Spinraza Improves, Stabilizes SMA-related Motor Function: Study

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Spinraza (nusinersen) treatment was generally well tolerated and led to improved or stabilized motor function for nearly 300 children with spinal muscular atrophy (SMA) in Poland, a new study reports.

The study, “Safety, tolerability, and efficacy of a widely available nusinersen program for Polish children with Spinal Muscular Atrophy,” was published in European Journal of Paediatric Neurology.

Spinraza was the first disease-modifying therapy widely approved to treat SMA. Administered via injections into the spine, it works by boosting levels of the SMN protein whose deficit causes SMA.

Poland’s National Healthcare Fund approved Spinraza for reimbursement in treating all SMA types in 2019. Here, scientists in Poland, including several members of the Polish National SMA Treatment Program, reviewed outcomes for 298 children with SMA, ages 0 to 18, who started on Spinraza shortly after the reimbursement authorization in 2019.

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“Before 2019, [Spinraza] in Poland was only available to the 30 children with SMA type 1 in 3 hospitals. The combined efforts of medical professionals and patient advocacy organizations resulted in a treatment program that was financed from public funds and ensured access to [Spinraza] therapy to all SMA patients,” the scientists wrote.

Among the children, 43.5% had type 1 SMA, 23.3% type 2, and 31.8% type 3. The average age at treatment initiation was 6.9 years, and all of the patients were followed for at least a year.

At the end of the first year, 292 (98%) patients were still being treated with Spinraza. Of the six who weren’t, one was lost to follow-up, three switched to Evrysdi (risdiplam), and two had died. One death was due to heart failure and the other to respiratory failure; neither was related to treatment. No other serious safety-related events were reported.

Among patients with available data on the CHOP-INTEND, a standard measure of motor function, all their scores had either remained stable or improved after a year on Spinraza. The median change was an increase (improvement) of 8.9 points, which is considered clinically significant.

Scores on another motor function test, the HFMSE, generally followed the same trend with most patients showing marked improvement after a year of treatment.

Patients with better motor function scores when they started treatment tended to experience the most pronounced improvements with Spinraza, statistical analyses indicated. All but four of the patients were showing clear symptoms of SMA by the time they started treatment and among the four children who started it before showing symptoms, none had developed any symptoms after a year on Spinraza.

“Lower baseline scores were associated with a less significant response to treatment, but not with a lack of response, suggesting that there is no functional threshold below which [Spinraza] treatment should not be administered,” the researchers wrote.

The research team noted that, with the availability of Spinraza and other treatments, a newborn screening program has been initiated in Poland.

“This program is now fully underway and most patients in the treatment program in recent months have been diagnosed as newborns. Therefore, in the near future the results of [Spinraza] treatment in the whole cohort of SMA patients will likely be much better,” the researchers said.

Spinraza is sold by Biogen, which was not involved in this study, though some of the researchers disclosed having received honoraria from the company.