Fampridine-SR and Optic Neuritis Recovery

Optic Neuritis (ON) is a condition that occurs in approximately 50% of individuals with relapse remitting MS, and is the presenting event in 15-20% of patients who go on to develop MS. These ON events present with a decline in vision over several days with painful eye movements. The purpose of this study is to collect pilot data on the effect of Fampridine-SR on the recovery of visual function after demyelinating optic neuritis.Our team evaluated a person with ON who had incomplete recovery which was quite bothersome to her. After a one-month treatment course Fampridine SR,her visual functioning improved. Based on this case, we present a unique opportunity to evaluate the potential benefit of Fampridine-SR as a potential treatment for persons who do not fully recover from acute ON.

Optic Neuritis (ON) is a condition that occurs in approximately 50% of individuals with relapse remitting MS, and is the presenting event in 15-20% of patients who go on to develop MS. ON usually presents with a decline in vision over several days to weeks with painful eye movements.

Fampridine-SR is currently a Health Canada approved medication to treat walking impairment in persons with MS. Some small studies in the past have shown that Fampridine-SR may also have positive effects on visual functioning in those experiencing ON.

This study will aim to assess the effect of taking Fampridine-SR for 8 weeks in 20 MS patients with unresolved optic neuritis on measures of visual functioning, and to determine the best measures to use in a future large scale study. The results of this study will also be used to estimate how many participants we will need in the future large scale study.

Eligibility Criteria:
Inclusion Criteria:

* Have an MS diagnosis, any type
* Had an acute optic neuritis without full recovery which occurred ≥ one year ago
* Have a visual acuity in the affected of eye of ≥ 20/40 or

  1. Or ≥20 ms difference in VEP between eyes
  2. Or ≥ 120 ms VEP in the affected eye
* Have not received corticosteroids in the last thirty (30) days
* Medications that could potentially affect the VEP P100 amplitude or may cause drowsiness/difficulty with visual fixation are allowed if there has been no change in dose within 30 days of study enrollment or anytime during the study. These medications include:

  1. Benzodiazepines other than every night at bedtime
  2. Opioid and opiates other than every night at bedtime
  3. Cannabinoid products other than every night at bedtime
* Have given written informed consent prior to any study related procedure not part of normal medical care, with the understanding that consent may be withdrawn by the subject at any time without prejudice to his/her future medical care

Exclusion Criteria:

* Have another medical condition that could affect the visual outcomes, such as, but not limited to, diabetes retinopathy, glaucoma, cataracts, previous ocular trauma, amblyopia, and optic neuropathy not due to a demyelinating lesion
* Creatinine clearance ≤ 80 mL/min
* Has a history of seizures, with the exception of febrile seizure as an infant
* Taking a medicinal product that is an inhibitor of Organic Cation Transporter 2 (OCT-2)