Two randomised, double-blind, pivotal phase III trials (n=652) investigated intravitreal injection of ocriplasmin versus placebo in patients with macular hole or vitreomacular traction syndrome. In both studies, non-surgical resolution of focal VMA (the primary endpoint) occurred one month after a single injection of ocriplasmin.
"The new data confirm the effectiveness of ocriplasmin in patients with VMA. This is important given that symptomatic VMA is implicated in a range of retinal disorders," said Dr Peter Kaiser, Professor of Ophthalmology at the Cleveland Clinic, Lerner College of Medicine, in the US.
In the study in patients with vitreomacular traction syndrome, a significantly larger proportion of patients had resolution of VMA and associated visual symptoms in the ocriplasmin group than in the placebo group (29.8% versus 7.7%; p=0.001).
In the other study, among patients with a full thickness macular hole (FTMH), 40.6% of those treated with ocriplasmin achieved closure compared with 17% of those on placebo (p=0.004). In patients with FTMH under 250 micrometres, closure was observed in 58% of ocriplasmin-treated patients compared with 20% of patients receiving placebo.
Additionally, in both studies, the percentage of patients that had gained 3 or more lines in visual acuity after 6 months of treatment was around double in the treatment arm compared with the placebo arm.
Symptomatic VMA can lead to retinal distortion if left untreated. Invasive vitreoretinal procedures have been used but surgical complications, incomplete separation or vitreous removal and high cost have prompted investigation into a pharmacological approach. "I am confident that ocriplasmin will provide an effective and safe pharmacologic option which can be used to treat patients earlier," said Dr Kaiser.
Ocriplasmin (microplasmin) is a modified form of the endogenous protease plasmin. It is thought to act by degrading the fibronectin, laminin and type IV collagen fibres that adhere the vitreous to the retina, causing posterior vitreous detachment.
ThromboGenics recently announced that the EMA has accepted for review a Centralised Marketing Authorisation Application for ocriplasmin 2.5mg/ml solution for injection.