First-in-human, first-in-class phase 1a study of BXQ-350 for solid tumors and gliomas.

2517Background: BXQ-350 is a novel agent composed of the multifunctional, lysosomal activator protein Saposin C and phosphatidylserine. BXQ-350 demonstrated antitumor effects in vitro and in vivo, particularly in glioma and pancreatic cancer models. Methods: A phase 1a dose-escalation trial (NCT02859857; Phase 1b ongoing) was conducted in refractory solid tumors/high-grade glioma (HGG) patients (Pt) by administering escalating IV BXQ-350 doses of 0.7, 1.1, 1.4, 1.8, or 2.4 mg/kg on days 1-5, 8, 10, 12, 15, 22 (cycle 1) and at 28-day cycles thereafter. Response was assessed at day 113 by RECIST or RANO. Results: 17 Pt (age 24-67) with a median 7 (range, 2-12) prior systemic therapies completed a median 2 (range, 1-6) cycles without DLTs or treatment-related serious adverse events (AEs). Moderately severe related AEs occurred in 3 (100%), 1 (33%), 1 (33%), and 2 (25%) Pt at 1.1, 1.4, 1.8, and 2.4 mg/kg cohort doses, respectively. The most common treatment-related AEs was transient fatigue (n = 4, 23.5%). At...