Background
SMA is a genetic neuromuscular disease characterized by progressive muscle weakness. Three SMA disease-modifying therapies (DMTs) have been approved by the US FDA: nusinersen (SPINRAZA®), an intrathecally-administered SMN2-targeting antisense oligonucleotide, in 2016; onasemnogene abeparvovec (OA; ZOLGENSMA®), an intravenously-administered gene therapy designed to deliver a functional copy of the SMN1 gene to motor neurons, in 2019; and risdiplam (EVRYSDI®), an oral SMN2 pre-mRNA splicing modifier, in 2020. With the availability of DMTs, the disease course of SMA is changing. Despite this, there are limited real-world data available regarding SMA treatment patterns.
Objective
To examine real-world treatment patterns among individuals with SMA treated with a DMT.
Methods
This retrospective cohort study utilized administrative claims data from IQVIA PharMetrics® Plus, a US commercial claims database. Individuals who had ≥1 claim for an SMA DMT from January 2018 through December 2022 and ≥1 inpatient claim or ≥2 outpatient claims for an SMA diagnosis prior to the index date (date of first SMA DMT claim) were included. All individuals had ≥12 months of pre- and ≥30 days of post-index continuous enrollment in medical and pharmacy benefits; the pre-index requirement for individuals aged <1 year was ≥1 month. Post-index treatment patterns are reported.
Results
The cohort included 104 individuals. Median age at time of DMT initiation was 20 (range, 0-60) years and 54% (n=56) were female. Sixty individuals (58%) initiated treatment with nusinersen, 29 (28%) with risdiplam and 15 (14%) with OA. Most individuals received only one DMT (n=88 [85%]); 48 individuals (46%) received only nusinersen, 28 (27%) received only risdiplam and 12 (12%) received only OA. Of those who received >1 DMT (n=16 [15%]), nusinersen then risdiplam was the most common treatment sequence (n=8 [7.7%]).
Conclusions
This study provides an understanding of the evolving treatment landscape for individuals with SMA in US clinical practice.