Eribulin Effective When Paired With Dual HER2 Blockade in BC

Eribulin seems to be an equally effective chemotherapy to pair with a dual HER2 blockade as taxane as first-line treatment for women with HER2-positive, locally advanced or metastatic breast cancer.

The results of this multicenter, randomized, open-label, parallel-group, phase 3 Japanese trial suggest that patients who cannot tolerate the standard taxane-based regimen have a new option for treatment.

“Our study is the first to show the non-inferiority of eribulin to a taxane, when used in combination with dual HER2 blockade as first-line treatment for this population,” lead author Toshinari Yamashita, MD, PhD, from the Kanagawa Cancer Center, in Kanagawa, Japan, said at the annual meeting of the American Society of Clinical Oncology (ASCO) 2024.

“To our knowledge, noninferiority of eribulin to a taxane when used in combination with dual HER2 blockade has not been investigated,” Dr Yamashita said.

“The combination of trastuzumab, pertuzumab, and taxane is a current standard first-line therapy for recurrent or metastatic HER2-positive breast cancer,” explained Dr Yamashita. “However, because of taxane-induced toxicity, the development of less toxic but equally effective alternatives are needed.”

“Because its efficacy is comparable to that of the current standard regimen, the combination of eribulin, trastuzumab, and pertuzumab is one of the options for first-line treatment of how to fight locally advanced or metastatic breast cancer,” he continued.

Study Results and Methods

The trial enrolled 446 patients, mean age 56 years, all of whom had locally advanced or metastatic breast cancer and no prior use of chemotherapy, excluding T-DM1. Patients who had received hormonal or HER2 therapy alone or the combination, as treatment for recurrence, were also eligible.

They were randomized 1:1 to receive a 21-day chemotherapy cycle of either (i) eribulin (1.4 mg/m² on days 1 and 8), or (ii) a taxane (docetaxel 75 mg/m² on day 1 or paclitaxel 80 mg/m² on days 1, 8 and 15), each being administered in combination with a dual HER2 blockade of trastuzumab plus pertuzumab.

Baseline characteristics of both groups were well balanced, with 257 (57.6%) having ER-positive disease, 292 (65.5%) visceral metastasis, and 263 (59%) with de novo stage 4 disease, explained Dr Yamashita.

For the primary endpoint, the median progression-free survival (PFS) was 14 versus 12.9 months in the eribulin and taxane group, respectively (hazard ratio [HR], 0.95, P = .6817), confirming non-inferiority of the study regimen, he reported.

The clinical benefit rate was similar between the two groups, with an objective response rate of 76.8% in the eribulin group and 75.2% in the taxane group.

Median OS was 65.3 months in the taxane group but has not been reached in the study group (HR, 1.09).

In terms of side-effects, the incidence of treatment-emergent adverse events was similar between the eribulin and taxane groups (58.9% vs 59.2%, respectively, for grade 3 or higher).

“Skin-related adverse events (62.4% vs 40.6%), diarrhea (54.1% vs 36.6%), and edema (42.2% vs 8.5%) tend to be more common with taxane, whereas neutropenia (61.6% vs 30.7%) and peripheral neuropathy (61.2% vs 52.8%) tend to be more common with eribulin use,” he said.

Overall, “these results suggest that eribulin is less toxic chemotherapeutic partner for dual HER2 blockade and can be used for a longer,” he said.

Findings Are a ‘Clinical Pearl’

Harold Burstein, MD, PhD, a breast cancer expert at Dana-Farber Cancer Institute and professor at Harvard Medical School in Boston, described the findings as “a nice clinical pearl,” because some patients do not tolerate taxane therapy. “In such cases, you can substitute eribulin, which is usually tolerated without allergic hypersensitivity issues,” he said in an interview.

Eribulin has specific properties that “could make it a perfect candidate” as an adjunct to standard treatment regimens across different breast cancer subtypes, observed Wynne Wijaya, MD an oncology researcher at the University of Oxford, England, and Universitas Gadjah Mada, in Yogyakarta, Indonesia, in a recent review (World J Exp Med. 2024;14[2]:92558).

Dr Wijaya, who was not involved in this study, said in an interview that the findings have important implications.

“This encouraging result adds eribulin as another option in the first line treatment regimen for patients with HER2-positive, locally advanced or metastatic breast cancer, especially in terms of side effects/toxicities,” she said. “As clinicians, we can offer to tailor the choice of therapy between eribulin versus taxane in the regimen based on [which side effects patients are better able to tolerate]. It would also be interesting and worthwhile to conduct similar trials in different types of populations to provide more robust evidence.”

Eisai Co. funded the research. Dr Yamashita disclosed ties with AstraZeneca, Chugai Pharmaceutical, Daiichi Sankyo, Eisai, Kyowa Hakko Kirin, Lilly, MSD, Pfizer, Taiho, Gilead Sciences, Nihonkayaku, Ono Yakuhin, and Seagen. Dr Burstein disclosed a research grant from National Cancer Institute. Dr Wijaya had no relevant disclosures.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.