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

A Phase 2 Dose Optimization Trial Evaluating a CD46-Targeted Antibody-Drug Conjugate (FG-3246) in Patients With Metastatic Castration-Resistant Prostate Cancer

Status
Recruiting
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06842498
Enrollment
75
Registered
2025-02-24
Start date
2026-02-22
Completion date
2028-03-31
Last updated
2026-08-17

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Metastatic Castration-Resistant Prostate Cancer

Keywords

FG-3246, FOR46, mCRPC, CRPC, CD46, Prostate cancer, Antibody-drug conjugate, Metastatic prostate cancer, FibroGen, ADC, Kyntra, Kyntra Bio, KYNB

Brief summary

The purpose of this study is to evaluate the safety, efficacy, tolerability, and pharmacokinetics (PK) of FG-3246, a cluster of differentiation 46 (CD46) targeting antibody-drug conjugate (ADC), in the treatment of participants with mCRPC who have progressed following treatment with one prior second-generation androgen receptor signaling inhibitor (ARSI) in any setting and no prior taxane therapy in the mCRPC setting.

Interventions

DRUGFG-3246

FG-3246 will be administered per schedule specified in the arm description.

Sponsors

Kyntra Bio
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
MALE
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

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.

Design outcomes

Primary

MeasureTime frame
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) CriteriaUntil 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)

Secondary

MeasureTime frame
rPFS Rate at 6 Months (rPFS6) Per RECIST v1.1 and PCWG3 CriteriaMonth 6
rPFS Rate at 12 Months (rPFS12) Per RECIST v1.1 and PCWG3 CriteriaMonth 12
Confirmed Objective Response Rate (ORR) Per RECIST v1.1 and PCWG3 CriteriaFrom first dose up to approximately 25 months
Duration of Response (DoR) Per RECIST v1.1 and PCWG3 CriteriaFrom first dose up to approximately 25 months
Confirmed PSA50 Response Rate: Percentage of Participants Achieving a Decline in Prostate-specific Antigen (PSA) ≥50% From BaselineUp to approximately 25 months
Confirmed PSA90 Response Rate: Percentage of Participants Achieving a Decline in PSA ≥90% From BaselineUp to approximately 25 months
Composite Response Rate (CRR) Per RECIST 1.1 and PCWG3 CriteriaUp to approximately 25 months
PSA Progression-free Survival (PFS)Up to approximately 25 months
Disease Control Rate (DCR) per RECIST 1.1 and PCWG3 CriteriaUp to approximately 25 months
Clinical Benefit Rate (CBR) per RECIST 1.1 and PCWG3 CriteriaUp to approximately 25 months
Time to First Symptomatic Skeletal-related Event (SSRE)Up to approximately 25 months
Overall Survival (OS)Until death or up to approximately 25 months
Percentage of Participants Who Develop Anti-drug Antibodies (ADA) and Neutralizing Antibody (NAb) Against FG-3246Within each 21 day treatment cycle from Cycle 1 through 28 days post last dose (up to approximately 25 months)

Countries

United States

Contacts

CONTACTJavier Moreno
jmoreno@kyntrabio.com415-978-1466
CONTACTMairead Carney
mcarney@kyntrabio.com415-978-1337

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Aug 18, 2026