Pfizer said that Talzenna (talazoparib) combined with Xtandi (enzalutamide) has improved survival outcomes in the Phase 3 TALAPRO-2 study of certain prostate cancer patients.
According to the results, the combination showed a significant improvement in overall survival.
TALAPRO-2 assessed Talzenna combined with Xtandi in patients with metastatic castration-resistant prostate cancer (mCRPC), with or without homologous recombination repair (HRR) gene mutations.
The multicentre, randomised, placebo-controlled trial enrolled 1,035 patients.
Participants were divided into two cohorts: 800 unselected patients (Cohort 1) and those selected for HRR gene mutations (Cohort 2).
Overall survival (OS) was a key secondary endpoint in the study. After a median follow-up of 52.5 months, the median OS in Cohort 1 was 44.5 months with Talzenna plus Xtandi, compared to 38.0 months with Xtandi plus placebo.
This resulted in a 22% reduction in the risk of death, marking nearly a 6.5-month improvement in median OS over the standard of care.
In Cohort 2, patients with HRR-mutated mCRPC showed a significant and clinically meaningful improvement in OS.
After a median follow-up of 43.9 months, the median OS was 42.1 months with Talzenna plus Xtandi, compared to 31.3 months with Xtandi and placebo.
This resulted in a 33% reduction in the risk of death, representing a 10.8-month gain in median OS compared to the standard of care in a patient group with a historically poor prognosis.
At the final analysis, updated radiographic progression-free survival (rPFS) and other secondary efficacy endpoints showed sustained clinical benefits in both cohorts, consistent with prior primary analysis results.
Pfizer chief oncology officer Roger Dansey said: “These latest data from TALAPRO-2 are extremely compelling, demonstrating that the combination significantly extended overall survival, in patients selected and unselected for HRR gene alterations, potentially shifting the treatment paradigm for all men living with mCRPC.
“Although definitive conclusions cannot be drawn across studies, these results appear to represent the longest median overall survival reported in a randomised, controlled Phase 3 trial in mCRPC.”
Pfizer has shared these data with the US Food and Drug Administration (FDA), the European Medicines Agency (EMA) and other global health authorities to support potential updates to the approved labels for Talzenna.
Talzenna was initially approved for HER2-negative breast cancer.
In June 2023, the FDA approved Talzenna with Xtandi for HRR gene-mutated mCRPC. The European Commission approved the combination in January 2024 for mCRPC patients without chemotherapy indications.
