e13531 Background: BXQ-350 is composed of the multifunctional, lysosomal-activator protein Saposin C and phosphatidylserine lipid with demonstrated antitumor effects in vitro and in vivo. In this abstract we update the safety and pharmacokinetic (PK) profile based on an ongoing Phase 1 trial. Methods: BXQ-350 was administered in a Phase 1a dose-escalation trial (NCT02859857), and an ongoing Phase 1b trial (data cut off at max of 6 cycles, 01DEC2018) to refractory solid tumor/high-grade glioma patients (pts). In Phase 1a, pts received escalating IV BXQ-350 doses of 0.7, 1.1, 1.4, 1.8, or 2.4 mg/kg on days 1, 2, 3, 4, 5, 8, 10, 12, 15, 22 (cycle 1), 29 (cycle 2), and thereafter 28-day cycles. PK was assessed over a 24-hr period following the first dose. The Saposin C level was analyzed by ELISA and PK parameters were calculated using noncompartmental methods. Results: The 1a cohort of 18 pts (age 24-69) had a median of 3 cycles and 1b cohort of 20 pts (age 31-80) had median of 2 cycles with no treatment-related serious adverse events to date. Moderately severe related adverse events (AEs, n case, n events) are reported with serious non-related events. The most common treatment-related AE was fatigue (2 at dose 1.1, 2 at 1.8, 1 at 2.4mg/kg and 3 in 1b), at 2.4 mg/kg, 1 pt had moderate blood pressure elevation. Exposures in the 1.4 and 1.8 mg/kg cohorts were less than dose-proportional, likely due to higher clearance in those groups. The overall mean clearance and half-live values were 66.8 (mL/kg/h) and 4.03 h, respectively. Conclusions: BXQ-350 has had no serious related AEs during dose-escalation or in the on-going trial supporting a tolerable safety profile at 2.4 mg/kg. Clinical trial information: NCT02859857. [Table: see text]
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