Phase I study of the pan-PI3K inhibitor buparlisib in adult Chinese patients with advanced solid tumors

Background/Aim: The phosphatidylinositol-3-kinase (PI3K) signaling pathway is frequently activated in cancer. Buparlisib (BKM120), an oral pan-PI3K inhibitor, inhibits proliferation of human cancer in preclinical models. Studies of buparlisib in Western and Japanese adults with advanced solid tumors established a recommended dose of 100 mg/day and showed an acceptable safety profile and evidence of efficacy. This phase I dose-escalation/expansion study aimed to establish the maximum tolerated dose (MTD) of single-agent, once daily oral buparlisib in Chinese patients with advanced solid tumors. Materials and Methods: Patients (n=32; primary tumor site: lung (n=15), breast (n=10) or head and neck (n=7); ≥2 prior lines of antineoplastic therapy (n=26)) received 80 mg (n=15) or 100 mg (n=17) daily buparlisib. Results: Five patients experienced dose-limiting toxicities: grade (G)3 depression (n=1), G2 hyperglycemia (n=3) and G3 hyperglycemia (n=1). Most frequent buparlisib-related adverse events were hyperglycemia (n=18; 56%), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) increase (n=9; 28%), as well as anxiety (n=6; 19%); most common buparlisib-related G3/4 adverse events: hyperglycemia (n=3; 9%), ALT and AST increase (n=2; 6%), as well as gamma-glutamyltransferase increase (n=2; 6%). Best response was stable disease (SD) in 10 patients (31%). Conclusion: The MTD of buparlisib was declared as 100 mg/day. Safety, efficacy and pharmacokinetic data from this study were similar to those previously reported in Western and Japanese populations.