"This is the final readout of the FIREFISH study, which has provided a wealth of insights and data, helping to firmly establish Evrysdi as an important treatment option," said chief medical officer Levi Garraway. Evrysdi was first approved in 2020 to treat SMA in adults and children two months and older based on the FIREFISH and SUNFISH trials. The small molecule's label was expanded in 2022 to include infants under two months. Newly released results from the FIREFISH study extension showed that after five years of Evrysdi treatment, 91% of children with Type 1 SMA – the most severe, infantile-onset form – were alive, whereas historically these patients would not have been expected to survive past two years of age. Additionally, 81% were alive without needing permanent ventilation. The majority also achieved or maintained major motor milestones like sitting – 59% could do so without support for 30 seconds – as well as standing and walking. Beyond mobility gains, 96% of participants could swallow, while 80% could feed orally without a feeding tube. Safety data were also reassuring, with no treatment discontinuations due to adverse events and a 66% reduction in overall event rates between years one and five.
Industry observers see room for Evrysdi to stake its claim in the SMA space. In a recent investor note, Baird analysts highlighted the crowded but lucrative landscape, stating that "while progressive, fatal, ultra orphan diseases have often provided blockbuster opportunities for many individual products, the emergence of three highly effective treatments in such rapid succession should likely continue to lead to pressure on the first."
Spinraza was approved by the FDA in 2016, while Zolgensma entered the market over two years later. In 2023, Biogen's drug generated sales of $1.7 billion, while Evrysdi generated CHF 1.4 billion ($1.6 billion) and Novartis recorded $1.2 billion from Zolgensma. Baird analysts expect Spinraza's commercial dominance to face "moderate pressure" from Evrysdi going forward, but anticipate the Biogen drug will still add "a nice cash stream for the next decade." They also touted well-entrenched Spinraza as "one of the most effective drugs we have ever seen."