Reviews/Targeted Therapy Prostate Cancer/Enzalutamide metastasis-free survival benefit in non-metastatic castration-resistant prostate cancer
Nmcrpc · PC-NMCRPC-01 · v2
The claim states a specific result from a single named trial, and the corpus carries that result directly. The PROSPER trial [6] randomised men with non-metastatic castration-resistant prostate cancer and a rapidly rising PSA to enzalutamide or placebo, and found that the time until cancer spread or death was much longer with enzalutamide. The exact numbers in the claim — the hazard ratio and the endpoint — appear word-for-word in that report. A later report from the same trial [1] shows these men also lived longer overall, which strengthens the case that the delay in spread reflects real patient benefit. The main caution noted by the panel is that all of this comes from one trial reported twice, so there is no independent study in the corpus confirming the exact figure.
The corpus confirms the claim at the source: [6] reports median metastasis-free survival of 36.6 versus 14.7 months with a hazard ratio of 0.29 (95% CI 0.24 to 0.35, P<0.001) in 1401 men with a PSA doubling time of 10 months or less (median 3.7 months). [1], the final analysis of the same trial, reports a concordant overall survival benefit (hazard ratio for death 0.73, 95% CI 0.61 to 0.89, P=0.001; median 67.0 vs 56.3 months), addressing the concern that the primary endpoint is only a surrogate. The corpus also contains the same metastasis-free-survival finding for other agents in this setting — darolutamide in [2] and [14] — but those are different drugs and do not bear on the enzalutamide-specific figure. [6] and [1] are the only enzalutamide-in-nmCRPC reports here. The contested point: The division is not over whether the result occurred but over how much a single trial's surrogate endpoint should carry: the HR 0.29 comes only from PROSPER [6], with no independent replication in the corpus, and is drawn from the primary metastasis-free-survival analysis rather than the later mature readout [1], which reports overall survival instead of an updated MFS figure.
All 15 papers behind this claim with their DOIs and what each does to it, the panel’s arbitration, the evidence gap map and the open research questions. Free, and sent to your inbox.
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One reviewer's only job is to attack the finding. The challenges below were weighed before the grade was set.
The evidence derives from a single trial (PROSPER, NCT02003924) reported across [6] and [1]; there is no independent replication of the HR 0.29 within the corpus.
MFS is a radiographic surrogate endpoint, not a hard patient outcome; however [1] reports a concordant OS benefit (HR for death 0.73) in the same trial, substantially mitigating the indirectness concern.
Where it remains uncertain. All evidence derives from one trial reported twice ([6], [1]), so there is no independent replication of HR 0.29 within the corpus and the figure is from the primary rather than the final analysis.
Aleatory
The hazard ratio carries a 95% confidence interval of 0.24 to 0.35 in [6], the irreducible statistical range around the point estimate.
Epistemic
Both [6] and [1] are the same trial (NCT02003924); the corpus contains no second enzalutamide nmCRPC trial confirming HR 0.29.
Inferential
MFS is a radiographic surrogate; its link to patient benefit rests on the concordant OS result (HR for death 0.73) in [1].
The load-bearing papers from a corpus of 15, each classified by what it does to the claim. Every DOI is taken from the corpus the claim was graded on.
Same-trial corroboration of the MFS improvement, with the final analysis additionally showing an overall survival benefit.
“Preliminary trial results showed that enzalutamide significantly improved metastasis-free survival among men who had nonmetastatic, castration-resistant prostate cancer and rapidly increasing prostate-specific antigen (PSA) levels while taking androgen-deprivation therapy.”
Panel auditInternal validity: high · scope of inference: Men with nonmetastatic castration-resistant prostate cancer and PSA doubling time ≤10 months; this abstract speaks to overall survival, not the MFS contrast.Key limitations: MFS result and HR 0.29 not reported in this abstract · endpoint reported is OS not MFS · MFS statement is background to prior analysis
Directly establishes the claimed MFS benefit and the exact HR of 0.29 in the PROSPER nmCRPC population.
“Among men with nonmetastatic, castration-resistant prostate cancer with a rapidly rising PSA level, enzalutamide treatment led to a clinically meaningful and significant 71% lower risk of metastasis or death than placebo.”
Panel auditInternal validity: high · scope of inference: Men with nonmetastatic castration-resistant prostate cancer and PSA doubling time ≤10 months continuing ADT.Key limitations: MFS defined by conventional imaging (pre-PSMA era) · OS immature at this analysis
2 of 15 papers shown. The full review lists all of them, with the panel’s arbitration →
Claims are graded at each quarterly release, and re-graded between releases only when a pivotal trial lands. Every change is a new version of the claim.
A large double-blind phase 3 RCT reports the exact endpoint, population and hazard ratio stated, with same-trial OS confirmation and no contradicting primary evidence.
Release 2026-q4 re-graded every claim from its corpus under protocol v0.19. An earlier release's grade is shown for the record; it came from an earlier protocol and is not a movement.
Assumptions that carry weight but are not themselves established.
The panel records the gap that would most move the claim, and the study that would close it.
Independent replication of the MFS effect. HR 0.29 is sourced solely from PROSPER ([6], [1]); no independent enzalutamide nmCRPC trial corroborates it in the corpus. The panel rates this the highest-importance open gap for the claim, and names the study design that would close it: A second randomised trial of enzalutamide versus placebo in nmCRPC with PSA doubling time 10 months or less, reporting MFS.
Open question: Is the MFS hazard ratio of 0.29 reproducible in an independent enzalutamide nmCRPC population? Why it is still open: Both corpus reports of this figure ([6], [1]) come from the same trial, so independence cannot be assessed from the corpus.
Priors is a sceptical first reader, not peer review, and not medical advice.
Release 2026-q4 · graded 26 Oct 2026 · protocol v0.19