The Food and Drug Administration (FDA) has expanded the approval of Evrysdi® (risdiplam) to include infants less than 2 months of age with spinal muscular atrophy (SMA). Previously, the treatment was only approved for patients 2 months of age and older.

Evrysdi is a survival motor neuron-2 (SMN2) splicing modifier designed to treat patients with SMA caused by mutations in chromosome 5q that lead to SMN protein deficiency. The approval was based on efficacy and safety data from the open-label, single-arm phase 2 RAINBOWFISH study (ClinicalTrials.gov Identifier: NCT03779334), which evaluated Evrysdi in infants aged from birth to 6 weeks old (at first dose) with genetically diagnosed SMA who did not present with symptoms. At the time of interim analysis, there were a total of 18 enrolled patients, of which 7 were treated with Evrysdi for at least 12 months.

Interim results demonstrated that among the 6 patients with 2 or 3 copies of the SMN2 gene, treatment with Evrysdi was associated with the following motor milestones, as measured by Section 2 of the Hammersmith Infant Neurological Examination (HINE-2):  

  • Six (100%) patients achieved sitting (5 patients could pivot/rotate and 1 patient achieved stable sit).
  • Four (67%) patients could stand (3 patients could stand unaided and 1 patient could stand with support).
  • Three (50%) patients could walk independently.
  • All 6 patients were alive at 12 months without permanent ventilation.

The safety profile of Evrysdi was consistent with that observed in previous studies for symptomatic SMA patients. The most common adverse reactions reported were fever, diarrhea, and rash.

“The approval of Evrysdi for presymptomatic babies is particularly important, as early treatment of SMA, before symptoms start to arise, can help babies to achieve motor milestones,” said Richard Finkel, MD, RAINBOWFISH principal investigator and Director of the Experimental Neuroscience Program at St. Jude Children’s Research Hospital. “With the inclusion of SMA in newborn screening programs, this approval provides the opportunity to start treating at home with Evrysdi soon after the diagnosis is confirmed.”

The updated labeling also includes 2-year pooled data from Parts 1 and 2 of the phase 2/3 FIREFISH study (ClinicalTrials.gov Identifier: NCT02913482), which evaluated the long-term efficacy and safety in symptomatic infants 1 to 7 months of age with Type 1 SMA who received Evrysdi for 24 months (N=58). Results showed that 60% of infants were able to sit without support for 5 seconds and 40% were able to sit without support for 30 seconds. Additionally, 28% of patients achieved a standing measure (16% supporting weight and 12% standing with support) at 24 months.

Evrysdi is supplied in an amber glass bottle with two 6mL and two 12mL reusable oral syringes; each bottle contains 60mg of risdiplam and must be constituted by a health care provider prior to dispensing. Following constitution, the volume of solution is 80mL, providing 60mg/80mL (0.75mg/mL) risdiplam.

References

  1. FDA approves Genentech’s Evrysdi (risdiplam) for use in babies under two months with spinal muscular atrophy (SMA). News release. Genentech. May 30, 2022. Accessed May 31, 2022. https://www.gene.com/media/press-releases/14955/2022-05-30/fda-approves-genentechs-evrysdi-risdipla
  2. FDA approves label extension for Evrysdi® for infants with spinal muscular atrophy under 2 months old. News release. PTC Therapeutics, Inc. Accessed May 31, 2022. https://www.prnewswire.com/news-releases/fda-approves-label-extension-for-evrysdi-for-infants-with-spinal-muscular-atrophy-under-2-months-old-301557524.html
  3. Evrysdi. Package insert. Genentech; 2022. Accessed May 31, 2022. https://www.gene.com/download/pdf/evrysdi_prescribing.pdf