Metacure: Multi-arm multimodality therapy for very high risk localized and low volume metastatic prostatic adenocarcinoma.

Abstract

TPS349 Background: Therapeutic advances in the management of metastatic castration-resistant prostate cancer (mCRPC) have not been matched in non-castrate states. A key obstacle is the traditional paradigm in which therapies with significant benefit in mCRPC are then studied in patients (pts) with localized, rising PSA or early metastatic disease using time-to-event (TTE) outcomes (e.g. biochemical recurrence, radiographic progression or death). These trials are costly, lengthy and often give inconclusive results that do not change practice nor provide a methodology to rank regimens based on efficacy. A new strategy is needed that gives a rapid efficacy readout and prioritizes approaches for large-scale testing. Methods: Metacure is a multi-arm, multi-stage randomized Phase 2 trial in which novel systemic therapies are studied in the context of a multimodality approach, which includes radical prostatectomy + pelvic and retroperitoneal lymph node dissection, if applicable, stereotactic radiotherapy (RT) to osseous metastases, and an option for adjuvant RT based on risk factors. The arms include combinations of ADT + apalutamide +/- abiraterone acetate and prednisone. Non-castrate prostate cancer pts with high probability of relapse or death from disease ranging from very high risk localized to low-volume metastatic disease are eligible. The primary endpoint is pathologic complete response and minimal residual disease. The secondary endpoint is undetectable PSA with non-castrate levels of testosterone. Both are binary endpoints that circumvent interpretations of the clinical relevance of TTE outcomes, providing a read-out of success or failure in a shorter time frame with fewer pts. The uniform entry criteria and continuous randomization enables ranking and prioritization of the strategies evaluated for further development in large-scale trials so that only the most effective ones move forward. This multicenter trial is managed by the Prostate Cancer Clinical Trials Consortium, funded by Janssen and is currently open and actively accruing. Future plans include opening a cohort of pts with aggressive non-castrate disease harboring DNA damage repair alterations. Clinical trial information: NCT03436654.