On October 31, 2022 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, reported that Janssen Research and Development ("Janssen") is suspending enrollment into the Phase 1 clinical study of EPI-7386 with apalutamide or EPI-7386 with abiraterone acetate plus prednisone in metastatic castration-resistant prostate cancer ("mCRPC") patients as a result of operational recruitment challenges (Press release, ESSA, OCT 31, 2022, View Source [SID1234622610]).

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Before suspending enrollment, Janssen treated three mCRPC patients (pre-chemotherapy) with the combination of EPI-7386 and apalutamide or abiraterone acetate plus prednisone for up to four months of therapy. In all three patients, the combination of both investigational drug products was safe and well tolerated, and yielded sufficient exposures of each investigational drug product, indicative of pharmacological activity. Initial clinical activity was observed in some patients, with two of the three patients achieving a prostate-specific antigen ("PSA") reduction of 90% ("PSA90") within 12 weeks.

"While we are disappointed that Janssen will not be completing this study, we thank Janssen for the conduct of the study to date and the patients who participated in the study. We are encouraged by the favorable safety, pharmacokinetic, and initial clinical activity in these patients as these data further support the data generated in the EPI-7386 combination study with enzalutamide that ESSA is conducting. We are in discussions with Janssen to supply abiraterone acetate and apalutamide for an ESSA-sponsored combination study and expect to provide more details in the coming months," said David Parkinson, Chief Executive Officer of ESSA.

About EPI-7386
EPI-7386 is an investigational, highly-selective, oral, small molecule inhibitor of the N-terminal domain of the androgen receptor. EPI-7386 is currently being studied in a Phase 1 clinical trial (NCT04421222) in men with castration-resistant prostate cancer ("CRPC") whose tumors have progressed on standard-of-care therapies. The U.S. FDA has granted Fast Track designation to EPI-7386 for the treatment of adult male patients with mCRPC resistant to standard-of-care treatment. ESSA is also conducting a Phase 1/2 clinical trial (NCT05075577) of EPI-7386 in combination with enzalutamide in metastatic CRPC patients who have not yet been treated with second-generation antiandrogen therapies. ESSA retains all rights to EPI-7386 worldwide.