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Page last checked: 7th August 2023
Last updated: 7th August 2023


The latest results from the NURTURE trial of Spinraza (nusinersen) were published in July 2023 in the scientific journal Muscle & Nerve, confirming previously released findings that pre-symptomatic delivery of the SMN-boosting drug results in dramatic improvement in the prognosis of SMA.

Starting in May 2015, the phase 2, open-label trial aims to evaluate the safety and effectiveness of nusinersen in 25 pre-symptomatic newborns who, based on their genetics, are very likely to develop SMA (Type 1 or 2 considered most likely). All participants received their first dose of nusinersen before six weeks of age, and have either two (15 participants) or three (10 participants) copies of SMN2.

The latest NURTURE study results, analysed after five years of treatment, show that all participants are alive, are free from permanent ventilation and continue to maintain and achieve World Health Organisation (WHO) motor milestones.

Of particular significance, 23 out of the 25 children are able to walk independently and 22 out of the 25 achieved the maximum score on the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders. Moreover, average scores on the Hammersmith Functional Motor Scale – Expanded (HFMSE) have continued to improve over the duration of the study.

Children with three copies of SMN2 achieved all the expected WHO motor milestones, with all milestones, except for one in one child, achieved within a normal timeframe. All 15 children with two copies of SMN2 were able to sit without support (11 within normal timeframe) and stand with assistance (9 within normal timeframe), 14 achieved walking with assistance (6 within normal timeframe), and 13 were able to walk unaided (6 within normal timeframe).

Importantly, the trial continues to support that nusinersen is safe and well tolerated over this extended follow-up period.

These results continue to confirm the importance of early therapeutic intervention to achieve the best outcome for SMA. They also show that motor milestone achievement is greater in people with three copies of SMN2 compared to two copies.

The expected end date for the trial is early 2025, with treatment evaluation to continue up to eight years of age.

Further information

Clinical Trial. Gov Page >
Muscle & Nerve Publication >

  1. De Vivo DC, Bertini E, Swoboda KJ, et al. Nusinersen initiated in infants during the presymptomatic stage of spinal muscular atrophy: Interim efficacy and safety results from the Phase 2 NURTURE study. Neuromuscul Disord. 2019;29(11):842‐856. doi:10.1016/j.nmd.2019.09.007.



After up to 4.8 years of continuous treatment with nusinersen, 100 percent of children treated pre-symptomatically were alive, and none required permanent ventilation:

  • Children continued to maintain and make progressive gains in motor function compared to the natural history of the disease, with 96 percent now able to walk with assistance.
  • The study was recently extended to evaluate the longer-term efficacy and safety of nusinersen up to 8 years of age

Additional results from the updated interim analysis of February 2020 showed:

  • All study participants who were previously able to walk with assistance (92 percent) and walk independently (88 percent) maintained that ability over the 11 months since the last data cut.¹
  • Over the 11 months of follow-up, one child gained the ability to walk with assistance (increasing to 96 percent of all study participants) and also reached the maximum score on the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) scale, increasing the total number of study participants who achieved the maximum score to 21 of 25 (84 percent).

Children with two copies of SMN2 were able to score and advance on the Hammersmith Functional Motor Scale Expanded scale (HFMSE), which is atypical to the natural history of the disease.

Nusinersen was well-tolerated, with no new safety concerns identified over the extended follow-up period. No children had discontinued the study due to adverse events associated with treatment.


24th October: Study updates were presented at the Cure SMA Annual SMA Conference and atthe European Academy of Neurology (EAN). After up to 45.1 months of analysis, nusinersen continued to demonstrate efficacy and safety in comparison to the natural history of SMA.

10th May: Data presented at the American Academy of Neurology’s conference. All infants were able to sit without support, 88% could walk with assistance, while 77% could walk without assistance. All infants were alive, none required permanent ventilation and no new safety concerns were identified.


9th October: Biogen reported that all the participants were now 14 months or older and alive, with none requiring permanent ventilation. The majority of participants (22 out of 25 = 88%) were able to walk either with assistance or independently; all of the participants were able to sit without support.


25th April: Biogen presented results from the interim analysis stage at the annual American Academy of Neurology meeting (April 22nd-28th).