Phase I, Dose-Escalation Study of BKM120, an Oral Pan-Class I PI3K Inhibitor, in Patients With Advanced Solid Tumors

Overall, treatment was well tolerated. Dose-limiting toxicities were grade 2 mood alteration (80 mg), grade 3 epigastralgia, grade 3 rash, grade 2 and grade 3 mood alteration (100 mg), and two grade 4 hyperglycemia (150 mg). The MTD was 100 mg/d. Frequent treatment-related adverse events included rash, hyperglycemia, diarrhea, anorexia, and mood alteration (37% each); nausea (31%); fatigue (26%); pruritus (23%); and mucositis (23%). BKM120 demonstrated rapid absorption, half-life of ∼40 hours, ∼three-fold steady-state accumulation, dose-proportional exposure, and moderate interpatient variability. One patient demonstrated a confirmed partial response (triple-negative breast cancer); seven patients (20%) were on study for ≥ 8 months. BKM120 demonstrated dose-dependent pharmacodynamic effects on [(18)F]FDG-PET, fasting C-peptide, fasting blood glucose, and pS6. No significant trends were seen to correlate tumor molecular alterations with clinical activity.

This study demonstrates feasibility and proof-of-concept of class I PI3K inhibition in patients with advanced cancers. BKM120, at the MTD of 100 mg/d, is safe and well tolerated, with a favorable PK profile, clear evidence of target inhibition, and preliminary antitumor activity.