5-FU, Heparin Does Not Prevent Postoperative Proliferative Vitreoretinopathy

Intravitreal 5-Fluorouracil (5-FU) and heparin does not appear to reduce the incidence of proliferative vitreoretinopathy (PVR) in eyes with primary rhegmatogenous retinal detachment (RRD), according to a study published in Ophthalmology. 

PVR is the principal cause of surgical failure following primary RRD. Currently, there is no proven treatment for preventing PVR. In a multicenter study, researchers compared the incidence of PVR in high-risk patients with primary RRD between 2 groups, those given 5-FU and low molecular weight heparin (LMWH) intravitreally, and those given a placebo.

The investigators evaluated PVR risk via non-invasive aqueous flare measurement using laser flare photometry. Patients were randomly assigned 1:1 to Verum (200mg/ml 5-FU and 5IU/ml Dalteparin) and a placebo (balanced salt solution) intravitreally applied during routine pars plana vitrectomy. 

The main endpoint was the development of PVR grade CP1 or higher (full-thickness retinal folds or subretinal strands in clock hours located posterior to equator) within 12 weeks after surgery. An endpoint committee examined fundus photographs for grading. Secondary endpoints consisted of PVR grade CA (A: located anterior to equator), best corrected visual acuity (BCVA) in logMAR, number and extent of surgeries to achieve retinal reattachment, and occurrence of drug-related adverse events within 12 weeks.

A total of 325 patients underwent the initial surgery and received 5-FU and LMWH (n=163) or placebo (n=162). The patients’ mean age was 65±10 years (74% men, 54% right eyes). The mean laser flare was 31±26 pc/ms. 

Researchers found no significant difference in PVR rate between the 2 groups. In all, postoperative failure occured in 83 total cases, ​​45 from the 5-FU and LMWH group (28%) and 38 from the placebo group (23%). They also found that none of the secondary endpoints were significantly different between the groups. 

From baseline to week 12, visual acuity showed a significant improvement in each group, but no difference were noted between them. No relevant safety risks were reported. 

Study limitations included that laser flare measurements were obtained from different models of flare meter and different examiners, and there were relatively high number of cases without adequate data for endpoint evaluation due to missing fundus photographs at the last visit.

“Altogether, we could not demonstrate a difference in incidence of PVR between treatment with intraoperative intravitreal 5-FU and LMWH and placebo treatment,” according to the researchers. 

Reference

Schaub F, Schiller P, Hoerster R, et al. Intravitreal 5-Fluorouracil and Heparin to Prevent Proliferative Vitreoretinopathy: results from a randomized clinical trial. Ophthalmol. Published online June 6, 2022. doi:10.1016/j.ophtha.2022.05.024