In a conversation with CancerNetwork®, Amy Tiersten, MD, spoke about how findings from the phase 1/2 ASPIRE trial (NCT03304080) may support anastrozole (Arimidex) plus palbociclib (Ibrance), trastuzumab (Herceptin), and pertuzumab (Perjeta) as a first-line treatment for patients with hormone receptor (HR)–positive, HER2-positive metastatic breast cancer.

Data presented at the 2023 San Antonio Breast Cancer Symposium (SABCS)highlighted a clinical benefit rate of 97% (95% CI, 83%-100%; P <.0001) and an objective response rate of 73% (95% CI, 54%-88%) in patients who received the experimental regimen. Moreover, investigators reported a median time to overall response of 2.8 months (95% CI, 2.7-5.2) and a median duration of response of 37.8 months (95% CI, 14.0-not estimable).

The anastrozole-based combination produced a median progression-free survival (PFS) of 21.2 months (95% CI, 18.4-57.2), with PFS rates of 46.1% (95% CI, 30.2%-70.4%) at 24 months and 24.6% (95% CI, 10.4%-58.3%) at 48 months. Additionally, the median overall survival had not been reached at the time of the analysis; only 1 of 30 patients died after more than 2 years of study treatment.

Based on these findings, Tiersten, a professor of Medicine and clinical director of Breast Medical Oncology at Mount Sinai Hospital, spoke to the importance of having an alternative treatment option outside of chemotherapy in this patient population. She stated how administering this study regimen in the frontline may help patients avoid some of the common toxicities associated with chemotherapy, thus benefitting their quality of life.

“It’s hugely important if we can have that kind of clinical benefit rate and the duration of the response and have patients avoid the toxicities of chemotherapy such as hair loss, neutropenia, fever, and nausea—all the known [adverse] effects that come with chemotherapy,” Tiersten said. “Quality of life is always important, but it’s especially important in a group of patients in whom we’re not treating with curative intent and have many lines of therapy ahead of them. If we can delay more toxic therapy by as much as we can, that would only be a win for the patients.”

Patel R, Cascetta K, Klein P, et al. A multicenter, phase I/II trial of anastrozole, palbociclib, trastuzumab, and pertuzumab in hormone receptor (HR)-positive, HER2-positive metastatic breast cancer (ASPIRE). Presented at the 2023 San Antonio Breast Cancer Symposium; December 5-9, 2023; San Antonio, TX; abstract RF02-01.