REGN4336 (a PSMAXCD3 Bispecific Antibody) Administered Alone or in Combination With Cemiplimab in Adult Male Patients With Metastatic Castration-Resistant Prostate Cancer

• Status: Not yet recruiting
• Trial end date: 2026-08-04
• Target enrollment: 0
• Participant gender: Male

Summary

The primary objective of the study is:

Dose Escalation:

• To assess the safety, tolerability, and pharmacokinetics (PK) and to determine recommended phase 2 dosing regimen (RP2DR) of REGN4336 separately as monotherapy or in combination with cemiplimab

Dose Expansion:

• To assess preliminary anti-tumor activity of REGN4336 as monotherapy or in combination with cemiplimab as measured by objective response rate (ORR) per modified Prostate Cancer Working Group (PCWG3) criteria

The secondary objectives of the study are:

Dose Escalation:

• To assess preliminary anti-tumor activity of REGN4336 as monotherapy or in combination with cemiplimab as measured by ORR per modified PCWG3 criteria

Dose Expansion:

• To characterize the safety profile in each expansion cohort

• To characterize the PK of REGN4336 as monotherapy or in combination with cemiplimab

In both Dose Escalation and Dose Expansion:

• To assess preliminary anti-tumor activity of REGN4336 as monotherapy or in combination with cemiplimab as measured by prostate specific antigen (PSA) decline

• To evaluate immunogenicity of REGN4336 in Module 1 and immunogenicity of REGN4336 and cemiplimab in Module 2

• Phase: Phase 1/Phase 2
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: Regeneron Pharmaceuticals
• Treatments: Cemiplimab

Criteria

Key Inclusion Criteria:

1. Histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma

2. Metastatic, castration-resistant prostate cancer (mCRPC) with PSA value at screening ≥4 ng/mL that has progressed within 6 months prior to screening as defined in the protocol

3. Has progressed upon or intolerant to ≥2 lines prior systemic therapy approved in the metastatic and/or castration-resistant setting (in addition to androgen deprivation therapy [ADT]) including at least one second-generation anti-androgen therapy (e.g. abiraterone, enzalutamide, apalutamide, or darolutamide)

Key Exclusion Criteria:

1. 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

2. Has received any previous systemic biologic therapy within 5 half-lives of first dose of study therapy

3. Has received prior PSMA-targeting therapy

4. 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

5. Ongoing or recent (within 5 years) evidence of significant autoimmune disease that required treatment with systemic immunosuppressive treatments

6. Encephalitis, meningitis, neurodegenerative disease (with the exception of mild dementia that does not interfere with activities of daily living [ADLs]) or uncontrolled seizures in the year prior to first dose of study therapy

7. 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