OBJECTIVES

Nusinersen, approved for the treatment of spinal muscular atrophy (SMA) across all ages, is administered intrathecally at a dose of 12 mg. In the US label, the approved administration starts with 3 loading doses at 14-day intervals, and a 4th loading dose 30 days thereafter. A maintenance dose is then administered every 4 months. In this study, real-world adherence and treatment patterns of nusinersen using a large US Commercial and Medicaid claims database were examined.

METHODS

Patients with SMA treated with nusinersen from January 1, 2017 to June 30, 2020 were identified via medication and HCPCS codes in the IBM^® MarketScan^® Research Databases. Patients with complete information on the date of nusinersen initiation were identified. Number of administrations during a specified follow-up period and distribution of inter-dose intervals were calculated. The percentage of doses on time was determined using grace periods of 7 days for loading doses and 30 days for maintenance doses.

RESULTS

During the study, 295 patients receiving nusinersen were identified with mean age (range) of 18.0 years (0-63) and with mean (standard deviation) follow-up time of 15.3 (11.5) months. Of those patients with 13 months and 23 months follow-up, the median number of nusinersen administrations was 6 and 8, respectively, aligning with the expected number of administrations within the same follow-up period. The inter-dose intervals also aligned with the expected dosing schedule: median (Q1-Q3) days from the previous dose were 14 (14-28) for the second and third doses, 30 (28-35) for the fourth dose, and 124 (118-130) for the maintenance doses (dose 5-11). Of the 1490 total doses administered during the study period, 1253 (84.1%) were administered on time.

CONCLUSIONS

In a real-world sample from a large US administrative claims dataset, the vast majority of patients with SMA received nusinersen according to the dosing schedule.