Aldeyra Launches Phase 2 Clinical Trial of Methotrexate Intravitreal Injections for RP

The biotechnology company Aldeyra Therapeutics has launched a Phase 2 clinical trial of ADX-2191, an intravitreal injection of methotrexate, for people with autosomal dominant retinitis pigmentosa caused by the P23H mutation in the rhodopsin gene.

Taking place at Duke University Medical Center in Durham, North Carolina, the three-month trial will enroll eight patients. Four will receive monthly injections of ADX-2191. Four will receive injections of the emerging therapy twice each month. The trial will evaluate the safety and tolerability of ADX-2191. Aldeyra plans to report trial results in the second half of 2022.

Methotrexate is an FDA-approved treatment for certain types of cancer, severe psoriasis, or rheumatoid arthritis. The drug slows or stops the growth of cancer cells and suppresses the immune system.

The rhodopsin protein, when bound to a form of vitamin A called 11-cis-retinal, bestows light sensitivity to rod photoreceptors. The P23H mutation causes the rhodopsin protein to be misfolded, reducing its trafficking and function in rod photoreceptors. Ultimately, that leads to photoreceptor degeneration and vision loss. Lab studies have shown that methotrexate can improve the trafficking and function of the misfolded rhodopsin protein.