By Jai S. Perumal, MD

Assistant Professor of Neurology, Weill Cornell Medical College

Dr. Perumal receives grant/research support from Genzyme Corp., and is on the speakers bureau for Biogen Idec, Teva Pharmaceuticals, Genzyme Corp., and Acorda Therapeutics.

SYNOPSIS: In a retrospective analysis of 871 relapses in 185 patients with neuromyelitis optica (NMO) or an NMO spectrum disorder, the authors reported that more than 80% of patients will have a partial or complete remission from their initial course of therapy.

SOURCE: Kleiter I, et al. Neuromyelitis optica: Evaluation of 871 attacks and 1153 treatment courses. Ann Neurol 2015; DOI: 10.1002/ana.24554.

Neuromyelitis optica (NMO) is an inflammatory disease of the central nervous system that preferentially affects the optic nerves and spinal cord. Classic NMO or Devic's disease is characterized by concurrent episodes of optic neuritis (ON) and transverse myelitis (TM). NMO spectrum disorder (NMOSD) is diagnosed in patients with isolated ON or TM who have the NMO IgG antibody, which is potentially pathogenic and has high specificity for this group of diseases. Unlike multiple sclerosis, the relapses in NMO tend to be more severe and show less recovery, often with residual deficits. Another feature of NMO that appears to be different from multiple sclerosis is that disability in NMO tends to accrue from residual deficits from relapses rather from a progressive phase. These distinguishing features make the recognition and treatment of relapses in NMO even more important.

In the present study, the authors conducted a retrospective analysis of 871 attacks in 185 patients whose data were captured in the Neuromyelits Optica Study Group (NEMOS) registry, which spans 16 tertiary referral centers and six regional hospitals in Germany. The primary objective measure was the short-term remission status post-relapse. The post-relapse remission status was categorized as complete recovery (CR) when there was full recovery, partial recovery (PR) when there was incomplete recovery, and no remission (NR) when there was no recovery at all.

They report the following findings:

  1. Frequency and Manifestation of Attacks: Episodes of isolated myelitis (59.4%) were more frequent than isolated optic neuritis (28.4%), simultaneous myelitis and optic neuritis (10.2%), or other presentations. Most of the episodes of optic neuritis tended to be unilateral rather than bilateral.
  2. Remission from Attacks: Regardless of the specific treatment modality, remission rates were significantly higher for isolated optic neuritis when compared to isolated myelitis or combined myelitis and optic neuritis.
  3. Treatment of Attacks: High-dose intravenous steroids (HD-S) was the most commonly used treatment (70.3%) and the next was plasmapheresis/immunoadsorption (PE/IA), which was used in 19.9% of the relapses. Less commonly used treatments included IVIG, intrathecal steroids, and low-dose steroids among others.
  4. Response to Treatment: First treatment resulted in CR in just 19.1%, PR in 64.5%, and NR in 16.4%. About a third of the attacks were treated with a second treatment course and a quarter of these were subsequently given a third course of treatment. Each escalation step significantly improved outcomes, with the second intervention having the greatest impact. PE/IA were superior to HD-S as first treatment for isolated myelitis but did not show significant difference when all attacks were pooled or in cases of optic neuritis or combined optic neuritis and myelitis.

COMMENTARY

The authors reported the results from their study of a large number of attacks in NMO/NMOSD patients. As has been reported previously, they demonstrated that recovery from attacks is not ideal, with myelitis and bilateral optic neuritis showing the worst outcomes. However, they show that escalation of therapy and treating patients with more than one treatment modality, especially a second treatment course, produces meaningful improvement in remission status. The limitations of this study include the retrospective nature of the analysis, potential bias that could have been introduced by factors that may have influenced the decision as to what treatment to offer to patients first, and the effect of concomitant disease-modifying therapies these patients may have been on that could have impacted severity and recovery from relapses. In conclusion, this large study corroborates findings previously reported on the severity and recovery from relapses in NMO. It demonstrates that an aggressive treatment approach utilizing more than one modality might be necessary to treat attacks in NMO.