Futibatinib Shows Promise in Breast Cancer With FGFR1 Gene Amplifications

Senthil Damodaran, MD, PhD, assistant professor, Department of Breast Medical Oncology, Division of Cancer Medicine, the University of Texas MD Anderson Cancer Center, discusses data from a phase 2 trial (NCT04024436) of futibatinib (Lytgobi) in patients with metastatic HR-positive/HER2-negative breast cancer with FGFR1 amplification in which results were presented at the San Antonio Breast Cancer Symposium (SABCS) 2023.

In the signal-seeking study, 22 patients with an FGFR1 amplification were enrolled, all of whom had received prior CDK4/6 inhibitors and had progressed on other therapies.

The median progression-free survival was 7.2 months, and the overall clinical benefit rate was 50%. According to Damodaran, this efficacy is comparable with other targeted therapies that have been used for FGFR2 and FGFR3 mutations, and suggest the potential benefit of futibatinib in this space with further development.

0:09 | This was, in some sense, a signal-seeking study. So, we enrolled about 22 patients into the study. As mentioned before, all of them had FGFR1 amplification. Pretty much all of these patients had received prior CDK4/6 inhibitors, so this is essentially the second- or third-line. When we look at the patient population, almost all of them had received 2 median lines of therapy. We also allowed chemotherapy to be given in between.

0:37 | In this particular patient population, the median progression-free survival was about 7.2 months, and the 6-month PFS rate was about 51.6%. The response rate, and most of the responses were partial, at about 18%, and the overall clinical benefit rate was about 50%. Just to kind of give an idea, so for fulvestrant as a single agent, the progression-free survival is about 2 months. So, it's not that impressive. But we do have other targeted therapy agents like, for example, now we have capivasertib [Truqap] approved for PIK3CA and AKT1, [or PTEN] mutations. We also had alpelisib [Piqray] previously approved for PIK3CA mutations. In those studies, the observed PFS was very similar to what we saw here. That was around like 7 months. Of course, this is FGFR1, and those were FGFR2 and 3, but it seems very comparable in terms of efficacy.