Enzalutamide,
does it really help with Added to ADT to prolong overall survival in high-risk nonmetastatic castration-resistant prostate cancer?
research showsEnzalutamide is rated B with 72 points: adding it to androgen-deprivation therapy (ADT) prolonged overall survival in high-risk nonmetastatic castration-resistant prostate cancer, but the citations are repeated reports of a single trial and no replication by different investigators and funders has been confirmed, so the axis-2 R1 ceiling of B applies. Among 1,401 participants in the phase 3 PROSPER trial, the risk of death was 27% lower than with placebo plus ADT (HR 0.73), and median overall survival was 67.0 versus 56.3 months. The same randomized trial prolonged metastasis-free survival from 14.7 to 36.6 months. Fatigue, hypertension, falls, and rare seizures are separate safety concerns.
ads claimMarketing may broaden the result to prostate cancer in general, but the demonstrated setting is add-on treatment to ADT in high-risk nmCRPC with rapidly rising PSA.
Useful facts when choosing a product
- Enzalutamide is an oral prescription androgen-receptor inhibitor; ADT is continued to maintain castrate testosterone in this setting.
- The PROSPER dose was 160 mg once daily, while actual prescribing must follow labeling and account for concomitant drugs, hepatic status, and tolerability.
- Fatigue, hypertension, falls, and fractures can occur, with rare seizures and posterior reversible encephalopathy syndrome.
- Its strong enzyme-inducing effects can lower concentrations of many concomitant medicines, so interaction review is necessary.
What the research actually shows
Hussain and colleagues reported that enzalutamide plus ADT extended metastasis-free survival by 21.9 months in the primary PROSPER analysis. The final analysis by Sternberg and colleagues confirmed overall survival HR 0.73 despite subsequent life-prolonging therapies and use of enzalutamide in the placebo group. Pfizer and Astellas funded the study, but the international multicenter double-blind randomized design, large sample, and mortality endpoint provide strong evidence.
Why this is classified as B (72)
PROSPER showed overall survival HR 0.73 and a 10.7-month median difference in a large double-blind placebo-controlled phase 3 trial, with consistent metastasis-free survival improvement. However, only one trial is cited (repeated reports of the same trial) and replication by different investigators and funders has not been confirmed, so the axis-2 R1 ceiling gives B with 72 points. Despite manufacturer funding, the axis-3 ceiling is not applied under the large hard-endpoint prescription-drug RCT exception.
Counterpoint. Absolute benefit depends on baseline risk and long follow-up in high-risk nmCRPC, and treatment decisions must weigh toxicity and interactions.
Rejudgment record. New verdict — Direct large phase 3 evidence from the ingredient-specific PROSPER comparison of enzalutamide plus ADT versus placebo plus ADT, with significant improvements in overall and metastasis-free survival; both citations are repeated reports of the same trial and no replication by different investigators and funders exists, so the axis-2 R1 ceiling of B applies (manufacturer funding does not trigger the axis-3 ceiling under the large hard-endpoint prescription-drug RCT exception)
| Endpoint | H | Hard endpoint - actual events such as death |
| Replication | R1 | Single confirmatory trial |
| Independence | I0 | Evidence comes only from manufacturer studies |
| Effect size | E+ | Meets the clinically important threshold |
The scoring table and the verdict agree (B).
Sub-claim grades by effect
This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.
| Effect (sub-claim) | Grade | Basis |
|---|---|---|
| Prolonged overall survival | A | HR 0.73 versus placebo plus ADT, with medians of 67.0 and 56.3 months. |
| Prolonged metastasis-free survival | A | 36.6 versus 14.7 months, HR 0.29. |
Cross-check — Codex and Claude
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Hussain M et al. PROSPER 2018 | International multicenter randomized double-blind placebo-controlled phase 3 trial | 1,401 | Pfizer and Astellas Pharma | Metastasis-free survival | 36.6 versus 14.7 months, HR 0.29 (95% CI 0.24 to 0.35). | Key primary analysis |
| Sternberg CN et al. PROSPER final OS 2020 | Prespecified final overall-survival analysis of the same randomized trial | 466 | Pfizer and Astellas Pharma | Overall survival | 67.0 versus 56.3 months, HR 0.73 (95% CI 0.61 to 0.89; P=0.001). | Grade-determining hard endpoint |
Receipt — 2 References
All 2 cited sources were verified for existence at the original page (as of 2026-08-11).
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-11 · Corrections: 1
Correction log — 1
Corrections applied to this verdict, in chronological order. Changes are logged, not erased.
- 2026-08-11 · Grade correction for unmet independent-replication requirement — Both cited papers were repeated reports of the same PROSPER trial (NCT02003924) in the same population. Chamgap's A requires axis-2 R2 (multiple RCTs by different investigators and funders); the only separately enrolled trial, STRIVE, was a phase 2 with mixed enrollment and a PFS endpoint funded by the same developer (Medivation/Astellas), so it is not independent replication of overall survival in high-risk nmCRPC. Axis 2 is R1, capping the grade at B. Axes were recorded as B·H·R1·I0·E+·B1 (axis-3 ceiling not applied under the large hard-endpoint prescription-drug RCT exception) and 72 points were assigned. The effect itself (overall survival HR 0.73, 67.0 versus 56.3 months; metastasis-free survival HR 0.29) is not disputed. Confirmed in the 2026-08-11 internal audit (workflow verification plus concordant Codex cross-check). (grade A→B)
Cite this verdict
[Chamgap] Enzalutamide x prolonged overall survival in high-risk nonmetastatic castration-resistant prostate cancer — Evidence Grade B·72. 2 cited sources checked. Source: https://chamgap.com/en/verdicts/mens/enzalutamide-nonmetastatic-castration-resistant-prostate-cancer-overall-survival/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
What this document does and does not do
Chamgap is an information source. It reports what research has and has not confirmed; it does not tell readers what to take or buy. That decision belongs to readers and, when needed, medical or legal professionals. This verdict reflects literature available up to the search date and may change as new research appears. Nothing here is medical advice.