We collated the longitudinal data of children with SMA type 1 who received intravenous onasemongene abeparvovec (OA), from the SMAREACH database. 83 patients had baseline and at least one follow-up physiotherapy assessment with one of the five outcome measures of interest: CHOP-INTEND, HINE, RHS, RULM, and WHOM. We looked at the usage of non-invasive ventilation (NIV) in these children.
Median age at OA infusion was 0.78 years (range: 0.07 to 7.40 years); patients pre-treated with other disease modifying therapies (DMTs (54.2%)) were older (median 2.04 vs. 0.48 years). Duration of follow-up varied from 6-36 months; 74 patients had at least 12-month follow-up and 47 patients had at least 24-month follow-up. Weight at infusion ranged from 3.36-20.2 kg.
We had data for NIV-usage for 63 patients at baseline, 54 patients at 12-month follow-up and 28 patients at 24-month follow-up. The missing data includes those patients who were not due for 12 or 24-month follow-up. Median number of NIV dependent hours was 10/day; the duration ranged from 1-16 hours per day (IQR: 8–12 hours).
At baseline, 44/63 (70%) were not on NIV and 19/63 (30%) were. At 12-months follow-up 22/54 (41%) were not on NIV and 32/54 (59%) were. At 24-month follow-up, 15/28 (54%) were not on NIV and 13/28 (46%) were.
Available data from 63 patients with ≥2 valid NIV entries shows that NIV dependent hours increased in 17% (≥2 hours), stabilized in 30% (≥1 hour) and reduced in 40% (≥2 hours) and stopped in 13% of patients – this group had a higher proportion of patients with 3 copies of SMN2. Analysis of correlation between NIV usage and bulbar function in patients treated with OA is underway.