A 58-year-old woman with genetically confirmed SOD1 mutation was diagnosed with ALS at the University of Miami in May 2023. Intrathecal Tofersen was started in July 2023 and she experienced stabilization of her respiratory decline and normalization of her neurofilament light chain (NfL) level.
Following 14th dose, she developed progressive sensorimotor deficits in her legs. She was diagnosed with myelitis after MRI showed multiple Gadolinium-enhancing lesions throughout the cervical and thoracic spinal cord. She received a single dose of intrathecal hydrocortisone 50 mg and intravenous methylprednisolone 1 g daily for 5 days, resulting in significant improvement in her sensorimotor symptoms.
Tofersen along with 50 mg intrathecal methylprednisolone was resumed 5 weeks after her last dose. However, her myelitis recurred, and she was treated with intravenous rituximab (two doses of 1000 mg, two weeks apart), which led to complete resolution of symptoms back to baseline. Tofersen was restarted in addition to a combination of intrathecal steroid and maintenance Rituximab, and she remains with normal NfL and without myelitis or significant ALS progression.