The UK’s National Institute for Health and Care Excellence (NICE) has not recommended Biogen’s Spinraza (nusinersen) for routine use by the National Health Service (NHS) to treat spinal muscular atrophy (SMA).

The decision was based upon uncertainties surrounding the drug’s long term effectiveness and its extremely high list price.

Clinical trial results indicated that nusinersen provided substantial clinical benefits to patients with SMA; however, NICE determined that the lack of long-term evidence meant uncertainties remained about the long-term benefits of the drug.

The regulator ruled that the two phase III clinical trials used for nusinersen’s approval had too short a follow-up period and Biogen’s modelling of long-term overall survival benefit were based on optimistic assumptions.

NICE concluded that even with a reduction of the US list price from £750,000 to £450,000 for the first year of treatment for UK patients, as well as a further proposed price reduction under an NHS patient access scheme, which remains confidential between NICE and Biogen, the price of the drug was too high to be considered cost-effective for the NHS.

The guidance refers to Biogen’s base-case incremental cost-effectiveness ratios (ICERs) for nusinersen, which when compared to standard care were £407,605 per quality-adjusted life year (QALY). The committee concluded that it would reasonable to assume the ICER may be in NICE’s cost-effective range between £400,000 and £600,000 per QALY; however, it was also possible it could be higher.

NICE director of the centre for health technology evaluation Meindert Boysen said: “The committee accepted that SMA is both rare and a very serious condition that can have a severe impact on people with it, as well as on family members and carers, and that there is an unmet need for effective treatments.

“The committee was willing to be flexible because of the nature of the condition and the paucity of the evidence, but the very high cost of nusinersen meant it could not recommend the drug as a cost effective use of NHS resources.

“Nusinersen is a promising treatment that has been shown to improve a range of outcomes important to patients. We are actively engaging with Biogen to discuss how they might address the uncertainties identified by the committee, while demonstrating the potential for nusinersen to be considered cost effective and managing the risk to the NHS of allowing access to this treatment.”

SMA is a genetic condition that affects nerves and the spinal cord. It causes muscle weakness, progressive movement and difficulty in breathing and swallowing. Nusinersen is the first treatment to address the underlying cause of the disease. Usually the condition is managed through supportive care that minimises the impact of the disability and improves patient’s quality of life.

NICE’s decision on nusinersen was announced in a draft guidance, which was made by the authority’s appraisal committee. The related public consultation will continue until 11 September and the second appraisal decision will be announced on 23 October this year.

The regulator remains hopeful of successful further discussions with Biogen over the pricing and its concerns about the long-term effectiveness of nusinersen.