A Study of FG-3246 in Participants With Metastatic Castration-Resistant Prostate Cancer (mCRPC)

The film gives the main points. The full list below is copied from the registry; the study team makes the final decision.

• Age18 Years to no maximum
• SexMale
• Healthy volunteersNo

You may be able to join if

• Key Inclusion Criteria:
• Participant must have histological, and/or cytological confirmation of prostate adenocarcinoma on all prior tumor biopsies.
• Participant with soft tissue disease and a safely accessible soft tissue tumor lesion(s) must agree to biopsy of a primary or metastatic lesion during screening. Alternatively, participant may provide a suitable archival biopsy of a primary or metastatic lesion.
• Participant must have serum testosterone levels <50 nanograms (ng)/deciliter (dL) during screening.
• Participant is required to have progressed on no more than one prior treatment with a second generation ARSI (abiraterone acetate, enzalutamide, apalutamide, or darolutamide) initiated in either the castration-sensitive or castration-resistant setting.
• Participant must have progressive mCRPC following last treatment at screening.
• Participant must have ≥1 metastatic lesion that is present on baseline Computed Tomography (CT), Magnetic Resonance Imaging (MRI), or bone scan obtained ≤28 days prior to randomization.
• Participant must have adequate organ function during screening.
• Key Exclusion Criteria:
• Participant has received previous treatment with a therapeutic targeting CD46.
• Participant has small cell neuroendocrine carcinoma (pure or mixed) on any prior histologic evaluation of primary or metastatic lesion.
• Participant has progressed on more than one prior second-generation ARSI in any setting or has received more than two prior second-generation ARSIs in any setting.
• Participants must not have received recent anticancer treatments before enrollment. Ongoing supportive or hormonal therapies are allowed if they were started well before randomization and are continued without change.
• Participant has received any prior radiation therapy within 14 days prior to randomization.
• Participant has a known actionable mutation or gene alteration, for example, BRCA1 mutation, for which approved therapies are available, for example, PARP inhibitors, unless these therapies are not appropriate for the participant as determined by the investigator or the participant refuses such therapy.
• Participant has National Cancer institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) ≥Grade 2 peripheral neuropathy at the time of screening from any etiology.
• Participant has received any prior chemotherapy; however, one prior taxane-based chemotherapy in the castration-sensitive setting is allowed if completed >12 months before randomization.
• Participant has known hypersensitivity to the components of FG-3246 or its analogs or a history of allergic or anaphylactic reaction to human, humanized, or chimeric monoclonal antibodies.
• Participant has diagnosis with any other malignancy in the past 5 years, except for adequately treated basal cell or squamous cell carcinoma of the skin.
• Participant requires treatment with a strong cytochrome P450 3A4 (CYP3A4) inhibitor or inducer drug that cannot be safely discontinued.
• NOTE: Other protocol-defined inclusion/exclusion may apply.

This is how the treatment is meant to work. Whether it helps, and how safe it is, is what this trial is testing.

anti-CD46 antibody-drug conjugate FOR46. An antibody-drug conjugate (ADC) composed of a human monoclonal antibody directed against the cluster of differentiation 46 (CD46; membrane cofactor protein; MCP) and conjugated to an as of yet undisclosed cytotoxic payload, with potential antineoplastic activity. Upon administration, anti-CD46 ADC FOR46 specifically targets and binds to a specific conformational epitope on the immune modulatory receptor CD46 expressed on certain tumor cells. Upon binding and internalization, the cytotoxic payload kills the CD46-expressing tumor cells. The conformational epitope of CD46 is highly expressed in multiple tumor cell types while minimally expressed or absent in normal, healthy tissues. FOR46 does not interfere with other CD46-mediated pathways that naturally occur in normal, healthy tissues. NCI Drug Dictionary

Treatments listed in the registry

• FG-3246 (Drug): FG-3246 will be administered per schedule specified in the arm description.

