Nearly half of all patients who undergo radical prostatectomy with curative intent will see their prostate cancer return — a stubborn clinical reality that surgery alone has failed to resolve for decades. The PROTEUS trial’s final analysis, presented as the opening plenary at ASCO 2026 and simultaneously published in the New England Journal of Medicine, puts a precise number on how much that reality can change: patients receiving perioperative apalutamide plus androgen deprivation therapy were nine times more likely to have little or no residual cancer at the time of surgery compared with hormone therapy alone — a pathologic complete response or minimal residual disease rate of 8.9% versus 1.0%.
The trial enrolled 2,109 patients with newly diagnosed high-risk localized or locally advanced prostate cancer. The design was perioperative — six months of apalutamide plus ADT before radical prostatectomy, then continued after. Both dual primary endpoints were met. The pathologic response difference is striking on its own, but the metastasis-free survival signal is what reshapes the long-term calculus: a statistically significant 20% reduction in the risk of metastasis or death (HR 0.80; 95% CI 0.67–0.96; p=0.02), with five-year MFS rates of 78.2% versus 73.5%. Time to subsequent therapy was pushed beyond six years in the apalutamide arm. After a median follow-up of nearly 62 months, neither endpoint showed signs of eroding.
What makes the PROTEUS data clinically consequential is the intervention window it targets. Standard practice has long reserved systemic intensification for later disease states — apalutamide itself carries FDA approvals in non-metastatic castration-resistant and metastatic castration-sensitive prostate cancer, settings where disease burden is already established. Applying an AR-pathway inhibitor perioperatively in localized disease — before micrometastatic spread becomes clinically detectable — represents a genuine shift in sequencing logic. The surgical specimen becomes a functional biomarker: a near-pathologic-complete-response rate nine times higher than the control arm is evidence that the tumor is being systematically destabilized before the prostatectomy even occurs.
The immediate regulatory question is whether J&J pursues a supplemental NDA for the perioperative setting and how quickly review proceeds given the NEJM publication and ASCO plenary designation. The specific marker to track: the pCR/MRD rate as a surrogate endpoint in the FDA review process — if regulators accept it as clinically meaningful in this context, it sets a template for how future neoadjuvant prostate cancer trials design and power their primary endpoints.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
