The proposed trial is a single arm, two stage trial looking for an efficacy signal in the neoadjuvant setting in patients with PTEN-null tumors. The active therapy is a combination of androgen deprivation therapy, darolutamide, and ipatasertib. Patients will be treated for 6 months prior to prostatectomy, since previous studies have shown that pCR+MRD rate is higher with 6 months of ADT + abiraterone (24%) than 3 months (4%) (Taplan ME et al. J Clin Oncol. 2014;32(33):3705-15). Since the combination has not been evaluated before, a lead-in cohort in patients with castration resistant prostate cancer will be performed to evaluate safety and drug-drug interaction.~The lead-in cohort will enroll 6 patients to assess the safety of ipatasertib and darolutamide. Ipatasertib has already been evaluated in combination with the AR pathway inhibitors abiraterone and enzalutamide, where 400 mg was found to be safe. Therefore patients will receive the expected final dose of darolutamide 600 mg BID and ipatasertib 400 mg daily. Toxicities will be monitored for 28 days, and blood samples will be drawn for pharmacokinetic (PK) studies. If one or fewer patients experience a DLT the trial will advance to the neoadjuvant setting. If two or more patients experience a DLT at 400 mg, the dose will be reduced for already enrolled patients and another 6 patients will be enrolled to evaluate darolutamide 600 mg BID and ipatasertib 200 mg daily.~PK evaluations will continue for a total of 6 months. Enrollment in the neoadjuvant cohort can proceed before PK studies are complete.~Patients will have response evaluated at 12 weeks, including PSA response and radiographic response per modified PCWG3. If there is progression on bone scan alone, patients should have confirmatory bone scan in at least 6 weeks later. Patients will continue on therapy until the time of progression.
This multicenter Phase I/II trial consists of two stages: a phase I stage in patients with castration resistant prostate cancer in which the recommended phase II dose will be determined for ipatasertib administered in combination with darolutamide; and a phase II neoadjuvant stage in which patients with high risk prostate cancer and loss of PI3K pathway activation in the tumor tissue planning on undergoing prostatectomy receive ADT, darolutamide, and ipatasertib for 24 weeks prior to planned surgery.