Abstract
Purpose::
Microplasmin is a recombinant protein containing the active moiety of plasmin. Given a smaller size than plasmin, it might be capable of better diffusion through the vitreous. In vitro, and in vivo experiments have demonstrated the ability of this compound to induce a posterior hyaloid detachment and alteration of vitreous structure. This initial clinical trial was conducted to determine its safety and provide early efficacy profile.
Methods::
In a prospective, non-randomized study conducted in 4 clinical centers, patients were recruited for 6 treatment cohorts consisting of 10 patients per cohort. Tested doses were 25, 50, 75 and 125 µg of microplasmin. Depending on the cohort, injection was given 1 hour, 1 day or 7 days prior to vitrectomy. Patients with macular hole stage II and III, tractional DME, or macular traction syndromes requiring surgery were eligible.
Results::
Evidence of activity was noted in all cohorts but was more evident following prolonged exposure and at higher dose concentration except the highest dose. Side effects were limited: no retinal toxicity was noted on electrophysiology, no ocular inflammation, and minimal cataract formation (nuclear sclerosis) consistent with post-vitrectomy setting was observed 3 months following surgery. One patient developed a retinal detachment starting 2 hours after injection of microplasmin.
Conclusions::
Microplasmin is a very promising compound for pharmacologic vitreolysis. Its clinical safety and efficacy profile have so far been promising.
Clinical Trial::
www.clinicaltrials.gov 2005-07-21
Keywords: vitreous • vitreoretinal surgery • drug toxicity/drug effects