KRISTINE.

Headline: Final results of the KRISTINE trial are here. As a reminder, it looked at replacing good ole TCHP with the chemo-free combo pertuzumab and trastuzumab emtansine (T-DM1) for HER2(+) breast cancer. Initial results showed fewer side effects, but also a 10% lower rate of pathologic complete response. Turns out the T-DM1+P regimen also had more progression events prior to surgery. During neoadjuvant therapy, 7% of patients receiving T-DM1+P had locoregional progression compared to 1% for TCHP. This translated into a nearly 10% decrease in 3-year progression-free survival (PFS) from 94→ 85%. While PFS was technically similar after surgery, it didn’t include the folks who progressed during neoadjuvant therapy. So even though toxicity during neoadjuvant therapy was less with T-DM1+P, adjuvant toxicity was worse due to so many patients getting cytotoxic chemo after partial responses. TBL: Womp womp, chemo-free neoadjuvant T-DM1 + pertuzumab has a lower response rate and higher risk of pre-op progression than standard TCHP. | Hurvitz, J Clin Oncol 2019