A Study to Learn How Enzalutamide, Apalutamide and Bicalutamide Affect the Way Fezolinetant is Processed in Men With Prostate Cancer

NCT07783282 | Not Yet Recruiting Phase 1

• 2 other identifiers: 2693-CL-21012024-520286-31
• Study Type: interventional
• Target: 56
• Locations: 0 countries
• Sites: N/A

Brief Summary

Hormone therapy, or androgen deprivation therapy (ADT) is a standard way to treat prostate cancer. It works by reducing the amount of testosterone in the body. One of the side effects of hormone therapy is hot flashes. There is an unmet medical need to treat hot flashes in men undergoing hormone therapy for prostate cancer. This study will help researchers understand if hormone therapy (enzalutamide, apalutamide or bicalutamide) affects the way fezolinetant is processed by the body in men with prostate cancer. The main aim of this study is checking levels of fezolinetant in the blood over time to learn how long it takes to get into the blood, spread through the body and be cleared from the body. Men with prostate cancer or healthy men can take part. The men with prostate cancer will have already been taking standard hormone therapy (enzalutamide, apalutamide or bicalutamide) for a few months. Men cannot take part if they have recently had major surgery, have had an infection, have a heart condition, or have gut problems. Men with prostate cancer cannot take part if they have other cancers, have recently had certain treatments for prostate cancer, have certain ongoing medical conditions or any chronic disease. This includes any liver problems. There will be 4 groups in this study: Group 1 - men with prostate cancer who are taking enzalutamide will be given fezolinetant. Group 2 - men with prostate cancer who are taking apalutamide will be given fezolinetant. Group 3 - men with prostate cancer who are taking bicalutamide will be given fezolinetant. Group 4 - healthy men will only be given fezolinetant. The men taking part in the study will stay in the clinic for a few days and nights. The men will have nothing to eat or drink for several hours before taking 1 tablet of fezolinetant. Blood samples will be taken and health checks done. During their stay, the men with prostate cancer will continue to be given the standard dose of their hormone therapy. All the men in the study will continue to have regular health checks and will be asked if they have any medical problems. After the men leave the clinic, they will return to the clinic about a week later for a final health check.

Conditions

Prostate Cancer

Keywords

Prostate Cancer; ESN364; fezolinetant; VEOZAH™; Pharmacokinetics; Healthy Volunteer

Outcome Measures

Primary Outcomes (2)

• Pharmacokinetics (PK) of Fezolinetant in plasma: Maximum Concentration (Cmax)

  Cmax will be recorded from the PK plasma samples collected.

  Up to Day 3

• PK of Fezolinetant in plasma: Area under the concentration-time curve from the time of dosing extrapolated to time infinity (AUCinf)

  AUCinf will be recorded from the PK plasma samples collected.

  Up to Day 3

Secondary Outcomes (7)

• Number of participants with Adverse Events (AEs)

  Up to Day 12

• Number of participants with laboratory value abnormalities and/or adverse events (AEs)

  Up to Day 12

• Number of participants with vital sign abnormalities and/or adverse events (AEs)

  Up to Day 12

• Number of participants with electrocardiogram (ECG) abnormalities and/or Adverse Events (AEs)

  Up to Day 12

• PK of metabolite ES259564 in plasma: Cmax

  Up to Day 3

Study Arms (4)

Prostate cancer participants taking enzalutamide

EXPERIMENTAL

Participants with prostate cancer taking a stable dose of enzalutamide will receive a single dose of fezolinetant on day 1.

Drug: fezolinetant; Drug: enzalutamide; Drug: GnRH agonist/antagonist

Prostate cancer participants taking apalutamide

EXPERIMENTAL

Participants with prostate cancer taking a stable dose of apalutamide will receive a single dose of fezolinetant on day 1.

Drug: fezolinetant; Drug: apalutamide; Drug: GnRH agonist/antagonist

Prostate cancer participants taking bicalutamide

EXPERIMENTAL

Participants with prostate cancer taking a stable dose of bicalutamide will receive a single dose of fezolinetant on day 1.

Drug: fezolinetant; Drug: bicalutamide; Drug: GnRH agonist/antagonist

Healthy male participants

EXPERIMENTAL

Healthy male participants will receive a single dose of fezolinetant on day 1.

Drug: fezolinetant

Interventions

fezolinetant DRUG

oral

Also known as: ESN364, VEOZAH™

Healthy male participants; Prostate cancer participants taking apalutamide; Prostate cancer participants taking bicalutamide; Prostate cancer participants taking enzalutamide

enzalutamide DRUG

oral

Also known as: MDV3100, Xtandi™

Prostate cancer participants taking enzalutamide

apalutamide DRUG

oral

Prostate cancer participants taking apalutamide

bicalutamide DRUG

oral

Prostate cancer participants taking bicalutamide

GnRH agonist/antagonist DRUG

Per local product label

Prostate cancer participants taking apalutamide; Prostate cancer participants taking bicalutamide; Prostate cancer participants taking enzalutamide

