Therapeutic regimens and methods for improving visual function in visual disorders associated with an endogenous retinoid deficiency

Abstract

Therapeutic regimes for improving visual function in a subject having a deficiency in endogenously produced 11-cis retinal comprising administering the synthetic retinal derivative as a divided dose over 2-7 days then providing a resting period of 7-28 days after which the second dose of the synthetic retinal derivative is administered. Preferred synthetic retinal derivatives are 9-or 11-cis-retinyl esters. Disorders associated with deficiency in endogenously produced 11-cis retinal include retinitis pigmentosa and Leber congenital amaurosis

Description

RELATED APPLICATIONS[0001]This application is a continuation of U.S. application Ser. No. 14 / 382,235, filed Aug. 29, 2014, which is a national stage application under 35 U.S.C. §371 of International Application No. PCT / CA2013 / 050155, filed Mar. 1, 2013, which claims the benefit of priority to U.S. provisional patent application No. 61 / 605,729, filed Mar. 1, 2012; U.S. provisional patent application No. 61 / 642,212, filed May 3, 2012; and U.S. provisional patent application No. 61 / 644,360, filed May 8, 2012; the disclosures of which are incorporated herein by reference in their entirety.FIELD OF THE DISCLOSURE[0002]This disclosure is directed to therapeutic regimens and methods for improving visual function in a subject with a visual disorder associated with an endogenous retinoid deficiency comprising administering a synthetic retinal derivative to the subject.BACKGROUND[0003]Inherited retinal diseases (IRD) caused by gene mutations that disrupt or interfere with the production, conv...

AI Technical Summary

Benefits of technology

The present patent provides a method for improving vision in individuals with a deficiency in endogenously produced retinal components, such as in retinitis pigmentosa or Leber congenital amaurosis subjects. The method involves administering a therapeutic dose of a synthetic retinal derivative, followed by a resting period of less than one month, and then a second therapeutic dose of the retinyl ester after the resting period. The method is safe and well-tolerated, and can provide a meaningful improvement in visual function in subjects with these visual disorders.

Problems solved by technology

Inherited retinal diseases (IRD) caused by gene mutations that disrupt or interfere with the production, conversion and / or regeneration of 11-cis-retinal result in severe visual impairment and childhood blindness.

Endogenous retinoid deficiencies, such as those caused by mutations in the genes encoding the enzymes and proteins utilized in the visual cycle, impair the synthesis of 11-cis-retinal, the result of which leads to visual disorders due to the shortage or depletion of 11-cis-retinal.

There are a variety of forms of RP all of which show various limitations of visual performance over time and the course and progression of the disease show considerable variability between individuals.

These specific mutations, as well as mutations in ABCA4 and RDH12 are linked to defects in retinoid metabolism of the visual cycle and may result in photoreceptor degeneration.

Endogenous retinoid deficiencies, such as those caused by mutations in the genes encoding the enzymes and proteins utilized in the visual cycle impair the synthesis of 11-cis-retinal, the result of which leads to visual disorders due to the shortage or depletion of 11-cis-retinal.

Preclinical and clinical information show that loss of the function of the RPE65 protein blocks retinoid processing after esterification of vitamin A to membrane lipids and results in loss of vision.

Patients with LCA lack the ability to generate 11-cis-retinal in adequate quantities and therefore suffer from severe vision loss at birth, nystagmus, poor pupillary responses and severely diminished electroretinograms (ERGs).

Some forms of CSNB are due to a delay in the recycling of 11-cis-retinal.

Frequent administration of any retinoid to compensate for the bleaching effect implicates the well-known toxicity of the retinoid class of the compounds.

Toxicity caused by chronic administration of retinoids can cause changes in lipid metabolism, damage to the liver, nausea, vomiting, blurred vision, damage to bones, interference with bone development and several other serious undesirable effects.

This combination of a need for repeated administration in response to bleaching, and the undesirable serious side effects of repeated administration, poses a problem for the use of synthetic retinoids to improve visual function in a subject having an endogenous retinoid deficiency, such as RP or LCA.

A recent study evaluated the usefulness of retinoids as a treatment for these disorders and concluded that retinoids and similar compounds were not good therapeutic candidates.

Images