Opthea, a biopharmaceutical firm that develops drugs for eye diseases, has completed patient enrolment in the Phase IIa trial of OPT-302 for diabetic macular edema (DME).

The randomised, dose expansion study involves determining the safety and efficacy of OPT-302 when administered in combination with aflibercept (Eylea) for treating DME.

OPT-302 is a soluble form of vascular endothelial growth factor receptor 3 (VEGFR-3) that prevents the activity of VEGF-C and VEGF-D, proteins involved in vessel growth and leakage in the eye.

The combination of OPT-302 and a VEGF-A inhibitor has shown potential to improve clinical outcomes in DME patients.

Around two million people globally are affected by DME, which is one of the major causes of vision loss among the working-age population.

Opthea CEO Dr Megan Baldwin said: “We are excited about the potential for OPT-302 in DME given the positive outcomes of our Phase IIb wet AMD study, as well as our earlier positive Phase Ib clinical results which showed dose escalation of OPT-302 combination therapy was well tolerated with improved visual and anatomic outcomes in patients with treatment-resistant and persistent DME.

“The ongoing Phase IIa DME study is further evaluating OPT-302 combination therapy in a larger patient population to confirm these observations and we look forward to reporting topline data in the second quarter of 2020.”

The Phase IIa trial is designed to feature around 108 patients with persistent centre-involved DME undergoing regular anti-VEGF-A monotherapy.

Subjects will be treated with either aflibercept (2 mg) + OPT-302 (2 mg) or aflibercept monotherapy.

The primary endpoint of the study is the proportion of patients receiving a combination of OPT-302 and aflibercept, showing a five letter gain in visual acuity from baseline at week 12.

Secondary endpoints include mean visual acuity, macular thickness, improvement in diabetic retinopathy severity score and durability of response.