SMA, Duchenne muscular dystrophy and Pompe disease: Research highlights 2026 – No. 8
New studies have been published on a lower-cost generic version of Spinraza in SMA, two therapies discontinued in Duchenne muscular dystrophy and home-based enzyme replacement therapy in Pompe disease.
In SMA, a lower-cost generic version of Spinraza®
Available in France since 2017, Spinraza was the first approved treatment for 5q spinal muscular atrophy linked to SMN1. GNR-100 contains the same active substance – the antisense oligonucleotide nusinersen – and could become the first generic version of Spinraza. A generic medicine works in the same way as the original drug, whose patent has expired, with the same efficacy but at a lower cost.
A Russian team showed that this new product is equivalent to Spinraza: in patient-derived cells, it comparably increases production of the SMN protein, which is deficient in the disease. Clinical trials demonstrating its safety and efficacy led Russia and Kazakhstan to approve GNR-100 for marketing.
Two therapies definitively ruled out in Duchenne muscular dystrophy
- Results from the phase III TAMDMD trial of tamoxifen combined with corticosteroids had already shown a lack of short-term efficacy in Duchenne muscular dystrophy. The extension phase of the trial, which continued treatment for one additional year in 64 ambulant patients aged 7.5 to 13.9 years, confirmed these negative findings. Neither continuing treatment for an additional year nor earlier administration (patients treated in the first part of the study compared with placebo-group patients treated later) had any effect on disease progression or motor function.
- Published results from the CIFFREO trial involving 122 ambulant patients aged 4 to 8 years evaluating Pfizer’s microdystrophin gene therapy (fordadistrogene movaparvovec – PF06939926) also confirmed the lack of efficacy of this product in Duchenne muscular dystrophy. One year after treatment, no improvement in motor function was observed compared with the untreated placebo group. The benefit-risk profile of this gene therapy was considered unfavourable, notably due to serious adverse events reported in 25 of the 79 treated patients and in 5 of the 35 untreated patients. Preliminary data in this direction had already led to the discontinuation of the programme in July 2024.
- See the summary of the tamoxifen article and the summary of the CIFFREO trial article
Pompe disease: enzyme replacement therapy can be administered at home without increased risk
Treatment for late-onset glycogen storage disease type II (Pompe disease) is based on intravenous enzyme replacement therapy. Several therapeutic options are currently available: Myozyme©, Nexviadyme© (under early access) and, currently under clinical evaluation, cipaglucosidase alfa combined with miglustat.
Although administration is traditionally performed in hospital, home infusions have already been implemented for many patients. An analysis pooling data from three clinical trials involving 151 adults treated with cipaglucosidase alfa and miglustat compared the safety of hospital versus home administration. Of the 9,185 infusions, 22% were administered at home. The frequency of infusion-associated reactions was similar between home administration (1.3%) and hospital administration (1.8%). Fever was the most frequent adverse event at home (6.2% of patients), while in hospital the most common adverse events were headache (10.8%) and fever (6.2%). One patient treated at home experienced fever considered serious but was able to continue home treatment.
For patients without a history of moderate or severe adverse reactions, home treatment appears to be as safe as hospital administration while avoiding a four-hour hospital visit every two weeks.