Reshma Mahtani, DO, discusses considerations for use of trastuzumab duocarmazine in HER2+ breast cancer.
Sara Hurvitz, MD:Dr Mahtani, if trastuzumab duocarmazine is FDA approved, how will you position it in the treatment of your patients with metastatic breast cancer?
Reshma Mahtani, DO:That’s a great question and one that we’ll all grapple with, even in terms of T-DM1 [trastuzumab emtansine]. How will we position that? Now that we have multiple ADCs [antibody-drug conjugates], is there a cross-resistance and what’s the resistance mechanism? Can we expect 1 to work after the other 1 has stopped working? Is it resistance to the cytotoxic payload or is it resistance based on another mechanism? Even though this data doesn’t seem exciting in terms of absolute numbers, I am happy to see it because our patients are living longer and there’s a need for more novel therapies. It’s a good problem to have, and we’re discussing how to sequence these agents and what the resistance mechanisms are. But the short answer to your question is I would use it in a later line of therapy.
Sara Hurvitz, MD:I want to close out this module by asking a couple of polling questions. We need our audience to participate in stating which of the studies listed is most relevant to you: HER2CLIMB; DESTINY-Breast03 [NCT03529110], the phase 3 study we discussed in detail; the TULIP trial, the phase 3 study of trastuzumab duocarmazine; or DESTINY-Breast01 [NCT03248492] the single-arm study that led to the FDA approval of T-DXd [trastuzumab deruxtecan]? DESTINY-Breast03 is the winner; HER2CLIMB is also quite important here.
Second question, is the data from ESMO [European Society for Medical Oncology Annual Meeting]and the discussion you heard today likely to change your practice? Yes or no? For the vast majority, this is going to change your practice.
This transcript has been edited for clarity.