Real-world clinical outcomes of apalutamide versus abiraterone with androgen deprivation therapy for metastatic hormone-sensitive prostate cancer.

BACKGROUND

Metastatic hormone-sensitive prostate cancer (mHSPC) is an aggressive disease with a poor prognosis. Current treatment guidelines recommend combining androgen receptor axis-targeted therapies (ARATs) with androgen deprivation therapy (ADT) for mHSPC. While individual ARATs have shown success, few studies directly compare their effects.

AIM: To compare the safety and clinical outcomes of abiraterone acetate (abiraterone) and apalutamide in chemotherapy-naïve mHSPC patients, focusing on prostate-specific antigen (PSA) kinetics, safety, and survival outcomes.

METHOD: A retrospective, single-centre study included 107 chemotherapy-naïve mHSPC patients treated with abiraterone or apalutamide plus ADT. PSA levels were measured at baseline and during treatment. Primary outcomes were PSA progression-free survival (PSA-PFS) and overall survival (OS). Adverse events were recorded. Inverse probability treatment weighting adjusted baseline differences.

RESULTS

Median PSA-PFS significantly favoured apalutamide (log-rank p = 0.015). Achieving PSA ≤ 0.02 ng/mL was strongly associated with delayed progression (HR 0.07, 95% CI 0.02-0.28; p < 0.001). OS did not differ significantly between groups (p = 0.504). Apalutamide achieved lower median nadir PSA (0.02 ng/mL vs. 0.23 ng/mL, p < 0.001) and shorter mean time to nadir (4.5 vs. 7.2 months, p = 0.001), with more patients reaching ultralow PSA levels (≤ 0.02 ng/mL) during follow-up. Adverse events occurred more frequently with apalutamide (71.2% vs. 46.5%, p = 0.015), with fatigue and rash being the most common.

CONCLUSION

Apalutamide demonstrated deeper and more sustained PSA reductions, translating into delayed disease progression compared to abiraterone. Both treatments were generally well tolerated, though adverse events were more prevalent with apalutamide.