Spinraza

Pharmaceutical company: Biogen

Spinraza is a small piece of man-made genetic material (called an antisense oligonucleotide). It targets the ‘back up’ SMN2 (survival motor neuron) gene so that it produces full-length, functional SMN protein. This protein is essential for the health of nerve cells which help to control muscles.

Spinraza comes as a liquid and is administered directly into the fluid around the spine and brain (cerebral spinal fluid) through an injection into the spine (lumbar puncture).

Spinraza has been recommended as a treatment option for people with spinal muscular atrophy in the UK. Please contact your (or child’s) clinical team for more information.

England, Wales and Northern Ireland

Read the full National Institute for Health and Care Excellence (NICE) guidance.

Scotland

Read the full Scottish Medicines Consortium (SMC) guidance, for type 1 and type 2 and 3. 

For over ten years the SMA community has tirelessly campaigned for access – we are proud to have worked alongside the community to ensure access. This involved working in partnership with charities SMA UK and Treat SMA, to ensure the experience and views of the SMA community were heard.

Spinraza has been tested in several clinical trials, including in babies and young children. In these trials Spinraza was found to be safe.

In the phase 3 ENDEAR trial, 122 infants with type 1 SMA aged under eight months were randomly assigned to receive Spinraza (81 participants) or placebo (dummy drug, 41 participants). The trial found that infants who received Spinraza had improved survival and motor function (measures of movement), compared to infants who received placebo. Over half (51%) of infants who received Spinraza reached a motor development milestone (such as rolling over, crawling), measured by the Hammersmith Infant Neurological Examination. None of the infants in the placebo group reached a motor milestone.

In the phase 3 CHERISH trial, 126 children aged between two and nine years, whose SMA symptoms started after six months of age took part in the trial. They were randomly assigned to receive Spinraza (84 participants) or placebo (dummy drug, 42 participants). After 15 months, children who received Spinraza showed improvements in completing activities related daily living, such as sitting, rolling and standing. This was measured by the Hammersmith Functional Motor Scale Expanded for SMA (HFMSE).  Over half (57%) of children who received Spinraza increased their HFMSE score by at least three points from the start of the trial to month 15, compared to 26% of children who received placebo.

Biogen has been studying a higher dose of Spinraza. This involves two starting doses of 50 mg given 14 days apart, followed by 28 mg every four months. Results from the Phase 2/3 DEVOTE trial suggest that, in children who hadn’t received treatment before, the higher dose helped improve movement compared to those who received a placebo (dummy drug) in an earlier Spinraza study. The trial also looked at children and adults who switched from the current dose to the higher dose, and their ability to move tended to improve after the switch.

Biogen has said they will now apply to the Medicines and Healthcare products Regulatory Agency (MHRA), who will decide whether the higher dose can be prescribed in the UK.

Last update: 15/05/2026