CHAMGAP
APPROVEDReviewed and approved by the Chamgap Editorial Team (2026-07-23). The draft was written by AI, the existence of all 2 cited sources was verified at the original page, and the verdict passed blind grading and adversarial audit. Methodology v0.6.
Verdict No. 1391 · Search date 2026-07-23 · Methodology v0.6

Enzalutamide,
does it really help with Added to ADT to prolong overall survival in high-risk nonmetastatic castration-resistant prostate cancer?

30-Second Summary
A
Evidence Grade A · 92 · Safety unknown
Adding enzalutamide to ADT prolongs overall survival in high-risk nonmetastatic castration-resistant prostate cancer
What the
research shows
Enzalutamide is rated A because adding it to androgen-deprivation therapy (ADT) prolonged overall survival in high-risk nonmetastatic castration-resistant prostate cancer. 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.
What the
ads claim
Marketing 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.
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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.
Gap Measurement · Verdict 1391 · A 92
What advertising claims
What independent, higher-quality research supports
△ GAP
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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.

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Why this is classified as A (92)

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. The ingredient-specific randomized hard endpoint supports A with 92 points.

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

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)GradeBasis
Prolonged overall survivalAHR 0.73 versus placebo plus ADT, with medians of 67.0 and 56.3 months.
Prolonged metastasis-free survivalA36.6 versus 14.7 months, HR 0.29.

Cross-check — Codex and Claude

This verdict was drafted by Codex through literature review and source-existence checks, cross-checked through blind grading and adversarial audit, and settled by reapplying the methodology boundary rules. Cases with split grades were resolved through rejudgment.
03

Evidence Table

StudyDesignSampleFundingEndpointResultWeight
Hussain M et al. PROSPER 2018International multicenter randomized double-blind placebo-controlled phase 3 trial1,401Pfizer and Astellas PharmaMetastasis-free survival36.6 versus 14.7 months, HR 0.29 (95% CI 0.24 to 0.35).Key primary analysis
Sternberg CN et al. PROSPER final OS 2020Prespecified final overall-survival analysis of the same randomized trial466Pfizer and Astellas PharmaOverall survival67.0 versus 56.3 months, HR 0.73 (95% CI 0.61 to 0.89; P=0.001).Grade-determining hard endpoint
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Receipt — 2 References

All 2 cited sources were verified for existence at the original page (as of 2026-07-23).

Hussain M, Fizazi K, Saad F, et al. Enzalutamide in Men with Nonmetastatic, Castration-Resistant Prostate Cancer. N Engl J Med. 2018;378(26):2465-2474. PMID: 29949494. DOI: 10.1056/NEJMoa1800536.
checked
Sternberg CN, Fizazi K, Saad F, et al. Enzalutamide and Survival in Nonmetastatic, Castration-Resistant Prostate Cancer. N Engl J Med. 2020;382(23):2197-2206. PMID: 32469184. DOI: 10.1056/NEJMoa2003892.
checked
Draft and rewrite: Codex (AI) · Verification: Codex blind grading and adversarial audit · Final adjudication: Claude
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-07-23 · Corrections: none

Cite this verdict

Enzalutamide x prolonged overall survival in high-risk nonmetastatic castration-resistant prostate cancer Evidence Grade A card
[Chamgap] Enzalutamide x prolonged overall survival in high-risk nonmetastatic castration-resistant prostate cancer — Evidence Grade A·92. 2 cited sources checked. Source: https://chamgap.com/en/verdicts/mens/enzalutamide-nonmetastatic-castration-resistant-prostate-cancer-overall-survival/ · CC BY 4.0

CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.

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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.