Clinical Cases in HER2+ Breast Cancer - Episode 9

Case 1: Subcutaneous Trastuzumab-Pertuzumab for HER2+ Breast Cancer 

Ruta Rao, MD: In the context of COVID-19 [coronavirus disease 2019], let’s talk about the subcutaneous therapeutic options and the potential benefits we’ve seen with using the subcutaneous formulations of pertuzumab and trastuzumab.

Sara Tolaney, MD, MPH: I’ve been excited about subcutaneous HP [trastuzumab, pertuzumab], particularly during the time of COVID-19, when it could potentially get patients in and out of infusion quite quickly. We have initially seen data from the FeDeriCa trial, which looked at the efficacy of subcutaneous trastuzumab-pertuzumab compared with IV [intravenous] HP [trastuzumab, pertuzumab]. It looked at patients getting up-front anthracycline-based therapy followed by a taxane with either subcutaneous or IV HP [trastuzumab, pertuzumab], and it found identical pCR [pathologic complete response] rates between the 2 arms, suggesting that the efficacy is the same. They have also looked at drug levels, which were the same.

We’ve seen data now from the PHranceSCa study, which looked at patient preferences. This study had a clever design because patients could get IV HP [trastuzumab, pertuzumab] or subcutaneous HP [trastuzumab, pertuzumab] and then switch over to what they didn’t get. The patients then looked at which they preferred and could then choose to continue on whichever formulation they liked more. It was clear from this data that patients preferred getting the subcutaneous HP [trastuzumab, pertuzumab] over getting IV HP. When you look at the toxicity profiles,what we see is that there can be some injection-site reactions to the subcutaneous HP [trastuzumab, pertuzumab], but outside that, there were no worse toxicities compared with IV HP [trastuzumab, pertuzumab]. We’re excited about the option of being able to administer a fixed-dose infusion quite quickly; it doesn’t take calculation by the pharmacist for dosing. It’s a quick 10-minute subcutaneous injection.

There is a lot of work ongoing to see if this is something that could be administered at home by home-infusion nurses because there is a huge movement toward doing this with COVID-19 and trying to keep patients out of the infusion center. There’s an ongoing trial looking at the feasibility of using home nursing to give subcutaneous HP [trastuzumab, pertuzumab]. Hopefully, it would be a movement with further work that we could get toward because it would be great for patients, particularly in the adjuvant setting, when they’re on just HP [trastuzumab, pertuzumab] maintenance, not to have to come into infusion every 3 weeks.

Ruta Rao, MD: Right. Dr Jhaveri, has your group [at Memorial Sloan Kettering Cancer Center] transitioned to using the subcutaneous formulation?

Komal Jhaveri, MD, FACP: Yes. We definitely have options including biosimilars for trastuzumab and subcutaneous options for our patients with trastuzumab already. We’re also going to be participating in the clinical trial that Dr Tolaney was talking about. We’re going to try to do subcutaneous injections for both trastuzumab and pertuzumab in patients’ homes. This is a clever study design, and this is the wave of the future given what we’ve learned about how to deal with COVID-19. It was enlightening to me that this was already happening in certain European countries. In the United Kingdom, it was a standard practice for nurses to go to homes and administer even fulvestrant to the patients. This is something that, in the United States, we’ve not seen. But given the situation we’re in, this is timely, and it’s something that our patients will be able to benefit from in terms of convenience and exposure.

Ruta Rao, MD: I want to thank all 3 of you very much for a robust discussion on the treatment of early stage HER2 [human epidermal growth factor receptor 2]–positive breast cancer. With that, we’re going to move to our next case, Dr Jhaveri’s case: a patient with relapsed/refractory hormone receptor-negative, HER2-positive metastatic breast cancer.

Transcript edited for clarity.