Maintenance Regimens Expand in HER2-Positive Metastatic Breast Cancer

At the American Society of Clinical Oncology (ASCO) meeting, updated HER2CLIMB-05 findings on the addition of tucatinib (Tukysa) to first-line maintenance therapy with trastuzumab (Herceptin) and pertuzumab (Perjeta) added to a growing conversation about maintenance strategies in HER2-positive metastatic breast cancer.

In this exclusive MedPage Today video, Erika Hamilton, MD, of the Sarah Cannon Research Institute in Nashville, Tennessee, discusses how HER2CLIMB-05, PATINA, and DESTINY-Breast09 may shape future treatment strategies.

Following is a transcript of her remarks:

Previously reported was that adding tucatinib to HP [trastuzumab and pertuzumab] maintenance essentially lengthened progression-free survival by almost 9 months. What we presented in an update at ASCO 2026 was some of this data around progression-free survival as well as objective response rate and duration of response in a few key subgroups, key subgroups being hormone receptor status, brain metastases, and whether metastatic disease was de novo or recurrent.

Which patients to consider this for is a very timely question. So there’s another maintenance regimen out there. This is the PATINA regimen. This is adding palbociclib (Ibrance). That regimen, patients are only eligible for that if they have HR [hormone receptor]-positive disease. So HER2CLIMB really encompasses a broader population than PATINA. So it includes all patients that are hormone receptor negative. So certainly that patient population.

I do think for our hormone receptor-positive patients, we really can consider HER2CLIMB-05 as well as PATINA. I think the PATINA data is quite compelling, might lean a little bit more towards HER2CLIMB-05 if patients have brain metastases.

And then the other thing to consider is that we now have DESTINY-Breast09, which is trastuzumab deruxtecan (T-DXd; Enhertu) in combination with pertuzumab, approved in the first-line setting. And that trial did not take into account any option of maintenance. This was really just treat until progression.

And so as often happens in the breast cancer world, we move at a pretty quick pace. And so sometimes we have to go off the reservation a little bit without data and decide what we’re going to do without good randomized trial data to support us. And I think that a lot of our patients are telling us that they really are interested in maintenance strategies to be able to be off, not have to receive a cytotoxic chemotherapy really contributes to a good quality of life. And so I do think we’re still going to be considering these maintenance regimens even if patients do get induction with T-DXd plus pertuzumab.

But what I do think we’re learning more about, and there were some presentations at ASCO looking at how long should we probably give T-DXd plus pertuzumab. I do think it would probably be a mistake to just treat with a fixed number of cycles. I personally, we would be treating until maximal response and it looks like that’s probably longer. It probably looks like that’s at least maybe a year, more towards 11 or 13 months of T-DXd, not just six cycles like we’re used to.