A Phase 1 Study of FOR46 in Patients With Metastatic Castration-Resistant Prostate Cancer (mCRPC)

• ClinicalTrials.gov Identifier: NCT03575819
• Recruitment Status: Recruiting
• First Posted: July 3, 2018
• Last Update Posted: August 19, 2021
• Sponsor: Fortis Therapeutics, Inc.
• Information provided by (Responsible Party): Fortis Therapeutics, Inc.

Tracking Information

• First Submitted Date: June 20, 2018
• First Posted Date: July 3, 2018
• Last Update Posted Date: August 19, 2021
• Actual Study Start Date: February 4, 2019
• Estimated Primary Completion Date: May 31, 2022 (Final data collection date for primary outcome measure)

Current Primary Outcome Measures (submitted: June 29, 2018)

• Occurrence of toxicity [ Time Frame: Through 1 month following last dose ]
  Type, incidence, severity, seriousness, and relatedness of adverse events.
• Occurrence of dose-limiting toxicities [ Time Frame: Through 1 month following last dose ]
  The severity and incidence of dose-limiting toxicities related to escalating dose levels of FOR46
• Disease response/composite response [ Time Frame: 12 months ]
  Decline in serum prostate-specific antigen greater than 50% from baseline, confirmed by repeat measurement and objective response rate by Response Evaluation Criteria in Solid Tumors (RECIST)

• Original Primary Outcome Measures: Same as current

Current Secondary Outcome Measures (submitted: June 29, 2018)

• Characterize FOR46 plasma concentration [ Time Frame: Through 1 month following last dose ]
  FOR46 maximum plasma concentration
• Characterize the FOR46 area under the curve [ Time Frame: Through 1 month following last dose ]
  FOR46 area under the plasma concentration-time curve
• Characterize FOR46 elimination [ Time Frame: Through 1 month following last dose ]
  FOR46 elimination half-life
• Antidrug Antibodies [ Time Frame: Through 1 month following last dose ]
  Change from baseline in serum levels of antidrug antibodies
• Median radiographic progression-free survival [ Time Frame: 12 months ]
  Assessed by Prostate Cancer Clinical Trials Working Group 3 criteria

• Original Secondary Outcome Measures: Same as current

Current Other Pre-specified Outcome Measures (submitted: June 29, 2018)

Exploratory Endpoint: Tumor expression of CD46 [ Time Frame: Through 1 month following last dose ]

Association between level of tumor expression of CD46 by immunohistochemistry (IHC) analysis with clinical outcomes

• Original Other Pre-specified Outcome Measures: Same as current

Descriptive Information

• Brief Title: A Phase 1 Study of FOR46 in Patients With Metastatic Castration-Resistant Prostate Cancer (mCRPC)
• Official Title: A Phase 1 Study of FOR46 Administered Every 21 Days in Patients With Metastatic Castration-Resistant Prostate Cancer (mCRPC)

Brief Summary

This study will test the safety and efficacy of FOR46 given every 21 days to patients with metastatic castration-resistant prostate cancer.

The name of the study drug involved in this study is: FOR46 for Injection (FOR46)

Detailed Description

This study is designed to evaluate the safety, tolerability and antitumor activity of FOR46 in patients with metastatic castration-resistant prostate cancer. This study will be conducted in two parts:

Dose escalation:

This part will evaluate increasing doses of FOR46 to identify the maximum tolerated dose (MTD). The first patient enrolled on the study will receive the lowest dose of FOR46. Once this dose is shown to be safe, a second patient will be enrolled at the next higher dose. Patients will continue to be enrolled into either single or multiple patient groups receiving increasing doses until the MTD is reached.

Dose expansion:

This part of the study will further evaluate the safety, tolerability and antitumor activity of FOR46 at a dose shown to be safe in the dose escalation part of the study. Patients will be enrolled into 1 of 2 groups, based on histology.

• Study Type: Interventional
• Study Phase: Phase 1

Study Design

Allocation: Non-Randomized
Intervention Model: Sequential Assignment
Intervention Model Description:

Following completion of the dose escalation phase of the study and determination of a recommended phase 2 dose, patients will be enrolled into a dose expansion cohort.