Eligibility Criteria

• Age: 50 Years - 75 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Participant is born male, inclusive of all gender ideologies.
• Male participant must agree to use contraception with female partner(s) of childbearing potential (including breastfeeding partner) throughout the treatment period and for 30 days after final fezolinetant administration.
• Male participant must agree to remain abstinent or use a condom with pregnant partner(s) for the duration of the pregnancy throughout the investigational period and for 30 days after final study intervention administration.
• Male participant must not donate sperm during the treatment period and for 30 days after final study intervention administration.
• Participant agrees not to participate in another interventional study while participating in the present study.
• Participant has a body mass index (BMI) range of 18.5 to 30.0 kg/m\^2 inclusive and weighs at least 50 kg at screening.
• Participant is diagnosed with histologically or cytologically confirmed adenocarcinoma of the prostate.
• Participant must be receiving concurrent gonadotropin-releasing hormone (GnRH) agonist or antagonist therapy for a minimum of 3 months prior to study intervention on day 1 and be planning to continue on the therapy for the duration of the study.
• Participant has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 at screening.
• Participant is receiving concurrent and stable enzalutamide, apalutamide or bicalutamide for at least 3 months prior to study intervention on day 1, which must be continued throughout the study.
• Participant has at least 6-month life expectancy.
• Participant is healthy and has no clinically significant medical conditions based on the physical examination, electrocardiograms (ECGs) and protocol-defined clinical laboratory tests at screening or on day -1.

You may not qualify if:

• Participant has had major surgery (e.g., requiring general anesthesia) within 90 days before screening, or will not have fully recovered from surgery, or has surgery planned during the time the participant is expected to participate in the study or within 5 half-lives (approximately 2 days) after the last dose of study drug administration or end-of-study visit (ESV), whichever is longer.
• Participant has/had febrile illness or symptomatic, viral, bacterial (including upper respiratory infection) or fungal (noncutaneous) infection within 28 days prior to day -1.
• Participant has a history of drug or alcohol abuse according to Diagnostic and Statistical Manual (American Psychiatric Association), Fifth Edition (DSM-5) criteria within 2 years before screening.
• Participant has a history of unexplained syncope, cardiac arrest, unexplained cardiac arrhythmias or torsades de pointes, structural heart disease or a family history of long QT syndrome.
• Participant has a gastrointestinal disorder affecting absorption.
• Participant has present exposure or history of participation in a study of the study intervention (fezolinetant) or previous exposure to fezolinetant within 28 days prior to day -1.
• Participant has received any investigational therapy within 90 days or 5 half-lives, whichever is longer, prior to screening
• Participant tests positive for alcohol at screening or on day -1.
• Participant has a positive serology test for hepatitis A virus (HAV) antibodies (immunoglobulin M (IgM)), hepatitis B (HBc) antibodies, hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibodies or antibodies to human immunodeficiency virus (HIV) type 1 and/or type 2 at screening.
• Participant tests positive for drugs of abuse (e.g., amphetamines, barbiturates, benzodiazepines, cocaine, opiates and cannabinoids) at screening or on day -1.
• Participant has a positive result for Severe Acute Respiratory Syndrome Coronavirus-2 (novel coronavirus causing COVID-19 disease) (SARS-CoV-2) test at screening or on day -1.
• Participant has creatinine \> 1.5 x upper limit of normal (ULN) or estimated glomerular filtration rate (eGFR) \< 60 mL/min/1.73 m\^2 using the Modification of Diet in Renal Disease formula at the screening visit.
• Participant has active liver disease, jaundice, or elevated liver aminotransferase (ATs) (alanine aminotransferase (ALT) or aspartate aminotransferase (AST)), elevated total bilirubin (TBL) or direct bilirubin (DBL), or elevated alkaline phosphatase (ALP) at screening. A participant with mildly elevated ALT or AST up to \< 1.5 x ULN can be enrolled if TBL and DBL are normal. Participant with mildly elevated ALP (up to \< 1.5 x ULN) can be enrolled if cholestatic liver disease is excluded and no cause other than fatty liver is diagnosed. Participant with Gilbert's syndrome with elevated TBL may be enrolled as long as DBL, hemoglobin and reticulocytes are normal.
• Participant has any condition which makes the participant unsuitable for study participation.
• Participant regularly consumes \> 200 mg of caffeine per day.

Sponsors & Collaborators

• Astellas Pharma Global Development, Inc.: lead

MeSH Terms

Conditions

Prostatic Neoplasms

Interventions

fezolinetant; enzalutamide; apalutamide; bicalutamide; Gonadotropin-Releasing Hormone

Condition Hierarchy (Ancestors)

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

Intervention Hierarchy (Ancestors)

Pituitary Hormone-Releasing Hormones; Hypothalamic Hormones; Peptide Hormones; Hormones; Hormones, Hormone Substitutes, and Hormone Antagonists; Neuropeptides; Peptides; Amino Acids, Peptides, and Proteins; Oligopeptides; Nerve Tissue Proteins; Proteins

Study Officials

• Medical Monitor

  Astellas Pharma Global Development, Inc.

  STUDY DIRECTOR

Central Study Contacts

Astellas Pharma Global Development, Inc.

CONTACT

800-888-7704; Astellas.registration@astellas.com

Study Design

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

Study Record Dates

• First Submitted: August 20, 2026
• First Posted: August 24, 2026
• Study Start: August 31, 2026
• Primary Completion (Estimated): April 30, 2027
• Study Completion (Estimated): April 30, 2027
• Last Updated: August 24, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will not share