NCT06826768

A Ph Ib Study of REGN5678 Plus Cemiplimab in Patients With mCRPC

A Phase Ib Clinical Trial to Optimize Risk Benefit of REGN5678 (PSMAxCD28 Bispecific Antibody) Plus Cemiplimab (Anti-PD-1 Monoclonal Antibody) in Patients With Metastatic Castration-resistant Prostate Cancer

• Status: Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 60 (estimated)
• Sponsor: M.D. Anderson Cancer Center · Academic / Other
• Sex: Male
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

A single-center phase Ib/II dose escalation and dose-expansion clinical trial of REGN5678 plus cemiplimab

Detailed description

Primary Objectives: * To evaluate the safety and tolerability of REGN5678 (PSMAxCD28 bispecific antibody) plus cemiplimab (anti-PD-1) in patients with mCRPC. * To determine the maximum tolerated dose or potential recommended phase II dose (RP2D) of REGN5678 (PSMAxCD28 bispecific antibody) plus cemiplimab (anti-PD-1) in patients with mCRPC Secondary Objectives: * To evaluate efficacy of REGN5678 plus cemiplimab in patients with mCRPC. * To characterize the PK of REGN5678 alone and in combination with cemiplimab * To assess the immunogenicity of REGN5678 and cemiplimab. Exploratory Objective: • To evaluate immune responses in the prostate TME and peripheral blood after treatment with REGN5678 plus cemiplimab as compared to pre-treatment samples.

Conditions

• Prostate Cancer

Interventions

Type	Name	Description
DRUG	REGN5678	Given by IV infusion
DRUG	Cemiplimab	Given by IV infusion

Timeline

• Start date: 2025-07-09
• Primary completion: 2027-05-01
• Completion: 2029-05-01
• First posted: 2025-02-14
• Last updated: 2026-03-04

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study