Oncternal Therapeutics Enrolls Patients into the Third Dosing Cohort of its Phase 1/2 Study of ONCT-534 for the Treatment of R/R Metastatic Castration-Resistant Prostate Cancer

SAN DIEGO, Jan. 08, 2024 (GLOBE NEWSWIRE) -- Oncternal Therapeutics, Inc. (Nasdaq: ONCT), a clinical-stage biopharmaceutical company focused on the development of novel oncology therapies, today announced that the fourth patient has now been enrolled into its Phase 1/2 study of ONCT-534, its dual-action androgen receptor inhibitor, for the treatment of patients with advanced prostate cancer who are relapsed or refractory to approved androgen receptor pathway inhibitors (ARPI). The last two patients were enrolled into the third dosing cohort, to receive ONCT-534 at a dose of 160 mg taken orally each day. The study utilizes an adaptive Bayesian Optimal Interval (BOIN) design, under which the first two dosing cohorts treated one patient each at 40 mg ONCT-534 per day and 80 mg ONCT-534 per day, respectively. The decision to proceed to dose level 3 was confirmed by the study’s Safety Review Committee (SRC).

“The ONCT-534-101 investigators are enthusiastic about this study, and we are excited about the enrollment and progress through the initial dosing levels. Reaching the third cohort represents an important milestone for the program, as we believe we are nearing potentially therapeutic doses that may benefit prostate cancer patients who have progressed after treatment with approved ARPI such as enzalutamide, abiraterone, apalutamide and darolutamide,” said Salim Yazji M.D., Chief Medical Officer at Oncternal Therapeutics. “We believe ONCT-534, with its novel mechanism of action involving both the ligand-binding domain and the N-terminal domain of the androgen receptor (AR), may address a significant unmet medical need for patients with advanced metastatic prostate cancer, especially those with splice variants of the AR, mutations in the ligand-binding domain of the AR, or AR amplification, common mechanisms of resistance that may develop to treatment with currently approved AR pathway inhibitors.”

About Study ONCT-534-101
Study ONCT-534-101 is a Phase 1/2, single-arm, open-label, multi-center study to evaluate the safety and tolerability, pharmacokinetics, and preliminary anti-tumor activity of ONCT-534 in patients with mCRPC who have relapsed or are refractory to approved ARPIs including enzalutamide, abiraterone, apalutamide and darolutamide. After the safety and tolerability and preliminary antitumor activity of ONCT-534 have been assessed in the Phase 1 portion of this study, Phase 2 will commence to further evaluate the safety and preliminary antitumor activity of ONCT-534 to support selecting an optimal dose.