A placebo-controlled trial of microplasmin intravitreous injection to facilitate posterior vitreous detachment before vitrectomy

Purpose: To evaluate the safety and efficacy of a preoperative intravitreous injection of microplasmin in patients scheduled for vitreous surgery.

Design: Phase 2, multicenter, placebo-controlled, double-masked, parallel-group, dose-ranging clinical trial.

Participants: One hundred twenty-five patients scheduled for pars plana vitrectomy (PPV), primarily for treatment of either vitreomacular traction or macular hole.

Intervention: A single intravitreous injection of either microplasmin at 1 of 3 doses (25 microg, 75 microg, or 125 microg in 100 microl) or placebo injection administered 7 days before PPV.

Main outcome measures: Presence or absence of posterior vitreous detachment (PVD) at the time of PPV, progression of PVD, and resolution of vitreomacular interface abnormality precluding the need for PPV.

Results: Rates of total PVD at the time of surgery were 10%, 14%, 18%, and 31% in the placebo group (n = 30), 25-microg (n = 29), 75-microg (n = 33), and 125-microg microplasmin groups (n = 32), respectively. The secondary end point resolution of vitreomacular interface abnormality precluding the need for vitrectomy at the 35-day time point was observed at rates of 3%, 10%, 15%, and 31% in the placebo, and the 25-microg, the 75-microg, and the 125-microg microplasmin groups, respectively. At the 180-day time point, the equivalent rates were 3%, 7%, 15%, and 28%, respectively.

Conclusions: Microplasmin injection at a dose of 125 microg led to a greater likelihood of induction and progression of PVD than placebo injection. Patients receiving microplasmin were significantly more likely not to require vitrectomy surgery. More definitive evaluation in phase 3 clinical trials therefore is warranted.

Financial disclosure(s): Proprietary or commercial disclosure may be found after the references.