Investigating the neuroprotective effect of Copolymer-1 in acute primary angle closure - Interim report of a randomized placebo-controlled double-masked clinical trial.

To investigate the neuroprotective effect of Copolymer-1 (Cop-1) in patients with acute primary angle closure (APAC) in a randomized double-masked controlled trial. After initial medical management, APAC patients were randomized to receive either subcutaneous Cop-1 or placebo within 24 hr and at 1 week. After laser peripheral iridotomy (LPI), subjects underwent serial visual field (VF) tests and retinal nerve fibre layer (RNFL) thickness measurements with spectral-domain optical coherence tomography. The primary outcome measure was mean number of progressing points (significant slope of ≥ 1 dB per year sensitivity loss) over 16 weeks based on pointwise linear regression analysis, and the secondary outcome measure was the change in RNFL thickness. Thirty-eight patients (19 in each group) completed the study. Twenty-five (65.8%) were female, the majority being Chinese (86.8%) with mean age 62.5 years (SD 8.1). Patients in the Cop-1 group were found to have mean of 0.32 (SD 0.95) progressing points compared to 2.74 (SD 5.31) in the placebo group (p = 0.09), while 3/19 (15.8%) of Cop-1 treated patients had 1 or more progressing points compared to 7/19 (36.8%) in the placebo group (p = 0.14). There was no difference in change of RNFL thickness between groups (p = 0.57). We found improvement of mean deviation (MD) at week 16 in the Cop-1 group (p = 0.01) compared to worsening of MD in the placebo group (p = 0.04). After APAC, there was no difference in VF progression (or RNFL thickness change) between Cop-1 and placebo groups. However, there was improvement of MD in Cop-1 treated patients.