Oncternal Therapeutics Announces First Patient Dosed in Phase 1/2 Study of Dual-Action AR Inhibitor, ONCT-534, in Patients with Metastatic Castration-Resistant Prostate Cancer

SAN DIEGO, Oct. 05, 2023 (GLOBE NEWSWIRE) -- Oncternal Therapeutics, Inc. (Nasdaq: ONCT), a clinical-stage biopharmaceutical company focused on the development of novel oncology therapies, today announced that the first patient has been dosed in the Phase 1/2 dose escalation/dose expansion study of ONCT-534, the company’s dual-action androgen receptor inhibitor.

“The dosing of the first patient with ONCT-534 is an important milestone for patients suffering from advanced prostate cancer who have relapsed or are refractory after treatment with AR signaling inhibitors,” said Salim Yazji, M.D., Oncternal’s Chief Medical Officer. “Preclinical studies suggest that ONCT-534 may address important tumor escape mechanisms that result in resistance to currently available AR inhibitors, such as enzalutamide or abiraterone. We intend to advance the dose escalation portion of the Phase 1/2 Study ONCT-534-101 quickly, and we will be enrolling patients in sites across the U.S. over the coming weeks, and in the United Kingdom in early 2024. We expect to report initial clinical data in the first half of 2024.”

ONCT-534 is a dual-action androgen receptor inhibitor (DAARI) that interacts with both the N-terminal domain and the ligand-binding domain (LBD) of the androgen receptor (AR), inhibiting cell growth and inducing AR degradation. Preclinical studies have shown activity in prostate cancer models against both unmutated AR, and against multiple mutations, including AR amplification, mutations in the AR LBD, and splice variants with loss of the AR LBD.

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 anti-tumor activity of ONCT-534 in patients with metastatic castration-resistant prostate cancer (mCRPC) who have relapsed or are refractory to approved androgen receptor signaling inhibitors (ARSIs) including enzalutamide, abiraterone, apalutamide and darolutamide. After the safety and tolerability of ONCT-534 have been assessed to select the recommended Phase 2 dose (RP2D) in Phase 1, Phase 2 will commence to further validate the dose and evaluate the safety and efficacy of ONCT-534.