Masking: None (Open Label)
Primary Purpose: Treatment

• Condition: Prostate Cancer Metastatic

Intervention

Drug: FOR46

FOR46 is an intravenously (IV) administered antibody-drug conjugate (ADC) directed against CD46

Study Arms

• Experimental: FOR46 (Dose Escalation)
  Eligible patients will receive FOR46 administered as an IV infusion every 21 days. Patients will be enrolled into escalating dose levels during the Dose Escalation period of the study.
  Intervention: Drug: FOR46
• Experimental: FOR46 (Dose Expansion)
  Eligible patients will receive FOR46 administered as an IV infusion every 21 days. Patients will receive the maximum tolerated dose during the Dose Expansion period of the study.
  Intervention: Drug: FOR46

• Publications *: Not Provided

Recruitment Information

• Recruitment Status: Recruiting
• Estimated Enrollment (submitted: August 17, 2021): 66
• Original Estimated Enrollment (submitted: June 29, 2018): 60
• Estimated Study Completion Date: September 30, 2022
• Estimated Primary Completion Date: May 31, 2022 (Final data collection date for primary outcome measure)

Eligibility Criteria

Inclusion Criteria:

• Male ≥ 18 years of age
• Has histologically confirmed prostate cancer that is metastatic and has progressed as defined by PCWG3 criteria during or after treatment with at least 1 ASI (eg, abiraterone, enzalutamide, apalutamide), or another second-generation anti-androgen or cytochrome P450 (CYP)17A1 inhibitor, with the most recent ASI administered in the castration-resistant setting
• Has serum testosterone levels < 50 ng/dL during screening. Patients without a history of bilateral orchiectomy are required to remain on luteinizing hormone-releasing hormone (LHRH) analog during the course of protocol therapy
• ECOG performance status of 0 or 1
• Adequate hematologic, renal and hepatic function
• Males with female partners of childbearing potential must agree to use 2 effective methods of contraception
• Patients must provide signed informed consent
• Patients enrolled into the dose expansion phase must have prostate carcinoma without histologic evidence of small-cell/neuroendocrine carcinoma features on prior biopsy or must have unequivocal histologic evidence of small-cell/neuroendocrine prostate carcinoma (pure or mixed). Patients with treatment-emergent small-cell neuroendocrine cancer (pure or mixed) may have received no more than on prior chemotherapy regimen for mCRPC
• Patients enrolled into the dose expansion phase must be willing to undergo a metastatic tumor biopsy or has tissue available from a prior post-castration resistant tumor biopsy

Exclusion Criteria:

• Persistent clinically significant toxicities from previous anticancer therapy
• Has NCI CTCAE Grade ≥ 2 peripheral neuropathy from any etiology or has a genetic disorder that is associated with peripheral neuropathy even without current neuropathic manifestations
• Prior treatment with cytotoxic chemotherapy for mCRPC (chemotherapy in the hormone-sensitive setting is allowed if > 6 months before study entry)
• Has received external-beam radiation or systemic anticancer therapy within 14 days before first dose of FOR46
• Has received treatment with an investigational drug within 28 days before first dose of FOR46
• Has had a major surgical procedure within 28 days before administration of FOR46 dose
• Clinically significant cardiovascular disease
• Uncontrolled, clinically significant pulmonary disease
• Has a history of brain or leptomeningeal metastases.
• Uncontrolled intercurrent illness
• Has a known positive status for HIV or either active/chronic hepatitis B/C
• Requires medications that are strong inhibitors or strong inducers of CYP3A4
• [Dose escalation only] Has a history of episodic atrial fibrillation or flutter (patients with chronic atrial fibrillation are not excluded)

Sex/Gender

• Sexes Eligible for Study: Male
• Gender Based Eligibility: Yes

• Ages: 18 Years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Contacts

Contact: Andrew Dorr, MD; 858-504-1453; adorr414@me.com

Contact: Jill Abbey; 925-286-0832; jill.abbey@gmail.com

• Listed Location Countries: United States

Administrative Information

• NCT Number: NCT03575819
• Other Study ID Numbers: FOR46-001
• Has Data Monitoring Committee: Yes

U.S. FDA-regulated Product

• Studies a U.S. FDA-regulated Drug Product: Yes
• Studies a U.S. FDA-regulated Device Product: No

IPD Sharing Statement

• Plan to Share IPD: No

• Responsible Party: Fortis Therapeutics, Inc.
• Study Sponsor: Fortis Therapeutics, Inc.
• Collaborators: Not Provided

Investigators

• Study Director: Andrew Dorr, MD; Fortis Therapeutics, Inc.

• PRS Account: Fortis Therapeutics, Inc.
• Verification Date: August 2021