Androgen deprivation therapy with apalutamide in the treatment of metastatic castration-sensitive prostate cancer: the systematic review of its effectiveness and applicability for Asian men in the targeted investigational treatment analysis of novel anti-androgen (TITAN) trial.

BACKGROUND

The TITAN trial established survival benefits of adding apalutamide to androgen deprivation therapy (ADT) in metastatic castration‑sensitive prostate cancer (mCSPC). Whether efficacy and safety are comparable in Asian men remains insufficiently characterized.

METHODS

We conducted a PRISMA-guided review (PROSPERO CRD420251054772) and adhered to the SWiM framework for narrative synthesis. Databases searched in MEDLINE, Embase, Cochrane Library, and CINAHL from inception to 15 December 2024. Eligible studies presented Asian subpopulation outcomes for apalutamide + ADT in mCSPC from TITAN (final post hoc/data‑cut updates) and any independent Asian datasets. CASP critical appraisal was applied to selected studies; subgroup analysis was appraised for pre-specification, multiplicity, and reporting completeness. Overlapping publications were consolidated into the most mature dataset per endpoint.

RESULTS

Four TITAN‑derived analysis met the inclusion criteria. In Asian patients (N = 221), apalutamide + ADT showed benefits directionally consistent with the overall population for overall survival (OS, HR 0.68, 95% CI 0.42-1.13, P = 0.1335) and radiographic progression‑free survival (rPFS, HR 0.506, 95% CI 0.302-0.849, P = 0.009). Prostate-specific antigen (PSA) responses (PSA ≤ 0.2 ng/mL, PSA 50/90 decline: 73.9%, 90.1%, 74.8% and early deep declines) favored apalutamide. Time to PSA progression (TTPP, HR: 0.21, 95% CI 0.13-0.35, P < 0.0001), time to castration resistance (TTCR, HR 0.3, 95% CI 0.21-0.46, P < 0.0001), and second progression-free survival (PFS2, HR 0.76, 95% CI 0.44-1.29, P = 0.3022) were significantly improved. Skin rash appeared higher in Asian patients (30.9% any grade; 5.5% grade ≥ 3), typically manageable with standard measures, with no new safety signals emerging.

CONCLUSION

Asian subpopulation efficacy with apalutamide + ADT is directionally consistent with TITAN overall, with higher rash frequency that is generally manageable. Small subpopulation size and overlapping publications limit precision; regionally representative real‑world studies are needed.

TRIAL REGISTRATION: PROSPERO number CRD420251054772.