OBJECTIVES: Spinal muscular atrophy type 1 (SMA1) is a rapidly progressing, debilitating disease, the genetic root cause of which is biallelic survival motor neuron 1 (SMN1) gene deletion/mutation, leading to subsequent motor neuron loss, muscle weakness, respiratory failure, and early death. Data on cost burden are limited and must be updated as the treatment landscape evolves. The first SMA treatment, nusinersen, was recently approved in the US (December 23, 2016) and EU (May 30, 2017). We undertook two retrospective claims analyses of real-world healthcare resource utilization (HRU) and costs among SMA1 patients.

METHODS: SMA1 patients ≤1-year old were identified and matched (1:1) with a random sample of infants in the QuintilesIMS PharMetrics Plus Health Plan Claims Database (US; February 2011–November 2016). SMA1 patients were identified in Symphony Health's Integrated Dataverse^® (US; September 2016–August 2018). HRU and costs were described in each database.

RESULTS: Significantly more SMA1 patients in PharMetrics (n=119) had ≥1 all-cause HRU claims vs. matched patients (98.3% vs. 54.6%, P<0.0001). Mean all-cause HRU and costs were higher for SMA1 infants; extrapolated all-cause total annual costs, based on month 1 post-diagnosis, were $324,751 (SMA1) vs. $3,294 (matched). SMA1 patients in Symphony (n=349, median follow-up of 7.9 months) had an average 59.4 days with medical visits/year (14.1 inpatient days; 13.5 days related to respiratory failure). In nusinersen-treated patients (n=45), those values were 56.6, 4.6, and 11.4 days following treatment initiation, respectively. Excluding nusinersen-related costs, mean healthcare costs per-patient-per-year were $137,627 (median: $43,167) for all patients and $92,618 (median: $29,425) for nusinersen-treated patients. Mean nusinersen-related costs were $191,909/month (median: $144,487) for the first 3 months (loading phase) and $36,882/month (median: $16,132) thereafter.

CONCLUSIONS: The economic burden of SMA1 is substantial, even among patients treated with nusinersen.