Biogen announces that the high dose regimen of Spinraza® (nusinersen), has been approved by the Medicines and Healthcare Products Regulatory Agency (MHRA) for the treatment of 5q spinal muscular atrophy (SMA).
The new high dose regimen comprises of a more rapid loading phase for naïve patients than the existing 12 mg regimen, with two 50 mg loading doses administered 14 days apart, and 28 mg maintenance dose injections every four months thereafter. Individuals transitioning from the 12 mg dose will receive one 50 mg dose in place of their next 12 mg dose, followed by 28 mg maintenance doses every four months thereafter.
SMA is a rare, genetic neuromuscular condition that affects approximately 1,600 infants, children and adults in the UK. Approximately 70 children are born with SMA each year in the UK.6 5q SMA is the most common form of the disease, representing approximately 95% of all SMA cases.7 It is caused by altered copies of a gene that prevent the body from producing enough SMN (Survival of Motor Neuron) protein. This leads to damage of motor neurons in the spinal cord; signals from the brain do not reach the muscles effectively, causing progressive muscle weakness and loss of movement. Although symptoms vary, SMA is distinct because of its specific genetic cause and pattern of progression.
The authorisation is based on data from the three-part, phase 2/3 devote study and its ongoing long-term extension, which assessed the high dose regimen of nusinersen in both treatment-naïve individuals and those previously treated with the 12 mg regimen.
In the devote study, reported adverse events were consistent with SMA and the known safety profile of nusinersen. No new safety concerns were observed with continued use of high dose nusinersen in the long-term-extension study. The most common adverse events that occurred in at least 10% of participants treated with the high dose regimen, and that occurred at least 5% more frequently than the matched sham group, were pneumonia, COVID-19, pneumonia aspiration, and malnutrition.
