Between June 2019 and June 2022, 95 children with treatment-naive type I SMA were identified in one of the 23 neuromuscular disease centres of reference. A study of ‘real-life’ data was carried out by a committee of French experts on 29 of these children, who were treated exclusively with Zolgensma®, with follow-up of at least one year:
- 22 with 2 copies of SMN2 and 7 with 3 copies of SMN2 ;
- treatment was administered at an average age of 7.5 months;
- two patients died as a result of thrombotic microangiopathy or respiratory distress;
- in the other 27 patients, motor scores (CHOP-INTEND and HINE-2) improved.
Of the 17 patients followed for two years :
- all were able to hold their heads,
- 15 were able to sit for 30 seconds without assistance,
- 12 were able to stand for a few seconds with assistance,
- 15 required an orthopaedic corset,
- three required ventilatory assistance,
- two required a gastrostomy,
- no further treatment was subsequently started because of continued motor improvement.
Concerning adverse events :
- 47% of patients followed for two years developed pneumonitis and 26% were hospitalised at least once for respiratory infections,
- Serious adverse events such as thrombotic microangiopathy need to be diagnosed early, through close biological monitoring over the first two weeks, so that treatment can be adapted quickly if necessary.
This real-life study shows favourable motor, respiratory and dietary outcomes in young patients treated before the onset of respiratory and bulbar dysfunction. However, a large proportion of patients developed spinal deformities.