The US Food and Drug Administration (FDA) has approved the oral PARP inhibitor talazoparib (Talzenna, Pfizer) plus enzalutamide (Xtandi) to treat homologous recombination repair (HRR) gene–mutated metastatic castration-resistant prostate cancer.
Talazoparib is already approved for adults with deleterious or suspected deleterious germline BRCA-mutated HER2-negative locally advanced or metastatic breast cancer. The new approval, granted following priority review, is based on findings from the randomized, placebo-controlled, phase 3 TALAPRO-2 trial, published earlier this month in The Lancet.
The 399 patients in the study were randomly assinged in a 1:1 ratio to receive either enzalutamide 160 mg daily plus either talazoparib 0.5 mg or placebo daily. Median radiographic progression-free survival (PFS) was not reached in the treatment group; it was 13.8 months in the placebo group (hazard ratio [HR], 0.45). In an exploratory analysis by BRCA mutation status, patients with BRCA-mutated disease who received talazoparib exhibited an even stronger median radiographic PFS (HR, 0.20; not reached vs 11 months) in comparison with those without BRCA-mutated disease (HR, 0.72; 24.7 vs 16.7 months).
Serious adverse reactions occurred in 30% of patients who received talazoparib plus enzalutamide. The most common serious adverse reactions, reported in more than 2% of patients, included anemia (9%) and fracture (3%). Discontinuation of talazoparib occurred in 10% of patients, according to a Pfizer statement.
Pfizer also noted that a marketing authorization application for the drug combination has been accepted for review by the European Medicines Agency.
"Despite treatment advancement in metastatic castration-resistant prostate cancer, the disease can progress quickly, and many patients may only receive one line of therapy," lead investigator Neeraj Agarwal, MD, of the Huntsman Cancer Institute, University of Utah, said in a statement. Patients with metastatic castration-resistant prostate cancer harboring HRR genetic alterations have even worse outcomes, and thus the FDA's approval of the talazoparib and enzalutamide combination "represents a treatment option deserving of excitement and attention."
Sharon Worcester, MA, is an award-winning medical journalist based in Birmingham, Alabama, writing for Medscape, MDedge and other affiliate sites. She currently covers oncology, but she has also written on a variety of other medical specialties and healthcare topics. She can be reached at email@example.com or on Twitter: @SW_MedReporter.
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Cite this: FDA Approves Talazoparib for Metastatic Prostate Cancer - Medscape - Jun 21, 2023.