Clinical efficacy of apalutamide in Asian patients with metastatic castration-sensitive prostate cancer: Bayesian reanalysis of the TITAN trial.

BACKGROUND

The phase 3 TITAN trial revealed that apalutamide plus androgen deprivation therapy (ADT) has significantly improved outcomes in patients with metastatic castration-sensitive prostate cancer (mCSPC). However, the generalizability of these results to Asian and Japanese populations remains unclear. Bayesian methods provide a probabilistic framework offering more clinically meaningful estimates of benefit in such subpopulations.

METHODS

We conducted a Bayesian post hoc analysis using reconstructed individual patient data from the published Asian (n = 221) and Japanese (n = 51) TITAN trial subpopulations. Bayesian Cox proportional hazards models were fitted under four prespecified priors representing different skepticism levels. Posterior median hazard ratios (HRs), 95% credible intervals (CrIs), and probabilities of any benefit (Pr[HR < 1.0]) or substantial benefit (Pr[HR < 0.8]) were calculated.

RESULTS

The posterior median HR under the neutral prior for overall survival in the Asian cohort was 0.71 (95% CrI 0.44-1.14), with Pr[HR < 1.0] = 92% and Pr[HR < 0.8] = 69%. Probabilities exceeded 95% under more informative priors. The Japanese cohort demonstrated more pronounced effects (neutral prior HR: 0.55, 95% CrI: 0.22-1.35) with ≥90% probability of benefit across all priors. Posterior median HRs for TTmCRPC were 0.32-0.35 across priors, with ~100% probability of treatment benefit in both cohorts.

CONCLUSION

This analysis provides strengthened evidence that apalutamide plus ADT offers meaningful clinical benefit for Asian patients with mCSPC. Moreover, our findings support more informed and individualized clinical decision-making, helping clinicians communicate expected outcomes more clearly during shared decision-making.