Combination of masofaniten plus enzalutamide continues to be well tolerated with deep and durable reductions in PSA in Phase 1 dose escalation in patients with mCRPC naïve to second generation antiandrogens, including 81% of patients achieving PSA90, 69% of patients achieving PSA90 in less than 90 days, and 63% of patients achieving PSA <0.2ng/mL Phase 2 dose expansion underway evaluating masofaniten plus enzalutamide in patients with mCRPC naïve to second generation antiandrogens; ESSA projecting completion of enrollment in 1Q25, with preliminary data expected in mid-2025 Cash runway sufficient to fund operations beyond 2025 SOUTH SAN FRANCISCO, Calif. and VANCOUVER, Canada, May 14, 2024 /CNW/ - ESSA Pharma Inc. ("ESSA", or the "Company") (NASDAQ:EPIX), a clinical-stage pharmaceutical company focused on developing novel therapies for the treatment of prostate cancer, today provided a corporate update and reported financial results for the fiscal second quarter ended March 31, 2024. "The year is off to a strong start with the presentation of updated Phase 1 masofaniten dose escalation data at the 2024 ASCO Genitourinary Cancers Symposium ("ASCO-GU"), which demonstrated that masofaniten combined with enzalutamide continues to be well tolerated with deep and durable reductions in prostate-specific antigen ("PSA") in patients with metastatic castration-resistant prostate cancer ("mCRPC") naïve to second-generation antiandrogens," said David Parkinson, MD, President and CEO of ESSA. "Looking ahead, we have multiple critical milestones we are working toward, including reporting more updated data from the Phase 1 dose escalation study evaluating masofaniten combined with enzalutamide in this patient population during the second half of 2024, and completing enrollment in the Phase 2 dose expansion study evaluating masofaniten in combination with enzalutamide during the first quarter of 2025, with preliminary data expected to follow in mid-2025." Second Quarter Fiscal 2024 and Recent Highlights Masofaniten Combination Studies Reported updated Phase 1 dose escalation data from the ongoing Phase 1/2 study evaluating masofaniten in combination with enzalutamide in patients with mCRPC naïve to second-generation antiandrogens but may have been treated with chemotherapy in the metastatic castration-sensitive setting. The results, which were presented at the ASCO-GU symposium in January 2024, demonstrated that the combination regimen continues to be well tolerated at the dose levels tested in up to 25 cycles of dosing in some patients. Reductions in PSA were observed across evaluable patients for efficacy in all dosing cohorts (n=16). Across all dosing cohorts, 88% of patients achieved PSA50, 81% of patients achieved PSA90, 69% of patients achieved PSA90 in less than 90 days, and 63% of patients achieved PSA <0.2ng/mL. While the data for time to PSA progression were still maturing, the median time to PSA progression was reported as 16.6 months with a median follow up at that time of 11.1 months. ESSA expects to report updated data from the Phase 1 dose escalation study during the second half of 2024. Masofaniten is currently being evaluated in combination with enzalutamide compared to enzalutamide monotherapy in a Phase 2 dose randomized study in patients with mCRPC naïve to second-generation antiandrogens but who may have been treated with chemotherapy in the metastatic castration-sensitive setting. Enrollment in the Phase 2 portion of this Phase 1/2 study is expected to be completed during the first quarter of 2025. This Phase 2 study has an open-label randomized design comparing 160 mg once-daily of single agent enzalutamide to the combination of masofaniten with enzalutamide and is expected to enroll approximately 120 patients. The recommended Phase 2 combination dose was identified as masofaniten 600 mg twice-daily combined with enzalutamide 160 mg once daily. The study is currently enrolling at approximately 25 sites in the USA, Canada, and Australia. Expansion to European clinical sites is in progress with an additional 15 clinical sites planned to be activated by 3Q24. ESSA expects to report preliminary data from the Phase 2 dose expansion portion of the study in mid-2025. Two additional masofaniten combination arms are currently enrolling as part of the ongoing Phase 1 masofaniten study. One arm is evaluating masofaniten in combination with abiraterone acetate and prednisone in patients with either metastatic castration-sensitive prostate cancer or mCRPC, while the second arm is evaluating masofaniten in combination with apalutamide in patients with non-metastatic castration-resistant prostate cancer after 12 weeks of masofaniten single agent. Two additional investigator-sponsored studies testing combinations of masofaniten with darolutamide or enzalutamide in different patient populations are underway: a) an Australian investigator-sponsored neoadjuvant study evaluating neoadjuvant use of the combination of masofaniten and darolutamide compared to darolutamide monotherapy in high-risk patients undergoing prostatectomy and b) an investigator-sponsored study which is testing masofaniten and enzalutamide in metastatic castration-sensitive prostate cancer patients. Masofaniten Monotherapy Study ESSA remains on track to complete the Phase 1b masofaniten monotherapy study evaluating masofaniten in patients with mCRPC resistant to second-generation antiandrogens. The initial results from the monotherapy study were reported at the 2023 ASCO-GU Symposium, and demonstrated that masofaniten monotherapy was well-tolerated, achieved clinically significant exposures, and showed preliminary signals of anti-tumor activity in a subset of patients. ESSA plans to present the complete Phase 1a and 1b monotherapy results in the second half of 2024 at a medical conference. Summary Financial results(Amounts expressed in U.S. dollars) Net Loss. ESSA recorded a net loss of $9.0 million for the second quarter ended March 31, 2024 compared to