribociclib.
• Present further data at future medical conferences.

Key Dates

Keywords

palazestrant, ribociclib, breast cancer, ER+/HER2-, metastatic, clinical trial, oncology, endocrine therapy, ESR1, CDK4/6 inhibitor