Tryptophan immunoadsorption (Tr-IA) led to the clinical stabilization of highly active neuromyelitis optica spectrum disorder (NMOSD) in 2 patients who did not respond to standard drug therapy. The treatment was also well tolerated as maintenance therapy. This is according to a study published in the journal Therapeutic Advances in Neurological Disorders

“Our results suggest that response to previous therapy is an important aspect of individualized NMOSD maintenance therapy,” the researchers concluded. “Select patients with NMOSD who had a high attack rate despite adequate immunotherapy and responded well to previous apheresis therapies are candidates for maintenance Tr-IA treatment.”

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Previous research has shown that IA can be efficient in treating NMOSD attacks. However, it is not known whether it can prevent attacks or the progression of the disease with long-term use.

Here, a team of researchers from Germany led by Ingo Kleiter, MD, conducted a case study to evaluate the safety and efficacy of maintenance therapy with IA to prevent the recurrence of NMOSD attacks in patients who do not respond to other immunotherapies.

The researchers retrospectively analyzed 2 patients with severe refractory NMOSD. Both patients were treated with Tr-IA as attack therapy and responded well. They were then given Tr-IA twice a week as maintenance therapy.

The first patient had a yearly rate of NMOSD attacks of 1.38 in the last 10 years before starting regular Tr-IA therapy. Following the start of maintenance therapy with Tr-IA, she had just 1 mild attack in the last 3 years, which was resolved with steroid pulse therapy. Her Expanded Disability Status Scale (EDSS) score was stable at 5, and the visual function score of her affected eye improved from 3 to 1. 

The second patient had a yearly rate of NMOSD attacks of 1.7, consisting mainly of acute myelitis and optic neuritis in the last 10 years before the initiation of Tr-IA therapy. She had no other attacks following the start of regular Tr-IA treatment, and she was clinically stable with no additional need for immunosuppressive treatment. Her EDSS score improved from 6 to 5, and her ambulation score from 7 to 1. 

Both patients tolerated Tr-IA therapy well, with no serious adverse events associated with long-term use.

More research is now necessary with a larger number of patients to confirm these findings, the researchers concluded.


Heigl F, Hettich R, Fassbender C, et al. Immunoadsorption as maintenance therapy for refractory neuromyelitis optica spectrum disorder. Ther Adv Neurol Disord. Published online February 6, 2023. doi:10.1177/17562864221150314