PIK3CA and head and neck squamous cell carcinoma: The addition of the pan-PI3K inhibitor PX-866 to docetaxel did not significantly improve the median PFS when compared to docetaxel alone in patients with R/M HNSCC (92 days; 95% CI, 46–119 vs. 82 days; 95% CI, 47–96; p = 0.42) or OS (263 days; 95% CI, 125–383 vs. 195 days; 95% CI, 121–NR; p = 0.62) [79].