The Study: The phase 3 SANDPIPER trial assessed efficacy of the PI3Ki taselisib for patients with hormone receptor (HR)-positive, HER2-negative, PI3K-mutant breast cancer refractory to aromatase inhibition. All 516 enrollees received fulvestrant with the 2:1 randomized addition of taselisib or placebo. The primary endpoint of progression-free survival (PFS) was improved from 5 → 7 months, mirroring previous results with another PI3Ki in triple-negative breast cancer. As expected, toxicity was less than desirable.
Bottom Line: Results from this trial add support to those from last year’s published BELLE-2 trial, namely that PI3K inhibition has activity in HR-positive breast cancer but not without side effects. Also, take a mental break from your morning grind with some real-life sandpipers. | Baselga, ASCO 2018