A Phase 1 interventional study of Relugolix and Enzalutamide in Androgen Deprivation Therapy and Locally Advanced Prostate Cancer, sponsored by University of Oklahoma. Recruiting at 1 site in United States. Open to male participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-03-05.
Sponsored by University of Oklahoma · Phase 1, Interventional, and Treatment
The goal of this clinical trial is to test how effective and safe it is to use a combination of two medications, relugolix and enzalutamide, in patients with advanced prostate cancer. We want to see if this combination can help improve the chances of curing the cancer and make the patients live longer without the cancer getting worse.
The main questions we want to answer in this study are:
Participants in this study will be asked to take relugolix and enzalutamide as part of their cancer treatment. They will also undergo Radiation Therapy or prostatectomy, which are standard treatments for this type of cancer.
This clinical trial aims to assess the effectiveness and safety of combining relugolix and enzalutamide as neoadjuvant and adjuvant androgen deprivation therapy (ADT) in patients diagnosed with high-risk locally advanced prostate cancer who are also candidates for definitive radiation therapy (RT) or surgical treatment. The objectives of this phase Ib clinical trial are to evaluate the efficacy, safety, and dynamic changes in biomarkers associated with this combination therapy. A combined total of up to 41 evaluable patients will participate in this study, with the initial safety lead-in cohorts involving a potential enrollment of 12 patients, followed by a dose expansion cohort that may include up to 29 subjects.
The combined treatment cycle spans 28 days, with patients receiving six months of neoadjuvant therapy followed by an additional 18 months in the adjuvant setting. Treatment duration may be shortened if unacceptable toxicity occurs or if a patient withdraws consent. Approximately 24 months of post-accrual follow-up are anticipated to adequately assess the efficacy and safety of the treatment.
Ultimately, the study aims to contribute valuable insights into the potential benefits of neoadjuvant and adjuvant hormonal therapy with relugolix plus enzalutamide in improving outcomes for patients facing high-risk locally advanced prostate cancer.
138 studies on the registry are indexed under Pathologic Complete Response; 57 are open to participants now.
This study's planned enrollment of 46 is below the median of 85 across 92 interventional studies indexed under Pathologic Complete Response.
Browse Pathologic Complete Response studies →University of Oklahoma is the lead sponsor of 432 studies on the registry; 100 are open to participants now.
Of its 42 completed or terminated interventional studies of FDA-regulated products, 16 (38%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Men with a diagnosis of adenocarcinoma of the prostate proven diagnosis with the following:
Have normal organ and bone marrow function measured at the screening visit including
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Absolute neutrophil count (ANC)
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A single-arm Phase Ib study explores the effectiveness and safety of neoadjuvant and adjuvant hormonal therapy combining relugolix and enzalutamide in high-risk locally advanced prostate cancer patients eligible for ADT followed by radiation therapy or surgery.
Drug: Relugolix and Enzalutamide
Drug pages: Relugolix · Enzalutamide
Dose level of Relugolix and Enzalutamide Safety Lead-in Cohort, 3-12 patient. Relugolix;120 mg, oral, once daily, with a loading dose of 360 mg on day 1, Enzalutamide; 120-160 mg, oral, once daily. Dose Expansion Cohort, up to 34 patients. Relugolix;120 mg, oral, once daily, with a loading dose of 360 mg on day 1, Enzalutamide; To be determined by safety lead-in cohort. One cycle = 3 months The dose limiting toxicity (DLT) period is the first 28 days Neoadjuvant ADT: 6 months; Relugolix: 120 mg orally, daily (with a 360 mg loading dose on day 1, Enzalutamide: 160 mg (or 120 mg) orally, daily Concurrent ADT during Radiation Therapy; Relugolix: 120 mg orally, daily (with a 360 mg loading dose on day 1, Enzalutamide: 160 mg (or 120 mg) orally, daily Maintenance ADT: Additional 18 months; Relugolix: 120 mg orally, daily (with a 360 mg loading dose on day 1, Enzalutamide: 160 mg (or 120 mg) orally, daily
Proportion of patient experiencing dose limiting toxicity (DLT) and tolerable dose of relugolix and enzalutamide combination
Proportion of patients will undergo evaluation for dose-limiting toxicity (DLT) to establish a tolerable dosage regimen for the combined use of relugolix and enzalutamide in individuals diagnosed with high-risk locally advanced prostate cancer. The assessment hinges on identifying DLTs associated with this treatment using 3-12 patients from the safety lead-in cohort and continuously monitoring treatment-related adverse events throughout the DLT observation period, which spans 24 months, encompassing neoadjuvant and adjuvant treatment phases.
Time frame: 2-3 years
Proportion of patients experiencing Pathologic Complete Response (pCR) and Minimal Residual Disease (MRD) in Neoadjuvant ADT with the combination of Relugolix and Enzalutamide
Proportion of patients achieving a pathologic response rate, defined as the combined Pathologic Complete Response (pCR) Rate and Minimal Residual Disease (MRD) rate (MRD, tumor ≤5 mm), serves as the primary endpoint for the dose expansion cohort. This assessment will be conducted using Simon's optimal 2-stage design, enabling a determination of whether there are an adequate number of patients with objective responses to proceed to the second stage of the study (at the interim analysis) or to consider the drug for further investigation in a Phase III study (at the study's conclusion).
Time frame: 4-6 years
Objective response rate (ORR) of neoadjuvant ADT of relugolix and enzalutamide
Assessing the objective response rate (ORR) in patients with high-risk locally advanced prostate cancer eligible for definitive radiation therapy (RT) or radical prostatectomy, following neoadjuvant ADT with relugolix and enzalutamide. ORR will be determined based on MRI imaging confirmation, defined as the percentage of patients achieving a complete response (CR) or partial response (PR) per RECIST v1.1 criteria.
Time frame: 4-6 years
Frequency and severity of adverse events of relugolix and enzalutamide
Assessment includes the rate and severity of treatment-related adverse events as per the NCI CTCAE v5 grading system.
Time frame: 4 years
Prostate specific antigen (PSA) response to the combination of relugolix and enzalutamide
Measurement of prostate-specific antigen (PSA) response, includes the rate and duration of a 50% reduction in PSA levels from baseline.
Time frame: 4 years
Diagnostic precision and constraints of biopsy in assessing positive margin rates and rates of pathologic downgrade.
Assessments involves diagnostic capabilities of biopsy-based analysis for prostatectomy, as reflected in the rates of positive margin in whole-mount pathology following intense neoadjuvant therapy and the pathologic downgrade compared to the initial T stage.
Time frame: 4-6 years
Progression-Free Survival (PFS) in Patients Receiving Neoadjuvant Relugolix and Enzalutamide
Assessment of Progression-Free Survival (PFS); defined as the interval from the initial dose to the earliest evaluation of progression according to RECIST v1.1 criteria, in patients undergoing neoadjuvant treatment with Relugolix and Enzalutamide, followed by radical local-regional Radiation Therapy (RT) or Radical Prostatectomy (RP) and subsequent adjuvant maintenance Androgen Deprivation Therapy (ADT).
Time frame: 4-6 years
Plan to share: No
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Studies of the drugs tested here: Relugolix · Enzalutamide
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