How are you deciding between T-DXd/pertuzumab and THP> HP/tucatinib in patients with metastatic HER2+ breast cancer?

I am reserving HP/tucatinib to the maintenance setting (after 1L THP, as was studied in HER2CLIMB-05, but also will plan to offer it as maintenance after 1L T-DXd/P in patients who experience cumulative toxicity on T-DXd/P and need to stop). I would tend to offer HP/tucatinib maintenance to those wi...

Tucatinib is probably a little better for brain mets, although certainly T-DXd can treat brain mets. If a patient relapses in the brain while getting HP, then the value of HP continuation is likely to be low.

The decision between these two options hinges on efficacy magnitude, toxicity profile (particularly ILD risk), CNS considerations, treatment sequencing implications, and overall survival data maturity.

In the first-line metastatic setting, current NCCN guidelines list THP as category 1, preferred for...