Birch DG, et al. - Authors assessed the potential effectiveness and evaluated the safety of orally administered valproic acid (VPA) in the treatment of autosomal dominant retinitis pigmentosa. Compared to the placebo group, VPA arm had worse outcomes; as demonstrated by this negative value. The key methodological considerations that should be applied to the rigorous evaluation of treatments for these conditions were brought to light in the findings. The use of VPA in the treatment of autosomal dominant retinitis pigmentosa was not supported. This study does not provide support for the use of VPA in the treatment of autosomal dominant retinitis pigmentosa.

Methods

• Experts conducted a multicenter, phase 2, prospective, interventional, placebo-controlled, double-masked randomized clinical trial at 6 US academic retinal degeneration centers.
• They randomly assigned the individuals with genetically characterized autosomal dominant retinitis pigmentosa to receive treatment or placebo for 12 months.
• Intention-to-treat analyses were performed.
• They administered oral VPA 500 mg to 1000 mg daily for 12 months or placebo.
• Prior to study initiation, the primary outcome measure was determined as the change in visual field area (assessed by the III4e isopter, semiautomated kinetic perimetry) between baseline and month 12.

Results

• Findings suggested the mean (SD) age of the 90 participants was 50.4 (11.6) years.
• Findings suggested that 44 (48.9%) were women, 87 (96.7%) were white, and 79 (87.8%) were non-Hispanic.
• Results demonstrated that 79 participants (87.8%) completed the study (42 [95.5%] received placebo and 37 [80.4%] received VPA).
• A rhodopsin mutation was noted in 42 (46.7%).
• Nonetheless, 7 serious adverse events unrelated to VPA were reported most adverse events were mild.
• For mean change in the primary outcome the difference between the VPA and placebo arms was -150.43 degree2 (95% CI, -290.5 to -10.03; P = .035).