Oral Metformin for Treatment of ABCA4 Retinopathy

Description

Study Description:

ABCA4 retinopathy is an autosomal recessive progressive retinal dystrophy that leads to retinal pigment epithelium (RPE) and photoreceptor degeneration, with consequent central visual loss. A treatment that either reduces the rate of lipofuscin accumulation or improves the clearance of lipofuscin in the RPE could potentially slow the degeneration associated with this disease. Metformin hydrochloride is a well-characterized, commonly prescribed oral anti-diabetic medication that acts by suppressing liver gluconeogenesis and increasing peripheral insulin sensitivity.

An additional effect of metformin is to increase macroautophagy via the Mammalian target of rapamycin complex 1 (mTORC1)/AMP-activated Kinase (AMPK) pathway; stimulation of this pathway would be predicted to enable the RPE to more efficiently handle lipofuscin. This suggests an association between metformin use and slowing of retinal degeneration. The objective of this study is to investigate the safety and potential efficacy of oral metformin in slowing the rate of change in photoreceptor degeneration in ABCA4 retinopathy.

Objectives:

The objective of this study is to investigate the safety and potential efficacy of oral metformin in slowing the rate of change in photoreceptor degeneration in ABCA4 retinopathy.

Endpoints:

Primary Endpoint: The difference in growth rate of square-root transformed area of EZ band loss (square-root AreaEZloss), from OCT, between the pre-treatment phase and 24 month metformin treatment phase.

Secondary Endpoints: Proportion of participants with a 30% reduction in growth rate of square-root AreaEZloss during the treatment phase compared to the pre-treatment phase, changes from baseline to Month 24 in Best-Corrected Visual Acuity (BCVA) total letters read, perimetry, and color fundus photography measurements and the change in rate of area of atrophy enlargement between the pre-treatment and 24-month metformin treatment phase.