Mino in ON

Treatment tested

• Minocycline

Other measures (1)

Inclusion Criteria: * Age between 18 and 60 years, the lower age limit has been set for safety purposes to avoid exposing children and adolescents to unproven therapies at least early in their development, the upper limit is set because the specificity of the diagnosis of ON is likely reduced in older individuals * onset of ON within the previous 30 days * intention to continue current multiple sclerosis (MS) disease modifying therapy (if any) for at least 6 months (glatiramer acetate, interferon beta) and not start, or switch to, a new therapy * sexually active participants of child-bearing potential must agree to use adequate contraception * willingness to provide written informed consent Exclusion Criteria: * Coexistence of any disease other than MS that could be responsible for ON or better explains their signs and symptoms. This would include patients with other suspected or established causes of vision loss including glaucoma, maculopathies, amblyopia, neuro-myelitis optica (NMO), and other optic neuropathies * clinically significant liver, renal, or bone marrow dysfunction * any condition that could interfere with any evaluation in the study including patients who are unable to undergo reliable OCT testing due to dense media opacities or severe nystagmus in whom appropriate fixation cannot be attained * concurrent or prior use of corticosteroids during this episode of optic neuritis * concurrent participation in any clinical therapeutic trial * use within the previous 12 months of any of the following: natalizumab, mitoxantrone, cyclophosphamide, azathioprine, cyclosporine, methotrexate, or any other immunomodulating or immunosuppressive drug including other recombinant or non-recombinant cytokine or any experimental therapy known to effect immune function * use within the previous 6 months of minocycline or another tetracycline or use of either for MS at any time * any other condition or situation that in the opinion of the investigator would either put the patient at risk of worsening health if enrolled in the trial or would prevent completion of the trial with complete follow-up.

The primary aim of this open-label pilot trial is to estimate the treatment effect of 100 mg of oral minocycline twice daily for 90 days, initiated within 30 days of onset of ON, on functional and structural optic nerve recovery compared to no treatment. The primary outcome measure that will be used to measure optic nerve recovery is retinal nerve fibre layer (RNFL) thickness. Other objectives: Secondary outcomes are temporal RNFL thickness, macular volume, and visual outcomes.