Treatment of diabetic macular edema with a designed ankyrin repeat protein that binds vascular endothelial growth factor: A phase I/II study

Purpose: To evaluate the safety and bioactivity of MP0112, a designed ankyrin repeat protein (DARPin) that specifically binds vascular endothelial growth factor (VEGF) in patients with diabetic macular edema (DME). DARPins are a novel class of proteins selected for specific, high-affinity binding to a target protein. Design: Phase I/II, open-label, multicenter dose-escalation trial. Methods: After a single intravitreal injection of MP0112, the main outcomes were safety assessments, aqueous MP0112 levels, change in best-corrected visual acuity (BCVA), and foveal thickness measured by optical coherence tomography. Six cohorts were planned, but only 3 were enrolled (0.04, 0.15, 0.4 mg), because a maximally tolerated dose of 1.0 mg was identified in a parallel age-related macular degeneration trial. Results: Median aqueous concentration of MP0112 was 555 nM 1 week and >10 nM in 3 of 4 patients 12 weeks post injection of 0.4 mg. Median BCVA improvement at week 12 was 4, 6, and 10 letters in cohorts 1, 2, and 3. Ocular inflammation was observed in 11 patients (61%) and was severe in 1. High-resolution chromatography separated proinflammatory impurities from MP0112, resulting in a new formulation. Conclusions: A single intraocular injection of 0.4 mg MP0112 resulted in levels above the half-maximal inhibitory concentration and neutralization of VEGF in aqueous humor for 8-12 weeks. Despite inflammation in several patients, there was prolonged edema reduction and improvement in vision in several patients. The source of the inflammation was eliminated from a new preparation that is being tested in an ongoing clinical trial.