Abstract
Purpose :
Results from a randomized, multicenter, masked, placebo-controlled clinical trial under FDA IAND 11-785 demonstrate that the topical aldose reductase inhibitor Kinostat® prevents diabetic cataracts and dry eye development in diabetic dogs. Since diabetic cataracts are linked to glycemic control, we demonstrate that differences in glycemic control did not adversely affect the clinical results.
Methods :
Newly diabetic dogs with no lens changes or equatorial vacuoles < 360o present were recruited with the development of cortical cataracts by 9 months as the endpoint. Veterinary ophthalmologists examined all dogs at 0, 1, 2, 3, 6 and 9 months and the dog owners administered the masked medications TID. Hyperglycemia was measured as FDA required fructosamine levels by IDEXX Laboratories at each visit. A generalized linear mixed effect model was generated from the fructosamine data to investigate the development of osmotic cataracts over time with a binomial distribution and logit link. In this model, the treatment group, fructosamine levels (as continuous), and time period were considered as fixed effects.
Results :
Fructosamine levels were not significantly different between the Kinostat® and placebo groups; however, Kinostat®-treated dogs were 85% less likely to develop cortical cataracts by 9 months. Overall average fructosamines (0, 1, 2, 3, 6 and 9 months) in the placebo group with no cataracts was 399 ± 17 compared to 419 ± 11 for the Kinostat® group. Fructosamines were 457 ± 22 for placebos with cataracts compared to 502 ± 23 for the Kinostat® group. Dogs developing osmotic cataracts had significantly higher (p=0.0002) fructosamine levels (479 ± 16) compared to those not developing cataracts (408 ± 10). Every 10 µmol/L increase in fructosamine in the placebo group increased cataract development by 7% at 9 months (p=0.013).
Conclusions :
The fructosamine data supports the premise that hyperglycemia is linked to diabetic cataracts. Kinostat® prevents diabetic cataracts by preventing the metabolism of excess glucose to sorbitol independent of hyperglycemia levels present.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.