Initial Results Promising in First LCA Patients Treated with Synthetic Retinoid
QLT Inc. (Vancouver, Canada) announced interim results from the first 3 patients enrolled in a phase 1b clinical proof-of-concept study of QLT091001 for the treatment of Leber congenital amaurosis (LCA), an inherited retinal disease that affects three out of 100,000 births. QLT091001 is an orally administered synthetic retinoid replacement for 11-cis-retinal.
Three patients, 10, 12, and 38 years of age, all of whom have a genetic mutation in LRAT, have been enrolled and treated to date. After 7 days of treatment with QLT091001, all of the patients experienced clinically relevant improvements in one or more visual function parameters, including BCVA, Goldmann visual field, and/or retinal sensitivity as measured by full-field sensitivity threshold testing. The patients also reported meaningful improvements in their visual performance related to tasks of daily living. The onset of visual changes was rapid, and there was progressive improvement beyond the 7 days of treatment, with some effects persisting for up to 4 months after treatment was completed, according to the company.
The Phase 1b trial is a short-term, open-label, single singlecenter study to evaluate the safety profile and effects on retinal function in eight pediatric subjects, aged 5 to 14 years, diagnosed with LCA due to inherited deficiency of retinal pigment epithelium protein 65 (RPE65) or lecithin:retinol acyltransferase (LRAT). Based on the positive results from the first two pediatric patients, a protocol exception was granted to also treat an adult patient, according to a company news release.
Patients received daily oral doses of QLT091001 for 7 days at the Montreal Children's Hospital at the McGill University Health Center. Efficacy assessments included several visual function parameters including BCVA and visual field testing.
“The drug was only administered for a week, and the fact that we’re seeing a benefit of this magnitude and that it persists for some period of time is pretty amazing,” Bob Butchofsky, Chief Executive Officer of QLT Inc., said in an interview with Retina Today. “We’re extremely excited. For these three patients, I can say with confidence, it’s been life-changing for them so far.”
The study is ongoing and will enroll additional patients, including those who have LCA due to mutations in RPE65. Because of the prolonged treatment effects, the study will also continue to gather longerterm follow-up data on these patients. Completion of the current trial is expected before the end of 2010, Mr. Butchofsky said.
“The real curiosity now is how do we adjust those doses so that we get additional improvement and maintain [the efficacy] in these patients,” Mr. Butchofsky said.