A Trial of BXCL701 and Pembrolizumab in Patients With mCRPC Either Small Cell Neuroendocrine Prostate Cancer or Adenocarcinoma Phenotype.

Summary

An open-label, multicenter, Phase 1b/2 study to identify the recommended Phase 2 dose and assess the efficacy and safety of BXCL701 administered orally, as monotherapy and in combination with PEMBRO, in patients with mCRPC. Patients enrolled in the Phase 2a portion of the study will have either Small Cell Neuroendocrine Prostate Cancer(SCNC)(Cohort A) or adenocarcinoma phenotype (Cohort B), while the Phase 2b randomized portion of the study will enroll only the histologic subtype(s) showing preliminary evidence in Phase 2a. The study will also assess other efficacy parameters, such as rPFS, PSA PFS, OS, and DOR, as well as the safety of the combined treatment. The study will consist of three components.

Timeline

Start

2019-02-12

Primary completion

2023-10-31

Completion

2025-08-31

Outcome

Met primary endpoint

release “BXCL701 plus KEYTRUDA® (pembrolizumab) demonstrated composite response rate of 25% in patients with metastatic SCNC-variant castration-resistant prostate cancer” bioxceltherapeutics.com ↗

release “In the evaluable patient cohort (n = 28), 7 (25%) patients achieved a composite response, the primary endpoint of the trial.” bioxceltherapeutics.com ↗

Publications

• Aggarwal R, Zhang J, Monk P, Zhu X, Jones R, Linch M, Costin D, de Bono J, Karsh LI, Petrylak DP, Zhang L, Deshpande R, Borderies P, Huang J, O'Neill V, Donkor M, Tagawa S. Phase 2 study of talabostat, a small molecule inhibitor of dipeptidyl peptidases (DPP), administered in combination with pembrolizumab in patients with small cell neuroendocrine prostate cancer. J Immunother Cancer. 2026 May 11;14(5):e014242. doi: 10.1136/jitc-2025-014242.

Drugs

Evaluation	Drug	Modality	Dose	Route
Subject	BXCL701 monotherapy	Small molecule	0.4 mg	Oral
Subject	BXCL701 monotherapy	Small molecule	0.6 mg	Oral
Subject	Pembrolizumab	Monoclonal antibody	200 mg	Intravenous

Indications