The Medicines and Healthcare Products Regulatory Agency (MHRA) has granted Biogen marketing authorisation for a high-dose regimen of nusinersen (marketed as Sprinraza) for those suffering from spinal muscular atrophy (SMA), a rare, genetic neuromuscular condition.
SMA affects approximately 1,600 infants, children and adults in the UK, and around 70 children are born with SMA each year in the UK.
The most common form of the disease is 5q SMA, which affects nearly 95 percent of all SMA cases.
The high-dose regimen (50/28 mg) of nusinersen has a more rapid loading phase for naïve patients (those taking the drug for the first time) than the existing 12 mg regimen.
In the high-dose regimen, two 50mg loading doses are administered 14 days apart, and 28mg maintenance dose injections every four months thereafter.
The study showed that treatment-naïve, symptomatic infants who received the high-dose regimen of nusinersen experienced significant improvements in motor function.
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 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 of the high dose regimen of nusinersen in the UK marks an important milestone for the SMA community,” said Kylie Bromley, General Manager and Managing Director, United Kingdom & Ireland, Biogen.
“Since Biogen secured the approval of the first treatment for SMA in the UK, we have worked hand-in-hand with clinicians and patient organisations to improve care and better meet the needs of people living with SMA.”
Giles Lomax, CEO at Spinal Muscular Atrophy UK welcomed approval of the high-dose regimen of nusinersen. "This decision ensures that people living with SMA continue to have access to treatment options that can adapt to their changing needs," she said.
