Final Results Show PFS Benefit With Futibatinib for HR+ HER2– Breast Cancer

The phase 2 FOENIX-MBC2 trial (NCT04024436) demonstrated the efficacy of using futibatinib (TAS-120; Lytgobi) plus futibatinib and fulvestrant (Faslodex) as a treatment for patients with locally advanced/metastatic, hormone receptor–positive, HER2-negative breast cancer harboring FGFR gene amplifications, according to Senthil Damodaran, MD, PhD at the 2023 San Antonio Breast Cancer Symposium (SABCS).1

When speaking with CancerNetwork®, Damodaran, an assistant professor in the Department of Breast Medical Oncology at the University of Texas, MD Anderson Cancer Center, he discussed the regimen’s progression-free survival (PFS) benefit, with a median PFS of 7.2 months (95% CI, 2.1-7.6) among those who were treated.

Damodaran also spoke to the importance of specific biomarkers within this patient population.

Transcript:

This was a single arm study. We enrolled patients with hormone receptor–positive, metastatic breast cancers who had measurable disease and high copy number FGFR alterations. We combined futibatinib with fulvestrant. The primary end point of the study was 6-month PFS rate. The observed rate was about 52%, and the median PFS was about 7.2 months. Obviously, it's a small study. Because this is a genomically enriched study, we have to select the patient population, which takes time.

It showed promising activity. This is probably one of the few studies that have shown that targeting FGFR can lead to clinical outcomes. Of course, this needs to be confirmed in larger studies. We also want to look at specific biomarkers, and we want to see if there are other genomic alterations that can affect the way you respond to FGFR inhibitors. Oftentimes, you might see a ESR1 mutation or PIK3CA mutation on top of FGFR1, whether those coexisting mutations will affect response to FGFR targeting. That would be the next step.

Reference

Damodaran S, Turner N, Krop I, et al. RF01-04 Final results from the phase 2, open-label FOENIX-MBC2 study: efficacy and safety of futibatinib in adult patients with locally advanced/metastatic HR+/HER2− breast cancer harboring high-level FGFR1 gene amplification. Presented at the 2023 San Antonio Breast Cancer Symposium; December 5-9, 2023; San Antonio, TX. Abstract RF01-04.