The Role of Maintenance Therapy in HER2+ Breast Cancer

EP: 1.Goals of Care for Patients with Early-Stage versus Advanced or Metastatic HER2+ Breast Cancer

EP: 2.Frontline Treatment Options for Early-Stage HER2+ Breast Cancer

EP: 3.Subcutaneous Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injections for Early-Stage HER2+ Breast Cancer

EP: 4.Subcutaneous Treatment of Early-Stage HER2+ Breast Cancer During the COVID-19 Pandemic

EP: 5.Discussing Treatment Decisions with Patients with Early-Stage HER2+ Breast Cancer

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EP: 6.The Role of Maintenance Therapy in HER2+ Breast Cancer

EP: 7.Exciting Developments in the HER2+ Breast Cancer Treatment Landscape

Sarah M. Tolaney, MD, MPH: When I think about maintenance therapy, I think about 2 different settings. One would be the metastatic setting looking at HP [trastuzumab, pertuzumab] maintenance, and [the other] someone who got induction THP [docetaxel, trastuzumab, pertuzumab] for first-line metastatic HER2 [human epidermal growth factor receptor 2]–positive disease. But I also think about maintenance in the early stage setting after someone achieved a PCR [pathologic complete response], and you’re getting your HP [trastuzumab, pertuzumab] to complete your year of therapy.

In the early stage setting, it’s very formulaic that you get your preoperative treatment and then you’re on HP [trastuzumab, pertuzumab] to complete a year. But in the metastatic setting, it’s a little more of an art than a science: when do you stop your induction therapy before going on to the maintenance approach? The data suggest that most people tend to get 6 to 8 cycles of induction taxane; many people are stopping after achieving robust responses. Some are stopping when patients are starting to develop some toxicity, such as neurotoxicity, and some doctors are going a little longer to make sure that response is a little more durable. It’s a little variable how we approach that.

With the maintenance setting and the metastatic setting, I tend to add endocrine therapy if that patient has ER [estrogen receptor]–positive, HER2+ disease to enhance that maintenance approach. We have some data to do this based on the data from PERTAIN, which looked at AI [aromatase inhibitor] therapy with either trastuzumab or trastuzumab with pertuzumab, and showed great outcomes with the AI–HP [trastuzumab, pertuzumab] combination. A lot of trials are ongoing trying to look at this maintenance setting to see if we can even do better. One example is PATINA, which looked at adding CDK4/6 inhibition with palbociclib [Ibrance] to the maintenance. We have an ongoing trial looking at adding tucatinib [Tukysa] to this maintenance setting, to see if we can help prolong disease control and maybe even prevent CNS [central nervous system] metastases. It’s a nice setting to think about novel ways to improve outcomes further.

Transcript edited for clarity.