Recent research shows the long-term benefits and safety of risdiplam (Evrysdi®) use in both infants and adults with spinal muscular atrophy (SMA) type 1.

A recent press release by Genentech shared new results from the FIREFISH study, which included 48 patients aged 1 to 7 months who were previously diagnosed with type 1 SMA. The study indicated that the vast majority (91%) of infants treated with risdiplam were still alive after 3 continuous years of treatment.

The most prevalent adverse event (AE) was pyrexia, seen in 60% of cases, followed by infections in the urinary tract (57%) and lungs (43%). Other less common reactions included constipation, nasopharyngitis, diarrhea, rhinitis, vomiting, and cough. Pneumonia was the most common serious AE, followed by respiratory distress, acute respiratory failure, and respiratory failure; regardless, these serious AEs showcased a reduction of 50% after the first year of treatment. 


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Moreover, the motor benefits of this drug also seemed to prevail over time since most patients improved their swallowing capacity, 75% were able to sit without support at 36 months, 81.25% could hold their heads upright, and some could even stand (22.91%) and walk (6.25%) with support. These findings are especially promising since most children with SMA never achieve these milestones.

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“These long-term results in babies treated with Evrysdi are very encouraging, with the vast majority improving or maintaining motor functions after three years,“ Levi Garraway, MD, PhD, Genentech’s chief medical officer and head of global product development, said. “Without treatment, they would typically not survive beyond two years of age.”

Significantly, hospitalizations decreased from 1.24 to 0.70 per patient in the first vs third year, respectively.

Risdiplam is a survival motor neuron 2 splicing modifier that aims to increase the concentration of survival motor neuron protein, which is markedly decreased in SMA due to a mutation in chromosome 5q. This approach seems to diminish the symptoms and increase overall survival in these patients. Its use in adults has been previously tested and is known to be safe; hence, these findings in infants suggest an important therapeutic approach in arguably the most vulnerable group with SMA.

Reference

New three-year data for Genentech’s Evrysdi (risdiplam) show long-term improvements in survival and motor milestones in babies with type 1 spinal muscular atrophy (SMA). News release. Genentech; April 29, 2022.