Would you use a PARP inhibitor in metastatic ER/PR positive breast cancer with somatic BRCA1 mutation but negative for germline mutation?

I certainly would. This is based on data from TBCRC 048 that showed efficacy in sBRCA1/2 as well as gPALB2.

Tung et al., PMID 33119476

The Tung et al. presentation of TBCRC 048 at ASCO 2020 was a phase II study of olaparib in metastatic breast cancer patients with germline, non-BRCA1/2 mutations OR somatic mutations in BRCA1/2 and other HR-pathway genes. The primary endpoint of this study was ORR. Fifteen patients had a somatic BRC...