Gene Therapy Shows Promise Treating Spinal Muscular Atrophy

Researchers testing AVXS-101 gene therapy for the treatment of children with spinal muscular atrophy type 1 reported remarkable progress on the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) scale, especially for children treated at less than 3 months of age.

Furthermore, the phase 1 study results prompted researchers to call for updates to the CHOP-INTEND scale. They said adding more advanced items will measure progress in children who are reaching previously unanticipated motor function milestones. The untreated progression of spinal muscular atrophy type 1 (SMA1) is such that by 6 months, almost no patients with SMA1 score >40 points on CHOP-INTEND (maximum score 64).

“Infants with SMA type 1 never sit up unassisted,” said Linda Lowes, PhD, a researcher at the Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, Ohio, who presented the study results at the American Academy of Neurology Annual Meeting. “They continue to decline rapidly, and they can never get a [CHOP-INTEND] score over 40.”

Although all the patients showed noteworthy progress, the children treated at younger ages improved more quickly said Lowes. This included patients who had the lowest baseline scores. Lowes drew attention to 3 patients who entered the trial with CHOP-INTEND scores below 20. “All 3 of these children came to us on pain killers and palliative care,” said Lowes. “The children who were dosed early sat quite a bit better and more quickly because they were [treated] early.”

One child in particular made impressive progress that continued after the trial completion. “He was a sick little pumpkin and he was dosed early and is now standing with support.”

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