A Study in Patients With Metastatic Castration-Resistant Prostate Cancer

NCT07719361 | Recruiting Phase 1 DMC FDA Drug

• 1 other identifier: FX-111-CLINPRO-1
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 10

Brief Summary

The goal of this clinical trial is to find out if FX-111 is safe enough to permit further studies in adult male participants with metastatic castration-resistant prostate cancer (mCRPC). It will also study the drug's pharmacokinetics (how the body breaks down FX-111) and how well FX-111 treats mCRPC. The main questions it aims to answer are: What are the side effects of FX-111? Does FX-111 work to reduce or prevent progression of mCRPC? The study doctor will oversee participants' treatment with FX-111 and ask about any side effects. Participants will take FX-111 every day by mouth and will have regular physical and laboratory examinations to check health and tumor status.

Conditions

Metastatic Castration Resistant Prostate Cancer; mCRPC; mCRPC (Metastatic Castration-resistant Prostate Cancer); Prostatic Neoplasms; Prostatic Neoplasms, Castration-Resistant; mCRPC or Advanced/Metastatic Solid Tumors; mCRPC, Metastatic Castration Resistant Prostate Cancer; Neoplasms Prostate; Neoplasms of Prostate

Outcome Measures

Primary Outcomes (1)

• The number of adverse events (AEs), serious adverse events (SAEs), and drug withdrawal due to AE in participants receiving FX-111

  Study day 1 throughout the study, estimated to be 6 months.

Secondary Outcomes (6)

• Area Under the Concentration Time Curve

  Study day 1 throughout the study for 6 months.

• Maximum concentration (Cmax) of FX-111 in the bloodstream.

  Study day 1 throughout the study for 6 months.

• Time required (Tmax) to reach Cmax of FX-111 in the bloodstream.

  Study day 1 throughout the study for 6 months.

• Rate of confirmed prostate-specific antigen (PSA) decline of ≥ 50% from baseline (PSA50).

  Baseline and every 4 weeks throughout the study, estimated to be 6 months.

• Objective Response Rate (ORR)

  Tumor assessments at baseline and every 8 weeks throughout the study, estimated to be 6 months.

Study Arms (5)

FX-111 Dose Level 1

EXPERIMENTAL

Drug: FX-111

FX-111 Dose Level 2

EXPERIMENTAL

Drug: FX-111

FX-111 Dose Level 3

EXPERIMENTAL

Drug: FX-111

FX-111 Dose Level 4

EXPERIMENTAL

Drug: FX-111

FX-111 Dose Level 5

EXPERIMENTAL

Drug: FX-111

Interventions

FX-111 DRUG

FX-111 will be administered orally once daily in continuous 28-day cycles.

FX-111 Dose Level 1; FX-111 Dose Level 2; FX-111 Dose Level 3; FX-111 Dose Level 4; FX-111 Dose Level 5

Eligibility Criteria

• Age: 18 Years+
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Confirmed adenocarcinoma of the prostate.
• PSA levels ≥ 2 ng/mL at screening visit.
• Progressing PSA, defined as two consecutive increases in the most recent PSA measurements taken at least 1 week apart.
• Progressed on Androgen Deprivation Therapy (ADT) and at least one prior potent Androgen Receptor (AR) pathway inhibitor given in castration-sensitive prostate cancer setting or approved for castration-resistant prostate cancer (eg, apalutamide, darolutamide, abiraterone, enzalutamide).
• Ongoing primary ADT with gonadotropin-releasing hormone agonist or antagonist in the absence of bilateral orchiectomy.
• Acceptable physical functioning and laboratory measurements, per the study protocol.
• Discontinued prior therapies within protocol-specified timeframes.
• Commit to use of highly-effective contraception while on study and for 90 days after.
• Willing and able to adhere to the study visit schedule and other protocol defined requirements.

You may not qualify if:

• Predominance of small cell carcinoma of the prostate/neuroendocrine prostate cancer in most recent tumor biopsy.
• Participants with brain metastases that require ongoing treatment with radiation or high-dose steroids.
• Not recovered from side effects of prior surgery or cancer treatments.
• Evidence of active viral, bacterial, or fungal infection requiring treatment with antivirals, antibiotics, or anti-fungal medications.
• Prior treatment with AR degraders and molecules with an AR ligand such as AR Regulated Induced Proximity Targeting Chimera (RIPTAC).
• Blood clots ≤ 4 weeks prior to start of treatment.
• Concurrent malignancy requiring treatment or history of prior malignancy active within 2 years prior to the first dose of study drug. Patients may be eligible if the malignancy is clinically stable or has been treated with curative intent.
• Any evidence of severe or uncontrolled systemic diseases.
• Any condition that, in the opinion of the Investigator, would interfere with evaluation of the investigational product or interpretation of the patient's safety or study results.

Sponsors & Collaborators

• Flare Therapeutics Inc.: lead

Study Sites (10)

START Los Angeles

Los Angeles, California, 90025, United States

RECRUITING

Massachusetts General Hospital

Boston, Massachusetts, 02114, United States

NOT YET RECRUITING

START Midwest

Grand Rapids, Michigan, 49546, United States

RECRUITING

START New Jersey

East Brunswick, New Jersey, 08816, United States

RECRUITING

START Carolinas

Myrtle Beach, South Carolina, 29572, United States

RECRUITING

Tennessee Oncology

Nashville, Tennessee, 37203, United States

NOT YET RECRUITING

START Dallas-Fort Worth

Fort Worth, Texas, 76104, United States

RECRUITING

NEXT Houston

Houston, Texas, 77054, United States

NOT YET RECRUITING

NEXT Oncology

San Antonio, Texas, 78229, United States

NOT YET RECRUITING

NEXT Virginia

Fairfax, Virginia, 22031, United States

NOT YET RECRUITING

MeSH Terms

Conditions

Prostatic Neoplasms; Prostatic Neoplasms, Castration-Resistant

Condition Hierarchy (Ancestors)

Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Genital Diseases; Urogenital Diseases; Prostatic Diseases; Male Urogenital Diseases

Central Study Contacts

Janine Koucheki, Associate Director, Clinical Operations

CONTACT

857-706-4400; clinops@flaretx.com

Carolyn McCrone, Sr Clinical Trial Associate

CONTACT

857-706-4400; clinops@flaretx.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SEQUENTIAL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 17, 2026
• First Posted: July 22, 2026
• Study Start: July 1, 2026
• Primary Completion (Estimated): February 15, 2028
• Study Completion (Estimated): February 15, 2029
• Last Updated: July 24, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

US (10)