Talazoparib: Overall Survival Results in First-line Prostate Cancer Treatment

Major advances are occurring in metastatic castration-resistant prostate cancer (mCRPC). The United States Food and Drug Administration (FDA) approved, on June 20, 2023, for HRR-mutated patients, the combination of talazoparib (Talzenna, Pfizer) and enzalutamide . Updated data presented at the 2025 ASCO Genitourinary Cancers Symposiumprovided stronger evidence from TALAPRO-2 that this combination improves overall survival (OS).

FDA Approval: The First Step in 2023

The FDA approval made this combination available for HRR-mutated mCRPC. Initial TALAPRO-2 findings showed significantly longer radiographic progression-free survival (rPFS) and a particularly clear benefit in patients with BRCA mutations .

In advanced prostate cancer, homologous recombination repair (HRR) mutations occur in approximately 12% to 17% of patients. 

What Are HRR Gene Mutations?

HRR stands for "Homologous Recombination Repair," a mechanism cells use to repair DNA double-strand breaks. Broken DNA is repaired using a homologous, genetically similar DNA segment as a template. This enables accurate copying of genetic information while maintaining genetic diversity and stability. 

HRR mutations are changes in genes involved in this process, including ATM, ATR, BRCA1, BRCA2, CDK12, CHEK2, FANCA, MLH1, MRE11A, NBN, PALB2, and RAD51C.

These genes normally repair DNA and regulate cell division. Mutations disrupt normal function and may allow uncontrolled growth and division, leading to cancer.

Latest TALAPRO-2 Data

The study evaluated 399 HRR-mutated patients and found:

• Talazoparib plus enzalutamide significantly prolonged progression-free survival compared with placebo plus enzalutamide.
• In patients with BRCA mutations, treatment reduced progression risk by 80% (HR: 0.20).
• Patients with other HRR mutations also benefited (HR: 0.72).
• The most common adverse effects were anemia, neutropenia, and fatigue.

These data led to FDA approval for HRR-mutated patients. At the time, however, evidence about overall survival (OS) was insufficient.

Updated Data at the 2025 ASCO GU Symposium

In February 2025, San Francisco hosted the ASCO Genitourinary Cancers Symposium, where updated TALAPRO-2 results were presented. They supported the FDA approval and also demonstrated significantly improved overall survival (OS).

New findings included:

• Overall survival benefit:
  • Median OS was 45.8 months with talazoparib plus enzalutamide versus 37 months with placebo plus enzalutamide (HR: 0.796; P = 0.0155).
• Radiographic progression-free survival (rPFS):
  • With talazoparib, rPFS reached 33.1 months versus 19.5 months with placebo (HR: 0.667; P < 0.0001).
• Effect in patients without HRR mutations:
  • Some benefited, but the overall survival advantage was not statistically significant (HR: 0.782; P = 0.1008).
• Time to chemotherapy:
  • Time to starting chemotherapy reached 56.1 months with talazoparib and was shorter with placebo (HR: 0.568; P < 0.0001).

These findings showed that the combination not only slows progression but also extends overall survival. They also signal possible activity in patients without HRR mutations.

What Do the Updated Data Mean After FDA Approval?

The 2023 approval was an important step for HRR-mutated patients. Updated TALAPRO-2 results may further change practice by showing substantial benefit in the overall population.

The findings indicate:

• The combination now prolongs overall survival (OS), not only rPFS.
• Some benefits also occur without HRR mutations, although further subgroup analysis is needed.
• Long-term data strengthening the FDA approval position the combination as a first-line standard.

In conclusion, talazoparib plus enzalutamide may become a new standard in metastatic castration-resistant prostate cancer. Updated data support the FDA approval and suggest potential use in a broader patient population.