Generating a PVD
Research has shown that the presence of a posterior vitreous detachment (PVD), where the vitreous is separated from the retina, may prevent growth of new blood vessels responsible for proliferative diabetic retinopathy (PDR).
ThromboGenics and its clinical advisors believe that using ocriplasmin to generate a PVD in patients with NPDR can prevent development of the new blood vessels that cause PDR, since they can no longer use the vitreous as a scaffold to grow along the retina's surface or into the vitreous.
Phase II CIRCLE study
ThromboGenics has started a phase II clinical study with THR-409 (ocriplasmin) and the first patient was enrolled in early 2016. The CIRCLE study is a randomized, double-masked, sham-controlled, multi-center study to evaluate the efficacy and safety of up to 3 intravitreal injections of either 0.125mg or 0.0625mg of ocriplasmin in subjects with moderately to very severe non-proliferative diabetic retinopathy (NPDR). The goal is to induce total PVD to reduce the risk of the patient developing sight-threatening PDR.
More than 200 subjects will be recruited from across the US, Canada, Europe, Middle East and Africa. The main endpoint of the CIRCLE study is the percentage of patients with total PVD by the month 3 visit, confirmed by both B-scan ultrasound and SD-OCT. The first results are expected in the second half of 2017.