# AFFIRM

Source: https://onco.cc/trials/affirm/  
OnCo record `affirm` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Showed that a drug blocking the androgen receptor itself, rather than the hormones that feed it, adds nearly five months of life after chemotherapy has failed.

## Summary

AFFIRM randomised 1,199 men with castration-resistant prostate cancer after docetaxel 2:1 to enzalutamide 160 mg daily (800) or placebo (399), stratified by ECOG performance status and pain intensity. The trial was stopped at a planned interim analysis after 520 deaths.

Median overall survival was 18.4 months (95 percent confidence interval 17.3 to not yet reached) with enzalutamide against 13.6 months (11.3 to 15.8) with placebo, hazard ratio 0.63 (0.53 to 0.75, p<0.001). Every secondary endpoint favoured enzalutamide: PSA fall of 50 percent or more in 54 against 2 percent, soft-tissue response 29 against 4 percent, quality-of-life response 43 against 18 percent, time to PSA progression 8.3 against 3.0 months (hazard ratio 0.25), radiographic progression-free survival 8.3 against 2.9 months (0.40) and time to first skeletal-related event 16.7 against 13.3 months (0.69), all p<0.001.

Fatigue, diarrhoea and hot flushes were more common with enzalutamide. Seizures occurred in five men (0.6 percent), which is the toxicity that defines the drug's contraindications and the reason it is used cautiously in men with a seizure history or brain metastases.

In England NICE TA316 recommends enzalutamide within its marketing authorisation for metastatic hormone-relapsed prostate cancer that has progressed during or after docetaxel, with the patient access scheme discount, and explicitly states that use after abiraterone is not covered by that guidance.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-25
- Also known as: AFFIRM; MDV3100-03
- Registry id: NCT00974311
- Phase: 3
- Setting: Metastatic castration-resistant prostate cancer after docetaxel, stratified by ECOG performance status and pain intensity: enzalutamide 160 mg daily against placebo, randomised 2:1, with overall survival as the primary endpoint
- Sponsor: Medivation and Astellas Pharma Global Development
- Enrolled: 1199
- Result: Median overall survival 18.4 against 13.6 months (hazard ratio 0.63, 95 percent confidence interval 0.53 to 0.75) after docetaxel; PSA fall of 50 percent or more in 54 against 2 percent; seizures in 0.6 percent.
- Outcomes: Overall survival (median): Enzalutamide 160 mg daily 18.4 months vs Placebo 13.6 months, HR 0.63; Radiographic progression-free survival (median): Enzalutamide 160 mg daily 8.3 months vs Placebo 2.9 months, HR 0.4; PSA decline of 50 percent or more: Enzalutamide 160 mg daily 54% vs Placebo 2%
- Replication: COU-AA-301 found the same in the same setting with abiraterone (14.8 against 10.9 months); PREVAIL moved enzalutamide before chemotherapy.

## Sources

- ClinicalTrials.gov NCT00974311: https://clinicaltrials.gov/study/NCT00974311
- AFFIRM (New England Journal of Medicine 2012): https://doi.org/10.1056/NEJMoa1207506
- NICE TA316: enzalutamide for metastatic hormone-relapsed prostate cancer previously treated with a docetaxel-containing regimen: https://www.nice.org.uk/guidance/ta316

## Connected records

- cancers: [Metastatic castration-resistant prostate cancer](https://onco.cc/cancers/prostate-mcrpc/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- technologies: [Androgen deprivation & AR pathway inhibitors](https://onco.cc/technologies/androgen-deprivation/)
- targets: [Androgen receptor](https://onco.cc/targets/androgen-receptor/)
- drugs: [Enzalutamide](https://onco.cc/drugs/enzalutamide/)
- companies: [Astellas](https://onco.cc/companies/astellas/), [Pfizer (incl. Seagen)](https://onco.cc/companies/pfizer/)
- terms: [Androgen receptor pathway inhibitor (ARPI)](https://onco.cc/terms/arpi/), [Castration-resistant prostate cancer (CRPC)](https://onco.cc/terms/castration-resistance/), [PSA50 / PSA90 response](https://onco.cc/terms/psa50/), [Quality of life and patient-reported outcomes (QoL, PRO)](https://onco.cc/terms/qol-pro/), [What follows what in castration-resistant prostate cancer](https://onco.cc/terms/prostate-crpc-sequencing/)
- trials: [ARMOR3-SV](https://onco.cc/trials/armor3-sv/), [CARD](https://onco.cc/trials/card/), [COU-AA-301](https://onco.cc/trials/cou-aa-301/), [PREVAIL](https://onco.cc/trials/prevail/)

---
JSON: https://onco.cc/api/v1/entities/affirm.json