Satralizumab after inebilizumab treatment in a patient with recurrent neuromyelitis optica spectrum disorder: A case report

Abstract

Rationale: Neuromyelitis optica spectrum disorder (NMOSD) comprises a group of rare and severe autoimmune inflammatory diseases affecting the central nervous system, mainly the optic nerves and spinal cord. Phase III studies have shown that the incidence of relapse is significantly reduced in aquaporin (AQP) 4 antibody-positive patients after treatment with satralizumab, a humanized monoclonal recycling antibody that blocks interleukin (IL)-6 signaling pathways, in conjunction with inebilizumab, a B-cell-depleting agent. Here, we report our experience with a patient who presented with pain associated with NMOSD.

Patient concerns: A 40-year-old woman initially presented with acute thoracic myelitis. Magnetic resonance imaging revealed a demyelinating lesion in the spinal cord spanning from T2 to T10, along with enhancement and a positive serum AQP4-immunoglobulin G (IgG) titer.

Diagnosis: NMOSD.

Interventions: The patient initially received adequate long-term immunotherapy with inebilizumab and corticosteroids. Satralizumab was administered after treatment failure.

Outcomes: The patient experienced recurrences of the disorder despite the initial immunotherapy, including pain and immobility from neurological dysfunction. Furthermore, her serum AQP4-IgG titer remained elevated (1:320), her B-cell proportion remained at 0, and her symptoms were not adequately relieved. She was then administered satralizumab, after which her serum AQP4-IgG and IL-6 levels decreased, the radiological appearance of spinal cord demyelination improved, her pain and other symptoms were alleviated, and her neurological function gradually recovered.

Lessons: In patients with clinical episodes of NMOSD that recur despite treatment with a B-cell-depleting agent, satralizumab may help alleviate myelitis-associated pain. Further investigations are warranted to establish IL-6 as a therapeutic target for the treatment of neuropathic pain, and may help address the unmet medical need in the management of NMOSD-associated neuropathic pain. As exemplified by the present case, individualized management, and therapy for patients with NMOSD are essential. Our case report provides new ideas for the management of patients with refractory NMOSD and patients with subsequent severe neuropathic pain.

Keywords: immunotherapy; interleukin-6 receptor inhibitor; neuromyelitis optica spectrum disorders; satralizumab.

Figure 1.

Sagittal magnetic resonance images of the thoracic spine: T2-weighted and T1-weighted imaging with contrast. (A and B) A long demyelinating lesion exhibiting contrast enhancement is seen from T2 to T10, 2 months after her initial presentation. (C and D) Images 4 months later revealing demyelination from T4 to T8. (E and F) Images acquired almost 1 year after diagnosis revealing demyelination from T4 to T7.

Figure 2.

Back pain, as rated on the numerical rating scale from the time of diagnosis (January 2023) to the most recent follow-up (January 2024).

Figure 3.

Expanded Disability Status Scale scores over time after satralizumab administration was initiated.

Figure 4.

Timeline of laboratory and imaging findings and treatment. AQP4-IgG = aquaporin 4-immunoglobulin G; IVIG = intravenous immunoglobulin; OCS = oral corticosteroid.