Efficacy of protein-free calf blood extract for mechanical corneal epithelial defects in human eyes

Abstract

To evaluate the clinical efficacy between protein-free calf blood extract eye drops and recombinant human epidermal growth factor (rhEGF) eye drops for mechanical corneal epithelial defects in human eyes. A multi-center, randomized and double-blind study with a parallel, positive-control designation was carried out from April to November in 2005 at Department of Ophthalmology, Eye Ear Nose and Throat Hospital of Fudan University, Xinhua Hospital of Shanghai Jiaotong University, the First Hospital of Zhejiang University, the Second Hospital of Zhejiang University and Qingdao Municipal Hospital. 240 patients (240 eyes) with confirmed diagnosis of corneal epithelial defects at that six hospitals were enrolled in this study and were randomly arranged into two groups in average. One group (120 eyes) were treated by 20% protein-free calf blood extract eye drops which was defined as the experimental group while the other (120 eyes) by 5000 IU/ml recombinant human epidermal growth factor (rhEGF) eye drops as the positive control group. The drug was delivered in both groups 4 times per day, one drop each time in the 14 days duration. The symptoms and signs were scored and the safety was evaluated on the pre-delivery day, the third post-delivery day (day 3), day 7 and day 14. The variants in the study were tested for the different efficacy and safety between the two drugs using non-inferiority test, paired t-test, Wilcoxon signed-rank test, chi-square test, continuity correction chi-square test, Fisher's exact probabilities, analysis of variance, Cochran-Mantel-Haenszel chi-square test and so on. The criterion for statistical significance was P < 0.05. There was no significant difference in efficacy between the protein-free calf blood extract group and the recombinant human epidermal growth factor group (day 3: X2 = 1.5677, P = 0.4566, day 7: X2 = 1.7152, P = 0.4242, day 14: X2 = 3.0814, P = 0.2142). The total scores of symptoms and signs in experimental group had a obvious descending (6.009 +/- 3.030) compared with the positive control group with a descending of (5.177 +/- 2.582), which reached the significant level (t = 2.2367, P = 0.0263). Ocular local stimulates and general side effect were not observed within the treatment course. There was no significant difference between the two groups in the comparison of pre- and post-therapy visual acuity. The difference was not significant when comparing the uncomfortable feelings, including eye burning and eye itching (eye burning: day 3: X2 = 0.4394, P = 0.932, day 7: X2 = 1.4710, P = 0.479,day 14: X2 = 2.1875, P= 0.335, and eye itching: day 3: X2 = 2.1045, P = 0.349, day 7: X2 = 2.0192, P = 0.364, day 14: X2= 0.6863, P = 0.407). And the positive control group gave priority to the experimental group in comfortability. A better comfortableness was reported in the protein-free calf blood extract group on the third day post-delivery (X2 = 6.626, P = 0.0100). However, no obvious difference was examined on day 7 and day 14 post-delivery. Protein-free calf blood extract eye drops has confirmed efficacy, good safety, quick effect and better comfortableness.