SMA patients stick with Evrysdi for years, real-world study finds
People with spinal muscular atrophy (SMA) show high long-term adherence to treatment with Evrysdi (risdiplam), with several patients remaining on the oral therapy after three years, according to a real-world study in Spain.
The observational study, which involved adults and children with different SMA types, demonstrated that all patients adhered to treatment — a metric of the proportion of days covered during a certain period of time — with that measure at 100% at the one-year mark. Persistence, a different metric that accounts for the time to permanent discontinuation or switch, was also high years into treatment, the scientists noted.
“These findings suggest that [Evrysdi] is a practical long-term option in real-life settings, particularly because it can be taken at home,” the researchers wrote. “[The results] also highlight that continuing treatment over time may reflect how patients and clinicians perceive its benefits and risks in daily practice.”
The study, “Adherence, Persistence, and Safety of Risdiplam in Spinal Muscular Atrophy: A Population-Based Cohort Study,” was published in the journal Neurology and Therapy.
SMA is chiefly caused by mutations in the SMN1 gene that result in a deficiency of the SMN protein in the body. This leads to damage to motor neurons, the specialized nerve cells that control movement, and symptoms that include muscle weakness and wasting, fatigue, and breathing difficulties.
Marketed in the U.S. by Genentech, which was not involved in this study, Evrysdi is a disease-modifying therapy that targets the underlying cause of SMA. Specifically, its use allows more SMN protein to be produced by the SMN2 gene, a backup gene to SMN1.
The medication should be taken once daily, orally or via a feeding tube. Motor function benefits, along with a favorable safety profile, have been shown in clinical trials. Still, information remains scant on its use outside of trials.
“As [Evrysdi] becomes integrated into routine clinical practice, real-world data on adherence, persistence, and safety are essential to complement evidence from clinical trials,” the researchers wrote.
Study classified all patients as ‘fully adherent’ to Evrysdi use
To learn more, the team analyzed data from 53 individuals with SMA — 38 adults and 15 children, slightly more than half of them women and girls — treated with Evrysdi at the Hospital Universitari i Politècnic La Fe in Spain between 2020 and 2025. In this European nation, Evrysdi was first available under compassionate use in 2020 and became widely available under public reimbursement in 2023.
About half of the patients had SMA type 2, an intermediate form of the disease. Slightly more than 40% had type 3, a milder type, and about 6% had type 1, the condition’s most common form. Approximately one-third could not sit. In contrast, 13.2% — seven individuals — could walk.
Treatment was started at a median age of 36 in adults and 13 in children. One child with SMA type 1 began treatment before symptom onset. All took Evrysdi as an oral solution. Slightly more than one-third of the participants had been treated with Spinraza (nusinersen), another approved SMA therapy, for a median of 26 months, or slightly longer than two years.
Adherence to Evrysdi was high, with a proportion of days covered of 100% after one year, the data showed. The Morisky-Green questionnaire, a validated tool to assess medication-taking behavior — such as forgetfulness, carelessness, stopping treatment when feeling better, and stopping treatment if feeling worse — was available for 35 patients. All were classified as fully adherent.
Patients remained on treatment for a median of 28.1 months, or longer than two years. The vast majority of participants (93%) were taking Evrysdi after one year. In addition, persistence was higher than 80% at the two-year mark (87.8%) and at three years (80.1%), though the investigators stressed that these estimates should be taken with caution because the number of patients reaching later time points was limited.
These findings support the feasibility of [Evrysdi] as a long-term treatment option in routine clinical practice [and] highlight the value of population-based real-world studies in complementing clinical trial data.
Nine participants discontinued Evrysdi during the study: four due to lack or loss of clinical benefits, three due to adverse events, and one due to poor adherence. One patient decided to stop due to a lack of perceived benefit, despite the clinician’s recommendation to stay on therapy.
Four participants (8%) experienced adverse events, including diarrhea and fever in adults, and one case of leukocytoclastic vasculitis — a type of inflammation of small blood vessels — which prompted treatment discontinuation. That case was reported to the Spanish regulatory agency, and was incorporated as a post-marketing adverse drug reaction, the researchers noted.
According to the team, “these findings support the feasibility of [Evrysdi] as a long-term treatment option in routine clinical practice,” and “highlight the value of population-based real-world studies in complementing clinical trial data.”
In a plain-language summary, the researchers wrote: “We found that most patients took the medication consistently and continued treatment for prolonged periods.”
Still, the team noted that “additional long-term real-world evidence is needed to further characterize treatment durability and to inform individualized therapeutic decision-making.”
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