Effect of Treating Acute Optic Neuritis With Bioequivalent Oral vs Intravenous Corticosteroids: A Randomized Clinical Trial.

Importance: Intravenous (IV) administration of corticosteroids is the standard of care in the treatment of acute optic neuritis. However, it is uncertain whether a bioequivalent dose of corticosteroid administered orally, which may be more cost-efficient and convenient for patients, is as effective as IV administration in the treatment of acute optic neuritis.

Objective: To determine whether recovery of vision following treatment of acute optic neuritis with a high-dose IV corticosteroid is superior to that with a bioequivalent dose of an oral corticosteroid.

Design, Setting, And Participants: This single-blind (participants unblinded) randomized clinical trial with 6-month follow-up was conducted at a single tertiary care center in London, Ontario, Canada. Participants were enrolled from March 2012 to May 2015, with the last participant's final visit occurring November 2015. Patients 18 to 64 years of age presenting within 14 days of acute optic neuritis onset, without any recovery at time of randomization and without history of optic neuritis in the same eye, were screened. Inclusion criteria included best-corrected visual acuity (BCVA) of 20/40 or worse and corticosteroids deemed required by treating physician. In total, 89 participants were screened; 64 were eligible, but 9 declined to participate. Thus, 55 participants were enrolled and randomized. Primary analysis was unadjusted and according to the intention-to-treat principle.

Interventions: Participants were randomized 1:1 to the IV methylprednisolone sodium succinate (1000-mg) or oral prednisone (1250-mg) group.

Main Outcomes And Measures: Primary outcome was recovery of the latency of the P100 component of the visual evoked potential at 6 months. Secondary outcomes were the P100 latency at 1 month and BCVA as assessed with Early Treatment Diabetic Retinopathy Study letter scores on the alphabet chart and scores on low-contrast letters at 1 and 6 months.

Results: Of 55 randomized participants, the final analyzed cohort comprised 23 participants in the IV and 22 in the oral treatment groups. The mean (SD) age of the cohort was 34.6 (9.5) years, and there were 28 women (62.2%). At 6 months' recovery, P100 latency in the IV group improved by 62.9 milliseconds (from a mean [SD] of 181.9 [53.6] to 119.0 [16.5] milliseconds), and the oral group improved by 66.7 milliseconds (from a mean [SD] of 200.5 [67.2] to 133.8 [31.5] milliseconds), with no significant difference between groups (P = .07). Similarly, no significant group difference was found in the mean P100 latency recovery at 1 month. For BCVA, recovery between the groups did not reach statistical significance at 1 month or 6 months. In addition, improvements in low-contrast (1.25% and 2.5%) BCVA were not significantly different between treatment groups at 1 or 6 months' recovery.

Conclusions And Relevance: This study finds that bioequivalent doses of oral corticosteroids may be used as an alternative to IV corticosteroids to treat acute optic neuritis.

Trial Registration: clinicaltrials.gov Identifier: NCT01524250.