Addition of Darolutamide to First Line Treatment of Metastatic Castration-Resistant Prostate Cancer (mCRPC): a Randomized Open Label Phase II Trial
Despite improvements in treatment, metastatic prostate cancer remains incurable, especially in the case of pretreated metastatic castration-resistant disease (mCRPC), where treatment options are limited, leading to an unmet need. The paradigm shift in the treatment of metastatic hormone-sensitive prostate cancer (mHSPC) has affected the treatment landscape for mCRPC patients. Many have already received androgen deprivation therapy (ADT) and androgen receptor pathway inhibitors (ARPI), making first-line mCRPC treatment challenging. The Swiss Group for Clinical Cancer Research (SAKK) has shown in previous studies that maintenance treatment with an ARPI, such as darolutamide, can improve radiographic progression-free survival (rPFS) in pretreated mCRPC patients. In the SAKK 08/16 trial, darolutamide maintenance was found to prolong PFS compared to placebo, especially in patients who responded well to prior ARPI treatment. Based on these findings, the hypothesis is that continued AR-pathway blockade with darolutamide, initiated in patients progressing from mHSPC to mCRPC on ARPI treatment, can improve outcomes when added to standard first-line mCRPC therapy and continued as maintenance. The proposed study aims to evaluate the efficacy of darolutamide, combined with physician-choice standard of care (including taxane chemotherapy, olaparib, radium 223, or LuPSMA), followed by maintenance therapy, on rPFS for patients in the first-line setting of mCRPC.
• Written informed consent according to Swiss law and ICH GCP E6(R2) regulations before registration and prior to any trial specific procedures
• Histologically or cytologically confirmed diagnosis of adenocarcinoma of the prostate
• Castration resistance: tumor progression after orchiectomy or during treatment with GnRH analogues (agonists or antagonists).
• Non-surgically castrated patient agrees on ongoing use of GnRH analogues (agonists or antagonists) during the trial
• Metastatic disease, documented by imaging according to PCWG3 criteria
• Measurable disease or bone lesions that are evaluable according to PCWG3 criteria
• A minimum of 12 months on ADT+ARPI therapy (calculated from ADT initiation) within mHSPC setting, showing an at least 50% PSA response or partial remission according to RECIST v1.1. ARPI change within mHSPC is only allowed for intolerance.
• Progressive disease according to modified PCWG3 before registration is defined as (at least 2 out of 3):
‣ PSA progression ≥ 25% above nadir (2 consecutive rises at least 3 weeks apart)
⁃ New metastatic lesion on imaging (at least two or more new bone lesions on bone scan or one new non-bone lesion or progression on PSMA-PET/CT according to PROMISE V2 criteria
⁃ Clinical progression
• Patients with a previously treated malignancy are eligible, when the risk of the prior malignancy interfering with either safety or efficacy endpoints is very low
• Age ≥ 18 years
• WHO performance status 0-2
• Adequate bone marrow function: absolute neutrophil count ≥ 1.0 x 109/L, platelet count ≥ 100 x 109/L, hemoglobin ≥ 90 g/L.
• Adequate hepatic function: total bilirubin ≤ 1.5 x ULN (except for patients with Gilbert's disease ≤ 3.0 x ULN), ALT and AST ≤ 2.5 x ULN, or ≤ 5 x ULN under the assumption that abnormal values are a result of cancer
• Adequate renal function: estimated glomerular filtration rate (eGFR) \> 30 mL/min/1.73 m2 (according to CKD-EPI formula)
• Men agree not to donate sperm or to father a child during trial treatment and until 3 months after the last dose of trial treatment
• Patients are able and willing to swallow darolutamide as whole tablet.