ESMO 2017: Neoadjuvant Combination Therapy With Taselisib and Letrozole in Early Breast Cancer
According to the phase II LORELEI trial, which was led by Cristina Saura, MD, PhD, of Vall d’Hebron University Hospital, Barcelona, the addition of taselisib to letrozole prior to surgery improved response in postmenopausal patients with estrogen receptor–positive/HER2-negative early breast cancer—and in a subset of women with PIK3CA-mutant tumors. These findings were presented at the 2017 European Society for Medical Oncology (ESMO) Congress (Abstract LBA10_PR) in Madrid.
“We were able to detect a reduction in tumor size after only 16 weeks of treatment [with taselisib and letrozole], compared to patients who received letrozole plus placebo,” commented Dr. Saura in an ESMO press release. “The main message is that even though all patients seem to derive some benefit from taselisib, those who had this mutation [PIK3CA] seemed to derive more benefit.”
From 90 sites worldwide, 334 postmenopausal patients with estrogen–receptor positive/HER2-negative, stage I to III, operable early breast cancer took part in the trial. They were randomized to receive letrozole in combination with the oral PI3-kinase inhibitor taselisib or placebo.
The objective response rate was better with taselisib than placebo (50% vs. 39%). The 152 patients who had PIK3CA-mutant cancer cells at baseline demonstrated particular improvement with the taselisib combination therapy compared with those who received placebo (56% vs. 38%). The most common grade 3/4 adverse events with taselisib included gastrointestinal disorders (7.8%), infections (4.8%), and skin/subcutaneous tissue disorders (4.8%).