5-fluorouracil plus heparin no better than placebo in preventing proliferative vitreoretinopathy

Adjuvant therapy with 5-fluorouracil and low-molecular weight heparin (LMWH) is not superior to placebo in the prevention of proliferative vitreoretinopathy (PVR) in eyes with rhegmatogenous retinal detachment (RRD), reports a study.

A total of 325 RRD patients who were at high risk for PVR were randomized to verum (200 mg/ml 5-FU and 5 IU/ml dalteparin; n=163) or placebo (balanced salt solution; n=162) applied intravitreally during routine pars plana vitrectomy. PVR risk was assessed by measuring the noninvasive aqueous flare using laser flare photometry.

The investigators applied a group sequential design with one interim analysis using the O’Brien and Fleming boundaries. They then compared proliferative vitreoretinopathy grade CP (full-thickness retinal folds or subretinal strands in clock hours located posterior to equator) incidence using a Mantel-Haenszel test stratified by surgeon.

Mean laser flare in study eyes was 31 pc/ms. PVR rates did not significantly differ between the two treatment groups.

Primary analysis in the modified intention-to-treat population results were 28 percent with verum and 23 percent with placebo, including not assessable cases as failure (odds ratio [OR], 1.25, 95 percent confidence interval [CI], 0.76‒2.08; p=0.77). In the per-protocol population, the rates were both 12 percent (OR, 1.05, 95 percent CI, 0.47‒2.34; p=0.47).

Best-corrected visual acuity and redetachment rate also did not show any significant differences between treatment groups. In addition, no relevant safety risks were observed during the study period.

“PVR is the major cause for surgical failure after primary RRD,” the investigators said. “So far, no therapy has been proven to prevent PVR.”