Randomized · Parallel · masking: None

Main goals

• Radiographic Progression-free Survival (rPFS) By Investigator Assessment Per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 and Prostate Cancer Clinical Trials Working Group 3 (PCWG3) Criteria (Until radiographic progression is noted (up to approximately 25 months))
• Number of Participants With Treatment-emergent Adverse Events (TEAEs) (From first dose until 28 days after last dose (up to approximately 25 months))
• Maximum Plasma Concentration (Cmax) of FG-3246, Total Anti-cluster of Differentiation 46 Antibody (CD46), and Free Monomethyl Auristatin E (MMAE) (Within each 21 day treatment cycle from Cycle 1 through 28 days post last dose (up to approximately 25 months))

Other goals

• rPFS Rate at 6 Months (rPFS6) Per RECIST v1.1 and PCWG3 Criteria
• rPFS Rate at 12 Months (rPFS12) Per RECIST v1.1 and PCWG3 Criteria
• Confirmed Objective Response Rate (ORR) Per RECIST v1.1 and PCWG3 Criteria
• Duration of Response (DoR) Per RECIST v1.1 and PCWG3 Criteria
• Confirmed PSA50 Response Rate: Percentage of Participants Achieving a Decline in Prostate-specific Antigen (PSA) ≥50% From Baseline
• Confirmed PSA90 Response Rate: Percentage of Participants Achieving a Decline in PSA ≥90% From Baseline
• Composite Response Rate (CRR) Per RECIST 1.1 and PCWG3 Criteria
• PSA Progression-free Survival (PFS)
• Disease Control Rate (DCR) per RECIST 1.1 and PCWG3 Criteria
• Clinical Benefit Rate (CBR) per RECIST 1.1 and PCWG3 Criteria
• Time to First Symptomatic Skeletal-related Event (SSRE)
• Overall Survival (OS)
• Percentage of Participants Who Develop Anti-drug Antibodies (ADA) and Neutralizing Antibody (NAb) Against FG-3246

Planned enrollment: 75 (estimated).

• Western Regional Medical Center - City of Hope Phoenix Goodyear, Goodyear, Arizona
• HonorHealth Research Institute, Scottsdale, Arizona
• The University of Arizona Cancer Center - North Campus, Tucson, Arizona
• VA Greater Los Angeles Healthcare System, Los Angeles, California
• UCLA Clark Urology Center, Los Angeles, California
• University of California San Francisco, San Francisco, California
• New Haven Hospital - Yale Cancer Center, New Haven, Connecticut
• Bioresearch Partner - Aventura, Aventura, Florida
• Bioresearch Partner - Hialeah, Hialeah, Florida
• Biogenix Molecular, LLC, Miami, Florida
• Winship Cancer Institute, Emory University, Atlanta, Georgia
• East Jefferson General Hospital Metairie, New Orleans, Louisiana
• New Mexico Oncology Hematology Consultants, Ltd., Albuquerque, New Mexico
• Duke University Medical Center - Duke Cancer Center, Durham, North Carolina
• University Hospitals Cleveland Medical Center, Cleveland, Ohio
• Carolina Urologic Research Center, Myrtle Beach, South Carolina
• Henry-Joyce Cancer Clinic, Nashville, Tennessee
• University of Texas Southwestern Medical Center, Dallas, Texas
• Oncology Consultants, Houston, Texas
• University of Virginia Comprehensive Cancer Center, Charlottesville, Virginia
• Fred Hutchinson Cancer Center, Seattle, Washington
• University of Washington Medical Center, Seattle, Washington
• Northwest Medical Specialties, PLLC - Tacoma, Tacoma, Washington

Site status as of Oct 30, 2026. Check the live record before contacting a site.

• ClinicalTrials.gov NCT06842498
• NCI Drug Dictionary: C156416

Registry record reviewed as fetched Oct 30, 2026, last updated by the sponsor Aug 16, 2026. Public record; not medical advice.