Prof. Cintas of the Toulouse Neuromuscular Reference Centre published in December 2022 a review of new therapies for SMN1-related proximal spinal muscular atrophy (SMA) in adults. It shows that :
- more than 80% of adults with SMA consider that a treatment that stabilises the evolution of their disease constitutes an important therapeutic advance.
- For nusinersen (Spinraza®), 61-75% of adults report improvement and only 2.5-25% deterioration, with persistent effects for more than one year. The treatment is well tolerated and the lack of a dose escalation study in adults means that the approved treatment of 12mg per injection is the same for newborn babies as for adults; a study is underway to evaluate higher doses.
- For risdiplam (Evrisdy®), the SUNFISH trial, which involved participants aged 2 to 25 years, included only 14 participants aged 18 to 25 years, making interpretation of the results difficult. The approval of risdiplam for all types of SMA, including adults, should provide more real-life data on the safety and efficacy of this compound in adults.
- for the onasemnogenic abeparvovec (Zolgensma®) gene therapy, reserved for the youngest patients, the dose necessary for the treatment of children over 21 kg and a fortiori adults would expose to too strong allergic reactions
- For salbutamol, a randomised placebo-controlled trial in participants aged 25 to 53 years confirms increased inclusion of exon 7 in SMN2 with an improvement in the 6-minute walk test by 30 metres at one year. Salbutamol is approved for SMA on a compassionate access basis (CAA).
- For reldesemtiv, a fast troponin activator, a phase II trial in people with a mean age of 29.4 years showed encouraging results. Further studies are needed to confirm the value of this compound in SMA.
