The TBCRC 048 trial led by Dr Nadine Tung evaluated the PARP inhibitor olaparib in women with metastatic breast cancer and germline PALB2 mutations. Among 24 patients with germline PALB2 variants, treatment responses were strikingly high. The overall response rate was 75%, with a clinical benefit rate of 83% at 18 weeks. Median progression-free survival was 9.4 months, and the median duration of response was 7 months. These results suggest that PALB2-associated breast cancers are highly sensitive to PARP inhibition, extending the potential benefit of these drugs beyond BRCA1/2 mutation carriers. The findings support considering PARP inhibitors as an effective targeted therapy option for patients with germline PALB2–mutated metastatic breast cancer.
Link to study https://pubmed.ncbi.nlm.nih.gov/41604601/