Testing PD-1 Inhibition With Neoadjuvant Anti-HER2 Therapy in Breast Cancer

At the American Society of Clinical Oncology (ASCO) annual meeting, researchers reported on a multicenter, phase II trial exploring the efficacy and safety of adding pembrolizumab (Keytruda) to the standard-of-care treatment of paclitaxel (Taxol), trastuzumab (Herceptin), and pertuzumab (Perjeta; THP) in chemotherapy-naive patients with invasive, HER2-positive breast cancer.

In this exclusive MedPage Today video, Jin Sun L. Bitar, MD, a breast oncologist from Cedars Sinai Medical Center in Los Angeles, explained the study background and design.

Following is a transcript of her remarks:

The neoHIP trial is a prospective, multicenter trial for HER2-positive early-stage breast cancer. So the trial was designed to test adding immune checkpoint inhibitor pembrolizumab to the standard-of-care HER2-targeted and chemo-based neoadjuvant regimen.

So the study was opened [in] 2018 with the study arms. So arm A we call THP, so that’s paclitaxel, trastuzumab, and pertuzumab. And then arm B is that arm A plus pembrolizumab, so with the immune checkpoint inhibitor. And arm C is paclitaxel with trastuzumab. But after our pre-analysis, we closed arm C.

So we have two arms, arm A and arm B. Our goal is 58 patients in each arm. So far I think we enrolled a little bit more than 30 patients in each arm. So the primary endpoint is pCR [pathologic complete response]. We are expecting the report soon.

There were a lot of clinical trials [testing] the immune checkpoint inhibitor for the advanced setting in HER2-positive disease, but it didn’t really show good efficacy. So I think we need to use that immune checkpoint more in the early setting. So like now the neoadjuvant trial we have, because the chemotherapy actually changes the immune microenvironment, the tumor. So if wait until end of lines, then it wouldn’t work. So that’s why we wanted to bring this immunotherapy in the early setting. So hopefully we can decrease the chemo toxicity by adding immune checkpoint inhibitor.