mHSPC), first-line¶

Abstract: LBA5007 · Session: Genitourinary Cancer — Prostate, Testicular, and Penile (late-breaking oral), 2026 ASCO Annual Meeting · Presenter: Neeraj Agarwal, MD, FASCO (Huntsman Cancer Institute, University of Utah, Salt Lake City) · Embargo: ASCO 2026 (May 29 – Jun 2, 2026)

At a glance¶

Sponsor: Pfizer (Talzenna); enzalutamide co-developed/co-promoted by Astellas Pharma and Pfizer
PI / presenter: Neeraj Agarwal, MD, FASCO (Huntsman Cancer Institute, University of Utah)
NCT ID: NCT04821622
Phase: 3
Design: Double-blind, randomized, placebo-controlled; talazoparib + enzalutamide vs placebo + enzalutamide in patients with HRR/DDR gene-altered mCSPC
N: 599 randomized (HRR-deficient cohort)
Primary endpoint(s): Radiographic progression-free survival (rPFS) by blinded independent central review
Comparator: Placebo + enzalutamide
Indication: Metastatic castration-sensitive prostate cancer (mCSPC / mHSPC) with HRR/DDR gene alterations
Line: First-line for metastatic castration-sensitive disease

Headline result¶

Talazoparib + enzalutamide significantly prolonged radiographic progression-free survival versus enzalutamide alone in HRR gene-altered mCSPC, reducing the risk of radiographic progression or death by 52% (HR 0.481, 95% CI 0.357–0.647, p<0.0001). Median rPFS was not reached with the combination versus 45.8 months with placebo plus enzalutamide; 3-year rPFS was 77% vs 56%. The benefit was deepest in BRCA-mutated tumors (HR 0.368) and remained favorable in the non-BRCA HRR subgroup (HR 0.567). Overall survival was immature at this interim analysis but trended in favor of the combination (74 vs 91 deaths; HR 0.767), without reaching statistical significance. The safety profile was consistent with the known profiles of each agent; the most common all-grade treatment-emergent adverse events with the combination were anemia, fatigue, decreased neutrophil count, neutropenia, asthenia, and decreased white blood cell count, with 18.7% discontinuing talazoparib due to adverse events. Results were simultaneously published in the New England Journal of Medicine.

Mechanism / class¶

Talazoparib is an oral PARP inhibitor that traps PARP at sites of single-strand DNA breaks, producing synthetic lethality in tumors with homologous recombination repair (HRR/DDR) defects such as BRCA1/2 alterations. Enzalutamide is an oral androgen receptor pathway inhibitor (ARPI). The combination is already approved for first-line HRR-mutated metastatic castration-resistant prostate cancer (mCRPC) on the strength of TALAPRO-2; TALAPRO-3 extends the PARP-inhibitor + ARPI strategy earlier, into the castration-sensitive setting.

Discussant takeaway¶

Framed as moving genomically targeted, PARP-inhibitor-based therapy upstream into the castration-sensitive setting for HRR-altered disease, with the largest absolute benefit in BRCA-mutated tumors but a signal extending across the broader HRR-defined population; overall survival follow-up remains the key confirmatory readout.

Practice-changing?¶

Pending → likely yes for HRR-altered mCSPC. A 52% reduction in radiographic progression/death with a positive primary endpoint and NEJM publication establishes talazoparib + enzalutamide as a compelling first-line option for HRR/BRCA-altered metastatic castration-sensitive disease, and supports universal HRR genomic testing at diagnosis. Confirmatory practice change for the broad population awaits mature overall survival data; the BRCA-mutated subgroup benefit is already strongly supportive.

Cross-links¶

Other ASCO 2026 trials: PROTEUS — perioperative apalutamide + ADT, high-risk localized prostate cancer · ARACOG — darolutamide vs enzalutamide, cognition head-to-head

Sources¶

ASCO Meeting Library (Abstract LBA5007), 2026 ASCO Annual Meeting; simultaneous publication in the New England Journal of Medicine
EMJ: https://www.emjreviews.com/oncology/news/asco-2026-talapro-3-delays-prostate-cancer-progression/
Urology Times: https://www.urologytimes.com/view/talapro-3-talazoparib-plus-enzalutamide-improves-rpfs-hrr-gene-altered-mcspc
Targeted Oncology: https://www.targetedonc.com/view/talazoparib-enzalutamide-shows-improved-radiographic-pfs-in-metastatic-castration-sensitive-prostate-cancer
Managed Healthcare Executive: https://www.managedhealthcareexecutive.com/view/new-trial-results-point-toward-a-more-targeted-approach-to-metastatic-castration-sensitive-prostate-cancer-asco-2026
Pfizer press release (via StockTitan): https://www.stocktitan.net/news/PFE/talzenna-plus-xtandi-improves-radiographic-progression-free-survival-o0b0fqf8vswg.html