ERBB2 and breast cancer: In the phase III SANDPIPER trial of taselisib in combination with fulvestrant in HR-positive, HER2-negative, advanced breast cancer patients pretreated with AI also demonstrated modest clinic benefit with only 2 month PFS advantage in the taselisib arm (7.4 vs. 5.4 months, HR 0.7, 95% CI 0.56–0.89; p = 0.0037).