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NCT Number: NCT07719361

A Study in Patients With Metastatic Castration-Resistant Prostate Cancer

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.

Recruiting

Interested in participating?

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Key information

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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.

Exclusion criteria

  • 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.

Treatment and study plan

FX-111

Drug

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

Primary outcomes

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

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

Secondary outcomes

  1. Area Under the Concentration Time Curve

    Time frame: Study day 1 throughout the study for 6 months.

    Total body exposure of FX-111

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

    Time frame: Study day 1 throughout the study for 6 months.

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

    Time frame: Study day 1 throughout the study for 6 months.

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

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

  5. Objective Response Rate (ORR)

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

    The number of patients who achieve either a Complete Response (CR) or Partial Response (PR) to FX-111.

    CR: disappearance of all lesions and pathologic lymph nodes. PR: ≥30% decrease in sum of lesions, no new lesions, no progression of non-target lesions.

  6. Duration of Response (DoR)

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

    DoR is the time from initial CR or PR until disease progression.

Study contacts

Contact information is provided by the study sponsor or research team.

Carolyn McCrone, Sr Clinical Trial Associate

CONTACT

[email protected]

857-706-4400

Janine Koucheki, Associate Director, Clinical Operations

CONTACT

[email protected]

857-706-4400

Sponsors and collaborators

Lead sponsor

Flare Therapeutics Inc.

Industry

Registry information

Official study title

A Phase 1, First-in-Human, Dose-Finding Study to Evaluate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of FX-111 in Patients With Metastatic Castration-Resistant Prostate Cancer

Important dates

Study start
2026
Primary completion
2028
Study completion
2029
First posted
Jul 22, 2026
Registry last updated
Jul 24, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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