Fabrice André, MD, PhD
The addition of the PI3K inhibitor alpelisib to fulvestrant (Faslodex) demonstrated efficacy as a treatment for patients with hormone receptor (HR)–positive, HER2-negative metastatic breast cancer who harbor PIK3CA
, Andre, a professor of Medical Oncology at the Institut Gustave Roussy in Villejuif, France, discussed the SOLAR-1 findings and their impact on the breast cancer landscape.
OncLive: Please share some background of the SOLAR-1 trial.
: We know that patients with HR-positive, HER2-negative metastatic breast cancer present with poor outcomes. The median survival is usually around 40 months. We know the vast majority of these patients will have progressive disease after 2 years under endocrine therapy and CDK4/6 inhibition. Based on this, there is a need to develop new therapies to improve outcomes for these patients. We know that 40% present with PIK3CA
mutations. These genes respond to PI3K inhibition.
mutations and the second were patients without the mutations. The patients were randomized to fulvestrant plus placebo or fulvestrant plus alpelisib. The primary endpoint was PFS in patients with these mutations.
What were the data presented at the 2018 ESMO Congress?
The data we presented at this meeting showed that, in patients with PIK3CA
mutations, there was an improvement in PFS. For those without mutations, there was no signal of efficacy, confirming the PIK3CA
is an effective indication of who is sensitive to this treatment. In terms of safety profile, the drug has 2 main toxicities. One is hyperglycemia, with 36% presenting with this side effect. The other is rash—10% of patients had grade 3 rash.
What is the significance of the findings in this patient population?
For patients, it means they have 1 more line of therapy that provides 11 months of disease control. We know that the treatment strategy for patients with metastatic breast cancer is to sequence 1 treatment after the other. The goal is to increase the duration of disease control. This new therapy perfectly fits this strategy. These are clinically meaningful data.
What is the prevalence of genetic testing in breast cancer?
Until recently, genomic testing was really only used to drive patients to clinical trials. In Europe, genetic testing for breast cancer is done almost only in the context of clinical trials. If alpelisib is approved and becomes more mainstream, genetic testing is going to have be more prominent for these patients. We would have to implement this.
André F, Ciruelos EM, Rubovszky G, et al. Alpelisib (ALP) + fulvestrant (FUL) for advanced breast cancer (ABC): results of the phase 3 SOLAR-1 trial. In: Proceedings from the 2018 ESMO Congress; October 19-23, 2018; Munich, Germany. Abstract LBA3.
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