Background:Phosphatidylinositol 3‐kinase (PI3K) inhibitors transformed management of various malignancies. This study preclinically characterized TQ‐B3525 (dual PI3Kα/δ inhibitor) and assessed the recommended phase 2 dose (RP2D), safety, efficacy, and pharmacokinetics in relapsed or refractory (R/R) lymphoma or advanced solid tumors (STs).
Methods:Oral TQ‐B3525 was given at eight dose levels on a 28‐day cycle. Primary end points were dose‐limiting toxicity (DLT), maximum tolerated dose (MTD), and safety.
Results:TQ‐B3525 showed high selectivity and suppressed tumor growth. Between June 12, 2018, and November 18, 2020, 80 patients were enrolled (63 in dose‐escalation cohort; 17 in dose‐expansion cohort). Two DLTs occurred in two (two of 63, 3.2%) DLT‐evaluable patients; MTD was not identified. TQ‐B3525 at 20 mg once daily was selected as RP2D. Grade 3 or worse treatment‐related adverse events mainly included hyperglycemia (16.3%), neutrophil count decreased (15.0%), and diarrhea (10.0%). Two (2.5%) treatment‐related deaths were reported. Sixty patients with R/R lymphoma and 11 advanced STs demonstrated objective response rates of 68.3% and 9.1%, disease control rates of 91.7% and 54.6%, median progression‐free survivals of 12.1 and 1.1 months; median overall survivals were not reached.
Conclusion:TQ‐B3525 exhibited rapid absorption and a nearly proportional increase in exposure. Acceptable safety and promising efficacy support further investigation of TQ‐B3525 (20 mg once daily) for R/R lymphoma.