Mycobacterium W administration for steroid resistant optic neuritis with long-term follow-up

We report the long-term safety and outcomes of off-label Mycobacterium W (Mw) administration in steroid resistant optic neuritis.

In a case series, six patients with documented idiopathic corticosteroid refractory unilateral optic neuritis were treated with immuvac (Mycobacterium W extract). The dose was repeated at three months. Outcomes measures included the best corrected visual acuity (BCVA), pupillary reaction, colour vision, visual field(VF) examination (when possible), fundus examination and photography, and visually evoked potential (VEP) testing. BCVA, pupillary reaction, and color vision were monitored immediately prior to steroid therapy on days 1 and 7 post-steroid therapy, pre-Mw administration (i.e., 30 days after the last dose of steroids had been completed) and post-Mw administration on days 1, 7, 30, 90, 120, and 180. VF, VEP, and fundus photography were performed immediately prior to steroid administration, 30 days after the last dose of steroids (i.e., immediately prior to Mw), and at days 30, 90,120 and, 180. The patients were assessed six-month intervals thereafter for visual acuity, colour vision, and visual fields.

There were five females and three males in the age range of 30-54 years. Minimum follow-up was five years. All patients showed improvement in visual acuity, colour vision, and pupillary reaction. The patients showed stable improvement. There was no recurrence of the disease and no adverse events till the end of the follow-up period.

Mw appears to be safe in the long term and to improve steroid resistant optic neuritis; future randomized clinical trials would help affirm this observation.