RESUMO
BACKGROUND: Enzalutamide significantly prolonged the survival of men with metastatic castration-resistant prostate cancer (PCa) after docetaxel in the randomised, phase 3, double-blind, placebo-controlled, multinational Patients with Progressive Castration-Resistant Prostate Cancer Previously Treated with Docetaxel-Based Chemotherapy (AFFIRM) trial (NCT00974311). Prostate-specific antigen (PSA) is commonly used as a marker of PCa disease burden, and the relationship of baseline PSA level to consequent treatment effect is of clinical interest. OBJECTIVE: Exploratory analysis to evaluate any differences in patient characteristics and efficacy outcomes by baseline PSA level in the AFFIRM trial. DESIGN, SETTING, AND PARTICIPANTS: Post hoc subanalysis of all randomised patients (n=1199) from the AFFIRM trial. INTERVENTION: Participants were randomly assigned in a two-to-one ratio to receive oral enzalutamide 160 mg/d or placebo. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The major clinical efficacy end points were overall survival (OS), radiographic progression-free survival (rPFS), and time to PSA progression (TTPP) versus placebo; baseline characteristics, treatment duration, and subsequent antineoplastic therapy were compared by baseline PSA quartile. RESULTS AND LIMITATIONS: Baseline PSA quartiles corresponded to the following PSA groups: <40 ng/ml (n=299), 40 to <111 ng/ml (n=300), 111 to <406 ng/ml (n=300), and ≥406 ng/ml (n=300). Enzalutamide consistently improved OS, rPFS, and TTPP compared with placebo across all subgroups, regardless of baseline PSA level. Hazard ratios for improvements in OS were 0.55 (95% confidence interval [CI], 0.36-0.85), 0.69 (95% CI, 0.47-1.02), 0.73 (95% CI, 0.53-1.01), and 0.53 (95% CI, 0.39-0.73) for PSA groups 1-4, respectively. The post hoc design of this analysis was not statistically powered to assess the relationship between baseline PSA and clinical efficacy outcomes. CONCLUSIONS: This post hoc analysis of the AFFIRM trial demonstrates consistent benefits in OS, rPFS, and TTPP with enzalutamide regardless of baseline disease severity, as assessed by PSA. PATIENT SUMMARY: Exploratory post hoc analysis of the AFFIRM trial showed that enzalutamide improves overall survival, radiographic progression-free survival, and time to prostate-specific antigen progression compared with placebo regardless of baseline disease severity, as assessed by prostate-specific antigen. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT00974311.
Assuntos
Antineoplásicos/uso terapêutico , Calicreínas/sangue , Feniltioidantoína/análogos & derivados , Antígeno Prostático Específico/sangue , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Idoso , Austrália , Benzamidas , Progressão da Doença , Intervalo Livre de Doença , Método Duplo-Cego , Europa (Continente) , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Nitrilas , América do Norte , Feniltioidantoína/uso terapêutico , Modelos de Riscos Proporcionais , Neoplasias de Próstata Resistentes à Castração/sangue , Neoplasias de Próstata Resistentes à Castração/mortalidade , Neoplasias de Próstata Resistentes à Castração/patologia , Fatores de Risco , África do Sul , América do Sul , Fatores de Tempo , Resultado do TratamentoRESUMO
BACKGROUND: Docetaxel plus prednisone is standard first-line chemotherapy for men with metastatic castrate-resistant prostate cancer. Aflibercept is a recombinant human fusion protein that binds A and B isoforms of VEGF and placental growth factor, thereby inhibiting angiogenesis. We assessed whether the addition of aflibercept to docetaxel and prednisone would improve overall survival in men with metastatic castrate-resistant prostate cancer compared with the addition of placebo to docetaxel and prednisone. METHODS: VENICE was a phase 3, multicentre, randomised double-blind placebo-controlled parallel group study done in 31 countries (187 sites). Men with metastatic castrate-resistant prostate cancer, adequate organ function, and no prior chemotherapy were treated with docetaxel (75 mg/m(2) intravenously every 3 weeks) and oral prednisone (5 mg twice daily) and randomly allocated (1:1) to receive aflibercept (6 mg/kg) or placebo, intravenously, every 3 weeks. Treatment allocation was done centrally via an interactive voice response system, using a computer-generated sequence with a permuted-block size of four and stratified according Eastern Co-operative Group performance status (0-1 vs 2). Patients, investigators, and other individuals responsible for study conduct and data analysis were masked to treatment assignment. Aflibercept or placebo vials were supplied in identical boxes. The primary endpoint was overall survival using intention-to-treat analysis. This is the primary analysis of the completed trial. The study is registered with ClinicalTrials.gov, number NCT00519285 FINDINGS: Between Aug 17, 2007, and Feb 11, 2010, 1224 men were randomly allocated to treatment: 612 to each group. At final analysis, median follow-up was 35 months (IQR 29-41) and 873 men had died. Median overall survival was 22·1 months (95·6% CI 20·3-24·1) in the aflibercept group and 21·2 months (19·6-23·8) in the placebo group (stratified hazard ratio 0·94, 95·6% CI 0·82-1·08; p=0·38). We recorded a higher incidence of grade 3-4 gastrointestinal disorders (182 [30%] vs 48 [8·0%]), haemorrhagic events (32 [5·2%] vs ten [1·7%]), hypertension (81 [13%] vs 20 [3·3%]), fatigue (97 [16%] vs 46 [7·7%]), infections (123 [20%] vs 60 [10%]) and treatment-related fatal adverse events (21 [3·4%] vs nine [1·5%]) in the aflibercept group than in the placebo group. INTERPRETATION: Aflibercept in combination with docetaxel and prednisone given as first-line chemotherapy for men with metastatic castrate-resistant prostate cancer resulted in no improvement in overall survival and added toxicity compared with placebo. Docetaxel plus prednisone remains the standard treatment for such men who need first-line chemotherapy. FUNDING: Sanofi and Regeneron Pharmaceuticals Inc.