Patients received up to 3 doses of SPINRAZA in study CS2 and up to 4 doses in study CS12. The dosage (3 mg to 12 mg in CS2 and 12 mg in CS12) and administration schedule differed from the approved SPINRAZA regimen. The median interval between the last dose in CS2 and the first dose in CS12 was 319 days.1,2
Limitations of this study include that it was open-label with no internal control groups. Because the 28 patients received their first dose in CS2 and then transferred to the second phase, CS12, the interval time between studies ranged from ~7 to ~13 months. The dosing and administration schedule in these studies differed from the approved SPINRAZA regimen.1,3
1. Darras BT, Chiriboga CA, Iannaccone ST, et al; on behalf of the ISIS-396443-CS2/ISIS-396443-CS12 Study Groups. Nusinersen in later-onset spinal muscular atrophy: long-term results from the phase 1/2 studies [published online April 24, 2019]. Neurology. doi:10.1212/WNL.0000000000007527.
2. Data on file. Biogen, Cambridge, MA.