Is DESTINY Breast-09 data sufficient for T-DXd/P to replace THP as the first line standard of care for HER2-positive metastatic breast cancer?

With the impressive improvement in PFS to a 1L PFS to a remarkable 40.7 months, T-DXd + P is definitely an attractive option. However, I do not think this will be an approach I use for all patients. For ER+ patients, a THP induction strategy, followed by maintenance HP + AI and palbociclib, is also ...

I do think it is sufficient to drive a change in the standard of care and allow for T-DXd/P to be an option for 1L HER2+ MBC. I don't think this means that all patients need to receive T-DXd/P, given the toxicity profile as well as the potential for a THP induction followed by PATINA or HER2CLIMB-05...

Currently, T-DXd is the category 1 preferred second-line agent after THP. If T-DXd is used first-line, the second-line landscape becomes less well-defined. Early retrospective data suggest that tucatinib/trastuzumab/capecitabine after T-DXd has modest activity (median PFS ~4.7–5.2 months), which is ...

Although T-DXd + P is an option, I would wait to use this as a first-line regimen unless the tumor burden is high: Most of us are using THP at this time. In the DESTINY-Breast09 trial, the THP cohort of patients did better than the CLEOPATRA study patients in terms of PFS, which could be related to ...