Background: Despite the success of recently introduced immunomodulatory therapies, multiple sclerosis and its ophthalmic manifestation as optic neuritis lead to irreversible axonal degeneration. Hence, it would be desirable to apply a neuroprotective therapy in parallel.
Results and discussion: We identified erythropoietin as an available and approved drug exerting neuroprotective effects in addition to its hematopoetic action. After several successful preclinical experiments, the pilot trial VISION PROTECT has shown that 33,000 IU erythropoietin, given intravenously on 3 consecutive days, preserves the retinal nerve fibre layer to a significant extent. This therapy will now be evaluated in a full scale and adequately powered trial to challenge this hypothesis. The TONE trial (Treatment of Optic Neuritis with Erythropoietin, NCT01962571) is a multicentric, prospective, double-blinded, clinical trial evaluating the same therapeutic regimen primarily with regard to thickness of the retinal nerve fibre layer and low contrast visual acuity.