RWF_R5678-ONC-1879

A Phase 1/2 Study of REGN5678 (Anti-PSMAxCD28) With Cemiplimab (Anti-PD-1) in Patients With Metastatic Castration-resistant Prostate Cancer

The primary objectives of the study in Dose Escalation are to evaluate safety, tolerability, and pharmacokinetics (PK) of REGN5678 alone and in combination with cemiplimab and in Dose Expansion are to assess efficacy, as measured by objective response rate (ORR) per modified Prostate Cancer Working Group 3 (PCWG3) criteria, of REGN5678 in combination with cemiplimab.
The secondary objectives of the study in Dose Escalation are to assess efficacy, as measured by ORR per modified PCWG3 criteria, of REGN5678 in combination with cemiplimab and in Dose Expansion are to characterize the safety profile in each expansion cohort and to characterize the PK of REGN5678 in combination with cemiplimab. Secondary objectives in both Dose Escalation and Dose Expansion are to assess efficacy of REGN5678 in combination with cemiplimab, as measured by additional criteria and to assess immunogenicity of REGN5678 in combination with cemiplimab.

Inclusion Criteria:
• Histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma
• Metastatic, castration-resistant prostate cancer (mCRPC) that has progressed within 6 months prior to screening
• Has received ≥2 lines of approved systemic therapy for mCRPC, including a second -generation hormonal agent
• Adequate organ and bone marrow function

Exclusion Criteria:
• Has received treatment with an approved systemic therapy within 3 weeks of dosing or has not yet recovered (ie, grade ≤1 or baseline) from any acute toxicities
• Has received any previous systemic biologic therapy within 5 half-lives of first dose of study therapy
• Has received prior PSMA-targeting therapy
• Dose Expansion Only: Has had prior anti-cancer immunotherapy
• Any condition that requires ongoing/continuous corticosteroid therapy (>10 mg prednisone/day or anti-inflammatory equivalent) within 1 week prior to the first dose of study therapy
• Ongoing or recent (within 5 years) evidence of significant autoimmune disease that required treatment with systemic immunosuppressive treatments
• Encephalitis, meningitis, organic brain disease (eg, Parkinson's disease) or uncontrolled seizures in the year prior to first dose of study therapy
• Uncontrolled infection with human immunodeficiency virus (HIV), hepatitis B or hepatitis C infection; or diagnosis of immunodeficiency

NOTE: Other protocol defined Inclusion/Exclusion Criteria apply
Phase I/II
NCT03972657
Oncology
Genitourinary
Brendan Curti, M.D.
Regeneron Pharmaceuticals, Inc.
  • Providence Cancer Institute Franz Clinic