The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) has approved Biogen’s QALSODY (tofersen), marking the first time a treatment specifically targeting a genetic cause of amyotrophic lateral sclerosis (ALS) has been authorised in the country.

The decision, made via the International Recognition Procedure (IRP), applies to adults living with ALS linked to mutations in the superoxide dismutase 1 (SOD1) gene, also known as SOD1-ALS. Tofersen was granted European Commission marketing authorisation under exceptional circumstances in May 2024.

SOD1-ALS is a devastating and uniformly fatal neurodegenerative condition. Individuals with ALS experience progressive muscle weakness, eventually losing the ability to move, speak, eat, and breathe. Despite extensive research over recent decades, few therapeutic advances have emerged due to the biological complexity and rarity of the disease, as well as a lack of reliable biomarkers.

Tofersen works by targeting the underlying genetic cause of the disease, and its approval is supported by clinical and biomarker data, including results from the Phase 3 VALOR study and its open-label extension. These data suggest that earlier treatment initiation may help slow progression in this ultra-rare form of ALS.

“This authorisation stands as both a major scientific achievement and a clear indication of the advances being made for those affected by this condition,” said Professor Ammar Al-Chalabi, professor of neurology and complex disease genetics at King’s College London. “Until now there have been no treatment options specifically for people with SOD1-ALS.”

The MHRA’s decision was welcomed by patient advocacy groups including MND Scotland, MND Association and My Name’5 Doddie Foundation, who described tofersen as a “genuine breakthrough” for patients with SOD1-ALS. “This is a significant milestone for the MND community,” they said in a joint statement. “It’s the first new treatment to receive marketing authorisation in the UK in almost 30 years.”

Tofersen’s development has also contributed to broader research efforts in ALS. Biogen has played a role in advancing neurofilament as an in vitro biomarker tool, potentially accelerating future trial designs in the field.

Dr Kylie Bromley, general manager of Biogen UK & Ireland, said: “We are incredibly proud to announce the MHRA approval of tofersen in the UK. This approval represents not only a significant scientific and regulatory achievement, but more importantly, a moment of real hope for the MND community.”

The company now faces the next challenge: securing NHS reimbursement for the therapy. Dr Bromley called on agencies including NICE, the Scottish Medicines Consortium (SMC) and NHS England to show flexibility in assessing rare disease treatments, noting that traditional cost-effectiveness thresholds often disadvantage therapies with limited data sets.

Biogen is engaging with regulators to ensure access to tofersen in other global markets. The treatment has already been approved in the US and EU.