A phase I first-in-human study of REGN910 (SAR307746), a fully human and selective angiopoietin-2 (Ang2) monoclonal antibody (MAb), in patients with advanced solid tumor malignancies.

Abstract

2517 Background: REGN910 is a selective, fully human Ang2 MAb that potently blocks signaling through the Tie2 receptor regulating tumor angiogenesis and growth. In multiple mouse xenograft models of human solid tumors, REGN910 inhibits tumor growth. Methods: This first-in-human phase I study (3+3 design) explored the safety, recommended phase II dose (RP2D), pharmacokinetics (PK), pharmacodynamics (PD) and antitumor activity of REGN910 as a single agent. REGN910 was given IV at escalating doses. At RP2D, expansion cohorts were initiated to confirm safety and assess anti-tumor activity in about 20 patients (pts). Results: 37 pts [17M/20F; median age 57 (range 22-82); ECOG PS 0(9)/1(28)] were enrolled. Twenty-three (23) pts were enrolled in the dose escalation cohorts. No DLTs were reported, and a MTD was not reached. Most common G1/2 treatment-related adverse events (TRAEs) were fatigue 7(19%), peripheral edema 6(17%), diarrhea 5(14%), abdominal distension 4(11%), and decreased appetite 4(11%). There were no ≥ Grade 3 TRAEs. A confirmed sustained PR (16 wks) was observed in 1 pt with adrenocortical cancer treated at 1 mg/kg. SD (range 6.9-46.8 wks) was reported for 17 of 32 (53%) pts evaluable for efficacy. Fourteen pts received treatment >16 wks. One pt with thyroid cancer had SD for 46 wks, and 1 pt with hepatocellular cancer had SD for 16 wks with ≥50% decline in alpha-fetoprotein. Across all dose levels, REGN910 pharmacokinetics appeared linear and dose-proportional. The PK profile was characterized by an initial distribution and a single mono-exponential elimination phase. Total circulating serum Ang2 levels appeared saturated following treatment in all cohorts, indicating systemic target engagement at all doses tested. Conclusions: Administration of REGN910 in patients with advanced cancer is well tolerated, with generally mild and moderate TRAEs. Dose escalation is completed, and enrollment to the expansion cohorts continues. The safety profile supports combination with chemotherapy and/or other anti-angiogenic agents. Clinical trial information: NCT01271972.