A focused discussion on the subcutaneous formulation of trastuzumab and pertuzumab in patients with early-stage HER2+ breast cancer.
Sara A. Hurvitz, MD: Now I want to talk to you about living in an era while dealing with a pandemic. Hopefully, it is a little better controlled than it's been in the last couple of years, but patients aren't super eager to be sitting in crowded infusion rooms. We now have the availability of subcutaneous fixed-dose trastuzumab/pertuzumab, which allows for patients to be in and out of the clinic more quickly. In certain circumstances, even receive home injections omitting the visit to the clinic itself. Sara, I was hoping you could take us through the data supporting SubQ [subcutaneous] use of HP [trastuzumab, pertuzumab]. Then I want to talk to you both and see if you are using this in your own clinics.
Sara M. Tolaney, MD, MPH: Sure, I think this is really nice to have available for patients. There are a couple of trials that have been done evaluating (1) the efficacy of the drug, and then (2) patient preference. I think both are really critical features when thinking about it. One of the largest studies that's looked at comparison of efficacy is the FeDeriCa trial. This was really a preoperative trial, again looking at anthracycline taxane therapy given with IV [intravenous] HP or with subcutaneous HP. The study was looking at drug levels; it was predominantly looking at the C trough level of the pertuzumab given subcutaneously and comparing that to what they would know of with the IV formulation. Certainly, the concentration of drug was really the same; however, I think what people were really most interested in is also efficacy based on pCR. When you look at pCR and comparing both the SubQ to the IV formulation, you see it's identical. This taught us that drug levels are the same and efficacy is the same with SubQ and IV. So then came the issue about patient preference. The PHranceSCa study did a very clever design with this, where they took people and gave them the opportunity to start off with 1 way, either IV or SubQ, then go on to get it the other way and then pick which 1 they liked the most and then continue that. The vast majority, over 80% of people, preferred the subcutaneous formulation over the IV formulation. This suggested that when people have had the experience of both, that's what they like. What we've found in clinic is if someone doesn't have a port, it's nice that they don't have to worry about IV access issues. That becomes a nice thing—to avoid getting a port potentially; you are in and out of clinic much faster as you are alluding to. You think about the time it takes to get an IV infusion of 1, then you wait and then you get the IV infusion of the other compared to just a 5-to-8-minute subcutaneous injection in your anterior thigh, and you are in and out of infusion. For us, it's also the preparation time that it takes our pharmacy time to prepare the IV formulation; that's another set of time on the back end. It is great for our infusion center to be able to see more patients in infusion, and it is great for patients to get in and out of clinic. Obviously, the next question is, can you get it at home and prevent the whole visit entirely? Our group has been participating in a trial where they were sending a nurse to the patient's house to administer the subcutaneous formulation that our patients have really enjoyed getting, which has been great. They're presenting data at ASCO [American Society of Clinical Oncology] 2022 this year from that subcutaneous home administration trial. The challenge is it isn't ready for patients to give on their own yet at home. There is work ongoing, looking at self-injectors. I think we'll see more in the years to come, but for now, it really is predominantly administered in an infusion center.
Sara A. Hurvitz, MD: Thank you for that nice description. I must say my experience with patients where I'm sharing their care with the community oncologist is that many community oncologists aren't aware of the availability of this. It must be exceedingly challenging to keep up with the speed of data when you’re treating so many different tumor types. So, I have recommended this for certain patients and they go to their community oncologist, and it’s the first time they’ve heard of it. I think going through these data are important for us to understand the availability. This is FDA [United States Food and Drug Administration] approved in the neoadjuvant and adjuvant setting in combination with chemotherapy and also in the frontline setting for metastatic breast cancer. I'm interested to hear from you, Bill. Are you using this? If you are, are you starting it with the chemotherapy because patients already have to come into the clinic to get the chemotherapy, and are there for an IV infusion? Do you start it from the outset or are you using it during the maintenance phase?
William J. Gradishar, MD: I would make a general comment that, as a community, we're probably underutilizing this for all the reasons that Sara [Tolaney, MD, MPH] described. It is essentially superimposable with the IV preparation guidelines that suggest wherever IV HP is used, you could use this instead with equal efficacy, equal toxicity. To your question about whether we use it from the outset, in the patients where I have used it, that is what we have done, and they’ve liked it. It would be fantastic if it turns out that this can be done at home; that would be the true winner. Not having patients have to come downtown and look for a parking spot for as long as their entire treatment takes; I think that this is something that's underutilized, but something that should be more widely disseminated.
Sara A. Hurvitz, MD: Yes, I agree completely.
Transcript edited for clarity.