PIK3CA and breast cancer: In the phase 3 SOLAR-1 trial of alpelisib in patients with HR+/HER2− advanced breast cancer (ABC) and prior ET, progression-free survival with alpelisib plus fulvestrant was significantly prolonged compared with fulvestrant alone (median, 11.0 vs. 5.7 months; HR, 0.65; 95% CI, 0.50–0.85; P < 0.001 [PIK3CA-mutated]) [12].