Would you consider a PARPi for a patient with PALB2 mutated metastatic triple negative breast cancer?

PARP inhibitors currently have FDA approval for treatment of breast cancer in patients with HER2 negative disease who carry a BRCA 1 or BRCA 2 mutation, but not other familial (germline) genetic mutations and they are not approved for tumor (acquired) genetic mutations.

Theoretically, PARP inhibito...

Yes, I would consider it given the data from TBCRC-048 showing high response rates to germline PALB2 mutated breast cancer. I would use it in the same sequence as a BRCA1/2 mutated TNBC (after immunotherapy if it was indicated based on the CPS score) if I can get it approved.

I would consider it as a later option, especially if toxicity is an issue. The data is still limited in my view (Tung et al., PMID 33119476).