ESMO 2018: Targeting the Tumor Genome in Advanced Breast Cancer
Posted: Tuesday, November 13, 2018
According to the late-breaking results of the SOLAR-1 trial, the PI3K inhibitor alpelisib improved progression-free survival in some patients with advanced breast cancer. Fabrice André, MD, PhD, of the Institut Gustave Roussy, France, and colleagues, also noted a “manageable tolerability profile” for this new agent during their presentation at the European Society for Medical Oncology (ESMO) 2018 Congress in Munich (Abstract LBA3_PR).
“Alpelisib is the first drug to show a benefit in a genomic subgroup of breast cancer patients,” said Dr. André in an ESMO press release. “This study opens the door for clinical genomics for breast cancer as the first study to show that treatment based on a patient’s tumor genomic profile—specifically [the] PI3KCA mutation—can improve the outcome.”
In this phase III, international, randomized trial, 572 men and postmenopausal women with hormone receptor–positive, HER2-negative advanced breast cancer were enrolled. Patients had prior endocrine therapy but did not have prior chemotherapy. Of the 341 patients with PIK3CA mutations, half were randomly assigned to receive alpelisib and fulvestrant, and the other half received placebo and fulvestrant.
At a median follow-up of 20 months, patients receiving alpelisib had a median progression-free survival of 11.0 months, compared with 5.7 months in the placebo group. The overall response rate for patients with PIK3CA mutations treated with alpelisib and fulvestrant was 36%, compared with 16% for patients in the placebo group.
The toxicity profile of alpelisib and fulvestrant was reported to be manageable. Common side effects with the combination therapy were hyperglycemia, nausea, decreased appetite, and rash. A longer duration of follow-up is needed to determine whether the novel combination therapy confers long-term survival benefits.
