Administering Spinraza (nusinersen) via a particular method of injection, called the paramedian approach, can shorten procedure times and reduce the occurrence of adverse events for people with spinal muscular atrophy (SMA), a small study suggests.
This method may prove to be a much easier route of administration for SMA patients with scoliosis and other spinal issues, the researchers said.
The study, “Administration of nusinersen via paramedian approach for spinal muscular atrophy,” was published in Brain & Development.
Spinraza, developed by Biogen, was the first disease-modifying therapy approved for treating SMA. It works by allowing the body to produce more of the survival motor neuron (SMN) protein, a protein that’s essential for the health of motor neurons and is present in lower amounts in people with SMA.
In order to work properly, Spinraza needs to be injected directly into the liquid that surrounds the brain and spinal cord, called the cerebrospinal fluid. This typically is achieved via intrathecal injection — an injection into the base of the spinal cord.
The most common strategy for intrathecal injections is known as the interspinous approach, but it can be difficult, especially in individuals with spinal complications like scoliosis, when the spine curves sideways.
“In patients with SMA, both scoliosis and lack of spinal flexibility can be a barrier for intrathecal nusinersen [Spinraza] administration,” the researchers wrote.
“Our first intrathecal administration of nusinersen was performed via classical interspinous approach. It was very difficult and necessitated multiple attempts and long procedure time, resulting in unbearable burden of the patient,” they wrote.
An alternative to the interspinous approach is the paramedian approach — the difference between the two has to do with how the needle is inserted through the spine, in terms of position and angle.
In the new study, researchers reported on seven SMA patients who were administered Spinraza via the paramedian approach, using the aid of imaging guidance for needle placement. The patients ranged in age from 12 to 40; six had SMA type 2, and one had SMA type 1. Three of the patients had very severe scoliosis.
In total, 38 doses of the medication were given to these patients. All of the administrations were successful. In fact, in most (31 of 38), the injection was successful on the first attempt.
The administrations were generally short, with the median length of total stay clocked at 44 minutes. Further, there was no significant difference in administration time between individuals with or without severe scoliosis.
Most injections were administered without any side effects (adverse events), and no serious adverse events were reported. Reported adverse events included back pain, headache, nausea, and low blood oxygen levels.
“Intrathecal administration [of Spinraza] via the paramedian approach was successful in patients with SMA associated with scoliosis,” the researchers wrote.
By comparing their findings with previously published data, the team concluded that “intrathecal administration of nusinersen via the paramedian approach had the advantages of a high success rate and short procedure time with fewer adverse events in SMA patients with scoliosis.”
The researchers noted that this was a small, retrospective study, based only on the findings from one healthcare center.
“A multicenter analysis confirming our results is needed before our conclusions can be generalized to broader populations of patients,” they wrote.