Objective:

To understand providers’ assessment of outcomes following disease-modifying therapy (DMT; onasemnogene abeparvovec or nusinersen monotherapy, or onasemnogene abeparvovec following nusinersen) in patients with spinal muscular atrophy (SMA).

Background:

DMTs including one-time gene therapy (onasemnogene abeparvovec) and ongoing intrathecal survival motor neuron-2 (SMN2) splicing modifier (nusinersen) are approved for treating patients with SMA and have dramatically improved prognoses. However, real-world outcome data remain limited.

Design/Methods:

United States providers who treated patients with SMA between 6–24 months of age completed an electronic survey evaluating their assessment of improvement (defined by gains in ≥1 of the following domains: motor functioning, mobility, bulbar function, pulmonary function). Results were summarized descriptively.

Results:

Among the 22 providers who responded, 13 have prescribed onasemnogene abeparvovec monotherapy to patients with SMA (n=30 patients); 15 have prescribed nusinersen monotherapy (n=54); and 13 have prescribed onasemnogene abeparvovec after nusinersen (n=19). Improvements were achieved in 83.3% of patients receiving onasemnogene abeparvovec monotherapy, 64.8% of patients receiving nusinersen monotherapy, and 68.4% of patients receiving onasemnogene abeparvovec after nusinersen. Mean time (months, ±standard deviation) to achieving improvements in patients receiving onasemnogene abeparvovec monotherapy, nusinersen monotherapy, and onasemnogene abeparvovec after nusinersen, respectively, was 1.8±1.1, 4.4±3, and 2.7±2 for motor functioning; 2.6±2.3, 6.5±4, and 4.2±3 for mobility; 2.4±2.0, 5.6±3.1, and 4.1±3.5 for bulbar function, and 2.1±1.2, 6±3.7, and 3.9±2.4 for pulmonary function.

Conclusions:

Findings from this provider survey indicate a majority of patients with SMA achieved improvements with DMT administered between 6–24 months of age. Mean time to reported improvement was shorter in patients receiving onasemnogene abeparvovec monotherapy compared with nusinersen monotherapy. Given inherent limitations of physician survey studies, additional research including patient-level data is needed to further assess these outcomes in this population.