Masofaniten Phase 1 Data Presented at 2024 ASCO GU Cancers Symposium

ESSA Pharma is advancing its Phase 1/2 clinical trial of masofaniten, an innovative N-terminal domain androgen receptor inhibitor, in combination with enzalutamide for prostate cancer treatment. The trial's data, presented at the 2024 ASCO Genitourinary Cancers Symposium, indicate that the drug combination is well-tolerated and has led to significant reductions in prostate-specific antigen (PSA) levels among patients with metastatic castration-resistant prostate cancer (mCRPC). Notably, 81% of the patients achieved a PSA90 response, with 69% reaching this milestone within 90 days, and 63% achieving a PSA level below 0.2ng/mL. The median time to PSA progression stands at 16.6 months, suggesting a promising durability of response.

The study, which is still enrolling participants across multiple centers in the USA, Canada, and Australia, with plans to expand to Europe, has not reached its maximum tolerated dose, indicating the safety of the treatment. The recommended Phase 2 combination doses are masofaniten 600 mg twice daily and enzalutamide 160 mg once daily. Masofaniten's unique mechanism targets a part of the androgen receptor not addressed by current therapies, potentially offering a new option for mCRPC patients who have not responded to second-generation antiandrogens.

The Phase 2 dose expansion aims to compare the efficacy of the combination therapy to enzalutamide alone, further investigating the benefits of masofaniten for mCRPC patients. The U.S. Food and Drug Administration has recognized masofaniten's potential by granting it Fast Track designation for the treatment of mCRPC patients resistant to standard care. ESSA Pharma retains global rights to masofaniten and is committed to exploring its long-term benefits for prostate cancer patients.