Phase 1b Dose Escalation Study of Sozinibercept Inhibition of Vascular Endothelial Growth Factors C and D With Aflibercept for Diabetic Macular Edema.

Abstract

Purpose: Sozinibercept inhibits vascular endothelial growth factors (VEGFs) C and D. This study evaluated outcomes following switching from anti-VEGF-A monotherapy to intravitreal injections of three dose levels of sozinibercept in combination with aflibercept in patients with diabetic macular edema (DME).

Methods: A phase 1b, open-label, multicenter dose-escalation study with a 24-week follow-up. Patients received 3 loading doses of aflibercept (2 mg) in combination with sozinibercept (0.3, 1, or 2 mg) once every 4 weeks and were followed through week 24. The primary endpoint was safety, and secondary endpoints included mean change from baseline in best-corrected visual acuity (BCVA) and anatomic changes on imaging.

Results: Nine patients received sozinibercept in combination with aflibercept after a mean (SD) of 6.3 (2.4) injections of previous anti-VEGF-A. Sozinibercept combination therapy was well tolerated with no dose-limiting toxicities. Mean change in BCVA at week 12 was +7.7 letters (95% confidence interval [CI], 2-13.3) from baseline (65 letters [SD 5.5]) with a dose response for increasing doses of sozinibercept. At week 12, central subfield thickness (CST) was decreased by -71 µm (95% CI, -117 to -26) from baseline (434 µm [SD 58]), and 6 of 9 (67%) patients had a ≥50% reduction in excess foveal thickness.

Conclusions: In prior-treated patients with center-involved DME, switching to sozinibercept in combination with aflibercept was well tolerated with improved visual and anatomic outcomes.

Translational relevance: This first-in-human study builds upon basic research by providing safety and preliminary efficacy of sozinibercept (anti-VEGF-C/-D) in combination with aflibercept for DME.