Prostate CancerPhase 1NCT07783282
A Study to Learn How Enzalutamide, Apalutamide and Bicalutamide Affect the Way Fezolinetant is Processed in Men With Prostate Cancer
A Phase 1 study testing fezolinetant, enzalutamide and apalutamide in people with Prostate Cancer, run by Astellas Pharma Global Development, Inc. at 1 site in Bulgaria.
Trial 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. Read more about this study
- Who is it for?
- Ages 50 to 75 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Prostate Cancer
- What is being tested?
- fezolinetant, enzalutamide and apalutamide
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 56 participants
- Where
- 1 siteBulgaria
- Study dates
- 25 Sep 2026to 30 Apr 2027
- Phase
- Phase 1
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 50 to 75 years
- Men only
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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.
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- 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.
Who cannot join
- 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.
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- 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.
- Participant has smoked, used tobacco-containing products or nicotine or nicotine-containing products (e.g., electronic vapes) within 6 months prior to screening or the participant tests positive for cotinine at screening or day -1.
- Participant has had significant blood loss, donated >/=1 unit (450 mL) of whole blood or donated plasma within 7 days prior to day -1 and/or received a transfusion of any blood or blood products within 60 days.
- Participant has a history of consuming > 10 units of alcoholic beverages per week within 3 months prior to screening (note: 1 unit = 350 mL of beer, 150 mL of wine, 45 mL of spirits/hard liquor).
- Participant has used any drugs of abuse (e.g., amphetamines, barbiturates, benzodiazepines, cocaine, opiates and cannabinoids) within 3 months prior to day -1.
- Participant has a history of malignancy within 2 years before screening except for prostate cancer. Exception: squamous and basal cell carcinoma of the skin, or other malignancy that is considered cured with minimal risk of recurrence are allowed, upon agreement by the sponsor's medical monitor.
- Participant has had surgery or chemotherapy treatment, immunotherapy or other targeted therapy for prostate cancer within the last 3 months prior to signing informed consent. Radiotherapy is allowed.
- Participant plans to initiate treatment with chemotherapy during the study.
- Participant has a medical condition or chronic disease (including history of neurological [including cognitive], hepatic, renal, cardiovascular, gastrointestinal, pulmonary [e.g., moderate asthma]) or malignancy that could confound interpretation of the study outcome.
- Participant has known metastases in the liver or any hepatic disorder that could affect drug metabolism deemed clinically significant.
- Participant uses a prohibited therapy or is not willing to wash out such drugs.
- Participant has used any inducer of metabolism (e.g., barbiturates and rifampin) within 28 days prior to day -1.
- Participant uses any concomitant medication that is an inhibitor of CYP1A2, CYP2C9 or CYP2C19 within 7 days prior to day -1.
- Participant has any history or evidence of any clinically significant cardiovascular, gastrointestinal, endocrinologic, hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, neurologic, dermatologic, psychiatric, renal and/or other major disease or malignancy.
- Participant has used any prescribed or nonprescribed drugs (including vitamins and natural and herbal remedies, e.g., St. John's Wort) in the 28 days prior to study intervention administration (i.e., 45 mg fezolinetant) on day 1, except for occasional use of acetaminophen or paracetamol (up to 2 g/day) and topical dermatological products (including corticosteroid products).
- Participant has a mean pulse < 40 or > 90 bpm; mean systolic blood pressure (SBP) > 160 mmHg; mean diastolic blood pressure (DBP) > 100 mmHg (measurements taken in triplicate after participant has been resting in the supine position for at least 5 minutes; pulse will be measured automatically) on day -1. If the mean blood pressure exceeds the limits above, 1 additional triplicate may be taken.
- Participant has a mean corrected QT interval by Fridericia's correction formula (QTcF) of > 450 msec on day -1.
- Participant is an employee of Astellas, the study-related contract research organization (CROs) or the clinical unit.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Bulgaria1 site, 1 recruiting
- Recruiting
Site BG35907
Plovdiv, Plovdiv Province
About this study
Official title: A Phase 1 Open-label Study to Evaluate the Effect of Enzalutamide, Apalutamide and Bicalutamide on the Pharmacokinetics of Fezolinetant in Male Participants With Prostate Cancer
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.
Read more
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
- Being tested
- fezolinetant, enzalutamide, apalutamide, bicalutamide, GnRH agonist/antagonist
- Keywords
- Prostate Cancer, ESN364, fezolinetant, VEOZAH™, Pharmacokinetics, Healthy Volunteer
- Medical subject headings
- Prostatic Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
fezolinetantDrug
Also called ESN364, VEOZAH™
oral
enzalutamideDrug
Also called MDV3100, Xtandi™
oral
apalutamideDrug
oral
bicalutamideDrug
oral
GnRH agonist/antagonistDrug
Per local product label
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: 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. Receives: 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. Receives: Drug: fezolinetant |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pharmacokinetics (PK) of Fezolinetant in plasma: Maximum Concentration (Cmax)
Cmax will be recorded from the PK plasma samples collected.
Measured: 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.
Measured: Up to Day 3
Secondary outcomes (7)
Number of participants with Adverse Events (AEs)
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom or disease (new or exacerbated) temporally associated with the use of study intervention. This includes events related to the comparator, if applicable, and events related to the (study) procedures.
Measured: Up to Day 12
Number of participants with laboratory value abnormalities and/or adverse events (AEs)
Number of participants with potentially clinically significant laboratory values.
Measured: Up to Day 12
Number of participants with vital sign abnormalities and/or adverse events (AEs)
Number of participants with potentially clinically significant vital sign values.
Measured: Up to Day 12
Number of participants with electrocardiogram (ECG) abnormalities and/or Adverse Events (AEs)
Number of participants with potentially clinically significant ECG values.
Measured: Up to Day 12
PK of metabolite ES259564 in plasma: Cmax
Cmax will be recorded from the PK plasma samples collected.
Measured: Up to Day 3
PK of metabolite ES259564 in plasma: AUCinf
AUCinf will be recorded from the PK plasma samples collected.
Measured: Up to Day 3
Metabolite ES259564 to parent ratio for AUCinf
Metabolite ES259564 AUCinf and Fezolinetant AUCinf will be recorded from the PK plasma samples collected.
Measured: Up to Day 3
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Aug 2026
- Study start25 Sep 2026
- Primary completion30 Apr 2027 (estimated)
- Study completion30 Apr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Prostate CancerStudies of the same condition, open and under way.
- More trials run by Astellas Pharma Global Development, Inc.The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 56 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Astellas Pharma Global Development, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Monitor, Study director, Astellas Pharma Global Development, Inc.
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07783282
- Sponsor's protocol ID
- 2693-CL-2101
- Other IDs
- 2024-520286-31
- Status last verified
- Oct 2026
- First submitted
- 20 Aug 2026
- Last updated
- 16 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Access to anonymized individual participant level data will not be provided for this trial. Further details on Astellas' data sharing policy can be found at https://www.clinicaltrials.astellas.com/transparency/.