Phase IB Trial of Relugolix and Enzalutamide as Neoadjuvant/ Adjuvant to Local-regional Treatment in Patients With High-risk Locally Advanced Prostate CAncer (RENAPCA)
Summary
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: * Can using relugolix and enzalutamide together help increase the chances of curing high-risk advanced prostate cancer? * Does this combination treatment help patients live longer without their cancer getting worse? 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.
Detailed description
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.
Arms & interventions
- DrugRelugolix and 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
Outcome measures
Primary
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
Secondary
Objective response rate (ORR) of neoadjuvant ADT of relugolix and enzalutamide
Time frame: 4-6 years
Frequency and severity of adverse events of relugolix and enzalutamide
Time frame: 4 years
Prostate specific antigen (PSA) response to the combination of relugolix and enzalutamide
Time frame: 4 years
Diagnostic precision and constraints of biopsy in assessing positive margin rates and rates of pathologic downgrade.
Time frame: 4-6 years
Progression-Free Survival (PFS) in Patients Receiving Neoadjuvant Relugolix and Enzalutamide
Time frame: 4-6 years
Eligibility criteria
Study locations (1)
Stephenson Cancer Center at OU Health, University of Oklahoma Health Sciences Center (SCC-OUHSC)
Oklahoma City, Oklahoma, 73104
References
- Loper M, Qadar A, Vesely SK, Gunter T, Ayanambakkam A, Wen Y, Cookson M, Stratton K. Neoadjuvant/adjuvant relugolix and enzalutamide for the treatment of high-risk locally advanced prostate cancer: study protocol of the RENAPCA phase Ib trial. BMJ Open. 2026 Apr 24;16(4):e112623. doi: 10.1136/bmjopen-2025-112623.(PubMed)