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Page last checked: 22nd November 2022
Last updated: 5th April 2017


In April 2017, the completed trial data indicated that what was then called AVXS-101 appeared to be safe and well tolerated by the young SMA Type 1 children being treated. Importantly, it also appeared to result in improved and sustained muscle function.

The trial included two different treatment strategies:

  • Cohort 1 were three infants aged 6-7 months (at the time of treatment) who were given a low virus dose, while
  • Cohort 2 included 12 infants aged 1-8 months and treated with a higher proposed therapeutic dose.

The following highlights from the trial were reported by what was then the pharmaceutical company AveXis (now Novartis Gene Therapies), which were accurate as of January 20th, 2017:

  • AVXS-101 continues to be well tolerated by patients, with no new treatment-related safety or tolerability concerns reported since the update in August 2016 (see below)


  • All 15 children in the trial remain event-free at 13.6 months of age. An event is defined as the time when ventilation support for breathing is required for at least 16 hours a day for 14 consecutive days, or sadly when a patient dies.


  • The muscle function of AVXS-101-treated patients is continuing to improve, as assessed by a test specifically developed to measure motor function of SMA Type I patients (The Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders – CHOP-INTEND).


  • The improvements in motor function are leading to patients consistently achieving and maintaining key developmental motor milestones. In cohort 2, 11/12 patients achieved head control and could sit with assistance, while 5/12 patients could even sit unassisted for 30 seconds or more.

Previous Updates

18th August: Avexis provides interim study results, accurate as of July 1st, 2016, shows in summary that:

  • AVXS-101 continues to be well tolerated by patients, with no new treatment-related adverse events.
  • Only one patient in Cohort 1 has reached a ventilation endpoint.
    The motor skills of AVXS-101-treated patients are continuing to improve.
  • 28th July: AVXS-101 receives “Breakthrough Therapy” status in the USA. This is when a drug designed to treat a serious disease, shows an early indication in clinical trials of being able to provide substantial benefit to patients.

23rd May: Previously known as scAAV9.CB.SMN and ChariSMA, the latest reported data of AVXS-101 drug shows that it continues to appear safe and well tolerated by the young SMA patients in the trial. Interim trial results:

8th January: Avexis completes Phase 1 patient enrolment

30th April: Avexis announces SMN1 Gene Therapy trial in the USA.