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, 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 masofaniten plus enzalutamide combination dose expansion study ongoing
Cash runway sufficient to fund operations beyond 2025
SOUTH SAN FRANCISCO, California and VANCOUVER, Canada, Feb. 13, 2024 /PRNewswire/ – 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 first quarter ended December 31, 2023.
“As we enter 2024, we are focused on advancing the investigation of masofaniten in combination with second-generation antiandrogen agents, with the goal of improving clinical outcomes for patients battling prostate cancer,” said David Parkinson, MD, President and CEO of ESSA. “We are extremely pleased with the data reported to date from the Phase 1 dose escalation study evaluating masofaniten combined with enzalutamide in patients with mCRPC naïve to second generation anti-androgens where we continue to observe compelling, deep and durable reductions in prostate-specific antigen (“PSA”), along with an encouraging 16.6 month median time to PSA progression. We look forward to reporting updated Phase 1 dose escalation data during 2024. In addition, we continue to advance enrollment in both Phase 1 arms evaluating masofaniten in combination with apalutamide or abiraterone acetate, respectively, and look forward to reporting preliminary data during the second half of 2024.”
“On the financial front, we are bolstered by our strong cash position that we expect will provide sufficient runway to fund our planned operations through several data readouts and beyond 2025. We are excited to execute on our key 2024 objectives which we believe will meaningfully advance the investigation of masofaniten and look forward to providing updates on our progress throughout the year,” concluded Dr. Parkinson.
First Quarter Fiscal 2024 and Recent Highlights
Masofaniten Combination Studies
Reported Phase 1 dose escalation data at multiple medical meetings from the four cohorts of its ongoing Phase 1/2 study evaluating masofaniten in combination with enzalutamide in patients with metastatic castration-resistant prostate cancer (“mCRPC”) naïve to second-generation antiandrogens but may have been treated with chemotherapy in the metastatic castration-sensitive setting. These data were presented at the 2024 ASCO Genitourinary Cancers Symposium, the 2023 Prostate Cancer Foundation Scientific Retreat and at the European Society for Medical Oncology 2023 Congress. As of the most recent data presentation, the results demonstrated that the combination continues to be well tolerated at the dose levels tested through up to 25 cycles of dosing in some patients. Deep and durable 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 are still maturing with a current median follow up of 11.1 months, the median time to PSA progression is 16.6 months. ESSA expects to report updated data from the Phase 1 dose escalation study during the second half of 2024.
Enrollment is underway in the Phase 2 portion of the Phase 1/2 study evaluating the combination of masofaniten and enzalutamide compared to enzalutamide monotherapy in patients with mCRPC naïve to second-generation antiandrogens but who may have been treated with chemotherapy in the metastatic castration-sensitive setting. The Phase 2 portion of the study is an open-label randomized study 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 sites is in progress. ESSA plans to provide guidance for timing of the public disclosure of initial data once the Phase 2 portion has been underway for several months.
Initiated two additional masofaniten combination arms as part of the ongoing Phase 1 masofaniten study. One arm will evaluate masofaniten in combination with abiraterone acetate and prednisone in patients with either metastatic castration-sensitive prostate cancer or mCRPC while the second arm will evaluate masofaniten in combination with apalutamide in patients with non-metastatic castration-resistant prostate cancer after 12 weeks of masofaniten single agent. ESSA expects to report preliminary data from these Phase 1 arms during the second half of 2024.
An investigator-sponsored neoadjuvant study was also initiated evaluating neoadjuvant use of the combination of masofaniten and darolutamide compared to darolutamide monotherapy in high-risk patients undergoing prostatectomy.
Masofaniten Monotherapy Study
On track to complete the Phase 1b masofaniten monotherapy study evaluating masofaniten in patients with late-line mCRPC, which is currently ongoing. The initial results from the study were reported at the 2023 American Society of Clinical Oncology Genitourinary Cancers Symposium, which 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 2024 at a medical conference.
Summary Financial results
(Amounts expressed in U.S. dollars)
Net Loss. ESSA recorded a net loss of $6.0 million for the first quarter ended December 31, 2023 compared to $6.7 million for the first quarter ended December 31, 2022. The decrease in the first quarter was primarily attributed to an increase in investment income over the prior period of $0.5 million.
Research and Development (“R&D”) expenditures. R&D expenditures for the first quarter ended December 31, 2023 were $5.4 million compared to $5.3 million for the first quarter ended December 31, 2022, and include non-cash costs related to share-based payments $526,241 for the first quarter ended 2023 compared to $791,192 for …