Abstract
Purpose: :
Cis-retinoid replacement therapy effectively restored retinal function in Lrat-/- and Rpe65-/- murine models of certain forms of Leber’s congenital amaurosis (LCA) characterized by a deficiency in the vision chromophore 11-cis-retinal. The present study evaluated the proprietary cis-retinoid replacement therapy QLT091001 administered intravitreally in RPE65 null mutation dogs with congenital blindness comparable to human LCA.
Methods: :
QLT091001 in a vegetable oil (100 µL at 18%w/w) or neat (30 µL) was injected in the right eye and 4 weeks later in the left eye of three RPE65-/- 3-month old dogs, respectively. The dogs were kept in the dark for 3 days following each injection, whereafter scotopic and photopic simultaneously bilateral electroretinography (ERG) recordings were performed as well as clinical ophthalmic and behavioural studies at regular intervals before and up to 15 weeks after the first injection.
Results: :
In comparison to baseline studies, when the dogs were unwilling to move in the dark and bumped into objects in their way both in the dark and the light, follow-up studies showed obvious improvements in visual behaviour and marked improvement in ERG responses in both treated eyes. The functional improvement was preserved up to 7 weeks after the last intravitreal injection for 2 dogs and up to 11 weeks after the last intravitreal injection for the third dog. No treatment or drug related adverse effects were observed during the study period.
Conclusions: :
Intravitreal cis-retinoid replacement therapy caused a marked improvement in visual function in dogs with LCA-like disease, with no observed adverse effects.
Keywords: retinal degenerations: hereditary • retinoids/retinoid binding proteins • electroretinography: non-clinical