SOUTH SAN FRANCISCO - 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 announced the presentation of updated dose escalation data from its Phase 1/2 study evaluating masofaniten in combination with enzalutamide at the 30th Annual Prostate Cancer Foundation Scientific Retreat, taking place October 26-28, 2023, in Carlsbad, CA.

Masofaniten is a first-in-class N-terminal domain androgen receptor ('AR') inhibitor that suppresses androgen activity through a novel mechanism of action and is being developed for the treatment of prostate cancer. The poster presentation is available on the 'Publications' section of the Company's website at www.essapharma.com.

'This poster, presented today at the Prostate Cancer Foundation Scientific Retreat, contains updated cohort 4 data from the dose escalation portion of our Phase 1/2 study evaluating the combination of masofaniten and enzalutamide in patients with metastatic castration-resistant prostate cancer ('mCRPC'),' said David Parkinson, MD, President and CEO of ESSA. 'While the data for patients in cohort four are still maturing, these updated data continue to demonstrate that the combination is well tolerated and leads to deep and durable reductions in prostate-specific antigen ('PSA'), including in cohort 4, which reflects the dosing regimen that is being evaluated in the Phase 2 dose expansion. We look forward to providing future updates.'

Poster presentation details

Title: Phase 1/2 Trial of Oral EPI-7386 (masofaniten) in Combination with Enzalutamide (Enz) Compared with Enz Alone in Subjects with Metastatic Castration-Resistant Prostate Cancer (mCRPC): Current Phase 1 (P1) results

Presenting Author: Andrew Laccetti, MD, MS, Memorial Sloan Kettering Cancer Center

Date and time: Thursday, October 26, 2023; 7:30-10:30 p.m. PT

Data summary: This Phase 1/2 multicenter, open-label clinical trial is enrolling patients with mCRPC who have received androgen deprivation therapy and who are naive to second-generation antiandrogens but may have been treated previously with one line of prior chemotherapy in the metastatic hormone-sensitive prostate cancer setting. The data presented today are from the first four cohorts of patients in the Phase 1 dose escalation portion of the study. Masofaniten has no effect on enzalutamide exposure, thus allowing the use of full dose per label (160mg) of enzalutamide in combination. Enzalutamide reduces masofaniten exposure but twice daily dosing of masofaniten appears to mitigate the reduction and maintains clinically relevant drug exposures.

In patients evaluable for safety (n=18), masofaniten combined with enzalutamide, continues to be well-tolerated at the doses tested through 21 cycles of dosing in some patients. Most frequent adverse events were Grade 1 and 2, related to either AR inhibition or gastrointestinal tract irritation. In Cohort 4, one patient experienced a Grade 3 rash, which was observed immediately following administration of masofaniten combined with enzalutamide and deemed probably related.

In the patients evaluable for efficacy (n=16), rapid, deep and durable reductions in PSA were observed, regardless of previous chemotherapy status, including in patients who received lower than the full dose of enzalutamide (120 mg). In the first three cohorts, 90% of patients (9 of 10) achieved PSA50 and PSA90, 80% of patients (8 of 10) achieved PSA90 in less than 90 days, and 70% of patients (7 of 10) achieved PSA

(C) 2023 Electronic News Publishing, source ENP Newswire