Roche and PTC Therapeutics have achieved a significant regulatory milestone as the FDA extends the approval of Evrysdi (risdiplam) to include infants under two months of age with spinal muscular atrophy (SMA). This expansion allows for treatment across the full age spectrum, from newborns to adults, matching the reach of competing therapies in the market.
Clinical Trial Success Demonstrates Early Treatment Benefits
The approval is backed by compelling data from the open-label RAINBOWFISH study, which evaluated Evrysdi in pre-symptomatic infants from birth to six weeks old. The results showed remarkable progress in developmental milestones, with all six babies carrying 2 or 3 copies of the SMN2 gene achieving the ability to sit independently after one year of treatment. Furthermore, four of these infants developed the ability to stand, and half reached the milestone of walking independently.
Dr. Richard Finkel of St Jude Children's Research Hospital, the RAINBOWFISH lead investigator, emphasized the significance of early intervention: "The approval of Evrysdi for pre-symptomatic babies is particularly important, as early treatment of SMA, before symptoms start to arise, can help babies to achieve motor milestones."
Market Impact and Commercial Performance
Evrysdi has demonstrated strong market performance since its initial approval in 2020, with first-quarter sales nearly tripling to CHF 226 million ($235 million). The drug's success can be attributed to its competitive pricing strategy and the convenience of oral administration at home, contrasting with Spinraza's requirement for spinal cord injection.
Treatment Landscape and Competition
The SMA treatment market now features three major players, each with distinct characteristics:
- Evrysdi: An oral medication administered at home
- Spinraza (Biogen): Requires spinal cord injection, priced at $750,000 for the first year
- Zolgensma (Novartis): A one-time gene therapy with a $2.1 million price tag, currently the world's most expensive drug
Disease Impact and Treatment Implementation
SMA affects approximately 1 in 10,000 babies and, when left untreated, stands as the leading genetic cause of infant mortality. The inclusion of SMA in newborn screening programs, coupled with Evrysdi's new approval, enables immediate intervention following diagnosis, potentially improving outcomes for affected infants.
The expanded label also includes enhanced efficacy claims, noting that most symptomatic babies treated with Evrysdi for at least two years could maintain a seated position for a minimum of five seconds, further validating the drug's therapeutic value.
Stuart Peltz, PTC Therapeutics' chief executive, highlighted the treatment's impact: "Evrysdi treatment allowed almost all of the babies to achieve developmental milestones in a similar timeframe as infants who don't have SMA."
