The Evolving HER2+ Metastatic Breast Cancer Treatment Landscape - Episode 4

Patient Case #1: Frontline Therapy for HER2+ mBC

, , ,

Using a patient case to center their discussion, the panel reviews frontline treatment options for HER2+ metastatic breast cancer and the rationale behind selection.


Andrew D. Seidman, MD: If we could bring up the first patient case that I’ll present to our panel, this is a 65-year-old woman, and she presents with a 3.5-cm right breast mass. She has 2 ipsilateral palpable axillary nodes. And a biopsy of the breast mass does show that she has hormone receptor-negative and HER2-overexpressed breast cancer. And unfortunately, an extensive disease evaluation revealed 2 lesions in the liver. We’ll assume that she’s had a biopsy, and this confirms the same phenotype. This is a de novo metastatic presentation of oligo liver metastasis in a 65-year-old. If we go to the next slide now, we have our polling question. I’m going to ask those of you listening to decide. Where would you go with first-line treatment for this 65-year-old with hormone receptor-negative, HER2-positive breast cancer who presents with 2 liver lesions? She’s not in visceral crisis. Would you use, 1, pertuzumab, trastuzumab, and docetaxel; 2, pertuzumab, trastuzumab, and paclitaxel; 3, just the 2 antibodies; or 4, carboplatin with paclitaxel and trastuzumab? I’ll let you vote. This is interesting. You can consider CLEOPATRA in terms of first-line therapy. Some doctors may have their favorite taxane.

The most popular regimen is weekly paclitaxel with trastuzumab and pertuzumab followed by docetaxel-HP [trastuzumab, pertuzumab]. Very few people chose to give antibodies alone or carboplatin with antibodies. Any high-level, quick thoughts on these results? Surprising? Not surprising to you?

Mark Pegram, MD: Weekly paclitaxel is better tolerated in a 65-year-old than is docetaxel, so that’s why I chose weekly paclitaxel-based treatment.

Ruta Rao, MD: I agree. And choices 1 or 2, obviously, are based on the CLEOPATRA data, which Dr Pegram explained very nicely at the beginning.

Andrew D. Seidman, MD: Have you ever found a patient where you’d give dual antibodies but not chemotherapy?

Mark Pegram, MD: Yes, every once in a while, when you have someone who has an absolute contraindication to chemotherapy or who flat out refuses chemotherapy. It comes up occasionally, but fortunately, it’s rare. But I’ve done it.

Andrew D. Seidman, MD: And I know this is something that we may cover later. And people have asked about it in the chat room, thoughts about, if we invented this patient as hormone receptor-positive and HER2-positive, and you proceeded down the taxane, HP [trastuzumab, pertuzumab] path, when and where do you insert antiestrogen therapy? Ruta, do you want to take that?

Ruta Rao, MD: In a patient like this, after I get a nice response, 3 or 6 months with the taxane and the dual antibody, when you get to the point where you’re going to hold the taxane and just continue them on the dual antibody, if they’re strongly hormone receptor-positive, that’s when I would consider adding some endocrine therapy.

Andrew D. Seidman, MD: And that arm D, paclitaxel, carbo [carboplatin], and trastuzumab], was chosen by a very small proportion. I’m wondering if there was a concern about taxane toxicity in a 65-year-old. Mark, any thoughts on carboplatin monotherapy?

Mark Pegram, MD: Yes. It’s not as active as taxane. It’s that simple. And moreover, taxane, carbo [carboplatin], trastuzumab has been compared head-to-head with docetaxel, trastuzumab. And the results were that the carboplatin is dispensable. However, in that trial, the dose of docetaxel was asymmetric. It was 100 mg/m2 in the TH [docetaxel, trastuzumab] arm and only 75 mg/m2 in the TCH [docetaxel, carboplatin, trastuzumab]arm. Moreover, the TCH arm had a little bit smoother safety profile. But with paclitaxel, carbo [carboplatin] you could use the weekly low-dose regimen of 80 mg/m2 paclitaxel and carbo [carboplatin] of 2 weekly. And that is extremely well tolerated, even in a 65-year-old. I have no objection to that regimen. It is less toxic than docetaxel as the backbone.

Transcript edited for clarity.