On May 15, 2020 ESSA Pharma Inc. (Nasdaq: EPIX; TSX-V: EPI), a clinical-stage pharmaceutical company focused on developing novel therapies for the treatment of prostate cancer, reported new preclinical data on ESSA’s clinical candidate, EPI-7386, at the 2020 Virtual American Urological Association ("AUA") Annual Meeting (Press release, ESSA, MAY 15, 2020, View Source [SID1234558189]).

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In an oral poster presentation titled, "The preclinical characterization and development of EPI-7386, an N-terminal domain androgen receptor inhibitor for the treatment of prostate cancer", a more in-depth preclinical characterization of EPI-7386 including gene expression analyses and the toxicologic profile was presented. The studies highlight new information about EPI-7386 including:

In vitro cellular gene expression analyses demonstrate that EPI-7386:
Inhibits androgen-induced genes with major similarities but some differences from enzalutamide in a cellular model sensitive to androgen receptor inhibitors.
In the same cellular model, the combination of enzalutamide and EPI-7386 inhibits androgen-induced gene expression more completely and broadly.
EPI-7386 shows superiority to enzalutamide in inhibiting androgen-induced genes in an androgen receptor resistant model, and in contrast to enzalutamide, also blocks genes induced by the AR-V7 androgen receptor splice variant.
Toxicology studies evaluating the safety profile of EPI-7386 demonstrate that:
Very high plasma exposures of EPI-7386 were achieved across all studies.
The drug was well tolerated at both the low and middle doses, corresponding to drug plasma exposures 2-5 fold higher than the efficacious exposures achieved in mouse xenograft models.
The highest doses tested were characterized as the HNSTD (highest non-severely toxic dose) and only exhibited body weight loss and reduced food consumption. The drug plasma exposures achieved at this high dose were 7-10 fold higher than the efficacious exposures achieved in mouse xenograft models.
The starting clinical dose of EPI-7386 will be 200 mg given once-daily
"The breadth of in vitro and in vivo studies utilized to profile EPI-7386 preclinically demonstrate an encouraging profile for EPI-7386 across a variety of antiandrogen sensitive and antiandrogen-resistant cellular models, xenograft and patient-derived xenograft mouse models, and gene expression analyses. The favorable toxicologic profile of EPI-7386 observed in our IND-enabling studies at very high exposures will permit initiation of the Phase 1 study at a dose of 200 mg per day, which should allow us to reach biologically relevant blood levels of EPI-7386 in patients quickly," said Dr. David R. Parkinson, President & Chief Executive Officer. "We look forward to beginning patient dosing soon in our initial phase 1 study of EPI-7386 in mCRPC patients whose tumors are progressing on current anti-androgens.".