Safety and Anti-Tumor Study of Oral EPI-506 for Patients With Metastatic Castration-Resistant Prostate Cancer

Safety and Anti-Tumor Study of Oral EPI-506 for Patients With Metastatic Castration-Resistant Prostate Cancer

A Phase 1/2 Open-Label Study to Assess the Safety, Pharmacokinetics, and Anti-Tumor Activity of Oral EPI-506 in Patients With Metastatic Castration-Resistant Prostate Cancer

The study will consist of 2 parts: Part I (Dose Escalation) and Part II (Dose Expansion). In Part I, patients will participate in single, multiple, and long-term dosing periods using EPI-506 to determine safety, pharmacokinetics, the maximum tolerated dose, and preliminary indications of anti-tumor activity. Part I is an open-label, adaptive 3 + 3 design, dose-escalation study. Approximately six dose levels of EPI-506 will be studied, beginning at 80 mg/day. Enrolled patients may be allowed to escalate to a subsequent dose cohort after their initial twelve weeks. Additional patients may be enrolled at any safe dose level prior to or concurrent with enrolling patients in Part II. In Part II, 3 patient populations; post-abiraterone metastatic castration-resistant prostate cancer (mCRPC) but enzalutamide-naïve, post-enzalutamide mCRPC but abiraterone-naïve, and post-abiraterone and enzalutamide mCRPC will be studied at the recommended Phase 2 dose (RP2D) determined in Part I over 12 weeks of daily dosing. Approximately 120 patients (40 in each cohort) will be enrolled.

Patients will receive EPI-506 as an oral softgel capsule. Part 1: Approximately six dose levels of EPI-506 will be studied, beginning at 80 mg/day. During the Single-Dose Period, patients will first receive a dose of EPI-506 in the fasted state followed by 2 days of washout, and then patients will receive a second dose of EPI-506 in the fed state followed by 2 days of washout. Patients will then enter the Multiple Dosing and Long-term Dosing Period where they will receive once or twice daily dosing in a fed or fasted state until they meet discontinuation criteria. Part 2: The dose in Part 2 will be determined in Part 1 of the study. Patients will receive the Part 2 dose daily until they meet discontinuation criteria.

Part I: Safety and tolerability assessed by vital signs, laboratory measurements, and frequency and severity of treatment-related adverse events

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Assessed by apparent volume of distribution during the terminal phase after extravascular administration (Vz/F)

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, 24h, and 48h after dose; Day 8 at pre-dose, and at 15min, 30min 1h, 2h, 4h, 6h, 8h, 12h, 24h after dose.

Part II: Safety and tolerability assessed by vital signs, laboratory measurements, and frequency and severity of treatment-related adverse events

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Day 8 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, 8h, 12h, and 24h after dose; Week 12 at pre-dose, and at 15min, 30min, 1h, 2h, 4h, 6h, and 8h after dose.

Radiographic progression evaluated per modified Response Evaluation Criteria in Solid Tumors (mRECIST) v1.1

Radiographic progression evaluation per mRECIST v1.1 in patients with measurable soft tissue disease at baseline

Inclusion Criteria: Adenocarcinoma of the Prostate Metastatic Disease with at least one lesion on bone scan and/or soft tissue on CT/MRI Demonstrated progression on abiraterone and/or enzalutamide Demonstrated PSA progression within 12 weeks of study participation Castrate testosterone levels at screening with continued Luteinizing hormone-releasing hormone (LHRH) therapy Eastern Cooperative Oncology Group (ECOG) score between 0-1 Asymptomatic or mildly symptomatic Exclusion Criteria: Candidates for cytotoxic chemotherapy Received more than one line of chemotherapy Received more than one treatment course of enzalutamide or abiraterone Inadequate washout of prohibited hormonally active agents or other prior treatments for prostate cancer (PCa) Known intra-cerebral disease or brain mets Spinal cord compression within 6 months Prior treatment with investigative androgen receptor (AR) agents