FDA Approves Talazoparib With Enzalutamide for HRR-Mutated Metastatic Prostate Cancer

The FDA approved talazoparib (Talzenna; Pfizer) in combination with enzalutamide (Xtandi; Astellas, Pfizer) for adults with metastatic androgen pathway modulation-naïve or -sensitive (mAPMN/S) prostate cancer harboring homologous recombination repair (HRR) gene mutations detected by an FDA-authorized test. The October 26, 2026, decision brings the combination into an earlier prostate cancer treatment setting, with molecular testing determining eligibility.¹

The approval follows results from the phase 3 TALAPRO-3 trial (NCT04821622), which demonstrated a 52% reduction in the risk of radiographic progression or death compared with enzalutamide plus placebo. Overall survival (OS) data remained immature at the radiographic progression-free survival (rPFS) analysis.¹

TALAPRO-3 Establishes Progression Benefit

TALAPRO-3 was a randomized, double-blind, placebo-controlled trial enrolling 599 patients with HRR gene-mutated mAPMN/S prostate cancer. Participants were assigned 1:1 to receive daily enzalutamide with either talazoparib or placebo. All patients continued androgen deprivation therapy (ADT).¹

HRR mutation status was established prospectively using next-generation sequencing of tumor tissue or circulating tumor DNA. The evaluated genes were ATM, ATR, BRCA1, BRCA2, CDK12, CHEK2, FANCA, MLH1, MRE11A, NBN, PALB2, and RAD51C.¹

The primary efficacy outcome was investigator-assessed rPFS, evaluated using RECIST version 1.1 and Prostate Cancer Working Group 3 bone criteria. Median rPFS was not reached with talazoparib plus enzalutamide (95% CI, not reached–not reached), compared with 45.8 months with placebo plus enzalutamide (95% CI, 37.7–not reached). The hazard ratio was 0.48 (95% CI, 0.36–0.65; P < .0001).¹

Previously reported TALAPRO-3 findings provide additional context for the magnitude of benefit: estimated 3-year rPFS rates were 77% with talazoparib plus enzalutamide and 56% with the control regimen. These findings establish improved disease control; a survival advantage has not been established in this analysis.^1,2

Molecular Testing Guides Treatment Selection

The FDA noted that FoundationOne CDx and FoundationOne Liquid CDx had previously received approval as companion diagnostic devices to identify patients with prostate cancer harboring HRR gene alterations for talazoparib plus enzalutamide. The new indication requires an HRR gene mutation detected by an FDA-authorized test.¹

For pharmacists reviewing treatment initiation, confirming that the molecular report supports the prescribed indication is a practical first step. The trial enrolled a molecularly selected population, so its results should not be generalized to patients without qualifying HRR mutations. Documentation of testing also supports communication between the oncology team and the dispensing pharmacy.¹

Oral Dosing Requires Continued ADT

The recommended talazoparib dosage for the newly approved indication is 0.5 mg orally once daily with enzalutamide until disease progression or unacceptable toxicity. Patients must also receive a gonadotropin-releasing hormone analog unless they have undergone bilateral orchiectomy.^1,3

Enzalutamide’s prescribing information recommends 160 mg orally once daily, with or without food. Pharmacists should reinforce that the oral combination does not replace ongoing medical or surgical castration. Medication reconciliation should also address enzalutamide’s potential to alter exposure to concomitant medications.⁴

Myelosuppression Makes Monitoring Essential

Talazoparib’s warnings include myelodysplastic syndrome/acute myeloid leukemia (MDS/AML), myelosuppression, and embryo-fetal toxicity. In the reported TALAPRO-3 results, grade 3 or higher anemia occurred in 51% of patients receiving talazoparib plus enzalutamide compared with 3% receiving the control regimen. Anemia led to talazoparib discontinuation in 5% of patients.^1,2

Talazoparib’s prescribing information directs monthly blood count monitoring during treatment. Prolonged hematologic toxicity requires treatment interruption and closer monitoring, with hematology evaluation if recovery does not occur within the specified interval. Confirmed MDS/AML requires discontinuation. Pharmacists can reinforce prompt reporting of worsening fatigue or unusual bleeding and help coordinate laboratory follow-up before refills.³

Enzalutamide adds considerations involving falls and fractures, as well as seizure risk. Reviewing baseline fall risk and medications that affect seizure threshold can help individualize counseling. Together, molecular eligibility review and active toxicity follow-up give pharmacists concrete roles in implementing the expanded indication.⁴

REFERENCES

1. FDA approves talazoparib with enzalutamide for metastatic androgen pathway modulation-naïve or -sensitive prostate cancer with HRR gene mutations. News release. FDA. Published October 26, 2026. Accessed October 26, 2026. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-talazoparib-enzalutamide-metastatic-androgen-pathway-modulation-naive-or-sensitive?utm_medium=email&utm_source=govdelivery

2. TALZENNA plus XTANDI improves radiographic progression-free survival by more than 50% in metastatic prostate cancer. News release. Pfizer. Published May 30, 2026. Accessed October 26, 2026. https://www.pfizer.com/news/press-release/press-release-detail/talzenna-plus-xtandi-improves-radiographic-progression-free

3. Talzenna. Prescribing information. Pfizer. Accessed October 26, 2026. https://labeling.pfizer.com/ShowLabeling.aspx?id=11046

4. Xtandi. Prescribing information. Astellas Pharma US. Accessed October 26, 2026.https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/203415s026;213674s016lbl.pdf