Infants with Spinal Muscular Atrophy (SMA) who do not yet show symptoms experience numerous benefits from Spinraza (nusinersen) treatment, according to data that Biogen will present at the Cure SMA 2017 Annual Conference in Orlando, Florida on June 29 to July 2.
Among the host of presentations that the company will contribute are findings that Spinraza could offset the need for permanent ventilation and prevent death in infants. It also could allow older children to reach a higher level of motor development compared to untreated SMA children. Moreover, infants already in need of ventilation benefited from the treatment, researchers showed.
“New Spinraza data continue to reinforce the positive results seen in clinical studies and in my own practice,” Thomas Crawford, MD, co-director, Muscular Dystrophy Association Clinic at Johns Hopkins Medicine, said in a press release.
The ENDEAR study included infants who had genetically confirmed type 1 SMA and were already showing symptoms of the disease. At the end of the study, 51 percent of the Spinraza-treated babies had improved on motor development milestones. In contrast, no placebo-treated infants improved.
The infants who got the medicine also survived longer without the need for permanent ventilation, and lived longer overall. Among infants who received Spinraza, 23 percent finally required ventilation, compared to 32 percent in the control group.
Spinraza-treated children in the CHERISH trial, aged 2-12, scored higher on the Hammersmith Functional Motor Scale–Expanded assessment — a tool to assess the severity of motor disability in SMA. More treated children — 17.1 percent compared to 10.5 percent — also achieved motor milestones as defined by the World Health Organization (WHO).
Researchers also shared an interim analysis of data from the ongoing Phase 2 NURTURE trial (NCT02386553). The study involves infants who have a genetic SMA diagnosis — with only two or three copies of the SMN2 gene that provides instructions for making the survival motor neuron protein — but were not yet showing symptoms.
At the time of data analysis, on Oct. 31 2016, none of the 18 infants treated with Spinraza had required breathing aid or died, and 89 percent had improved on the Hammersmith Infant Neurological Examination assessment.
Other assessments of motor development showed similar improvements, with 39 percent having a maximum score on the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND). Researchers also said that the majority grew normally.
Many of these infants had older siblings with SMA type 1 or 2, and researchers noted that some developed motor skills were never achieved by their siblings.
“The SPINRAZA clinical development program demonstrates the impact of early treatment. The additional NURTURE data extends this finding by showing substantial improvements in motor milestones, generally consistent with normal development among infants with SMA who have yet to manifest symptoms before they were treated with SPINRAZA,” Crawford said.
Wildon Farwell, MD, MPH, senior medical director of Clinical Development at Biogen, said that data presented at the Cure SMA 2017 Annual SMA Conference “further demonstrate the significant impact of Spinraza and the benefits of early treatment initiation.”
Additionally, analyses of safety data across the clinical trials showed that infants and children with SMA did not appear to have an increased risk for breathing difficulties or other issues related to the repeat sedation needed to inject the drug. Breathing difficulties were rather consistent with what can be seen in SMA children in general, researchers said.
The safety analyses also concluded that the majority showed that common adverse events in the trial were mainly issues experienced by SMA patients in general, or were linked to the spinal injection procedure. Most severe adverse events recorded during the trials were also not likely related to treatment.
Researchers took a closer look at the side effects linked to the spinal injections. Data showed that the rates and type of these side effects were similar in children with later-onset SMA with or without scoliosis.
“We are encouraged to see unprecedented motor function gains in infants on permanent ventilation and a continued favorable benefit-risk profile across a broad population, including no increase in risk of adverse events in children who have developed scoliosis,” Farwell said.
“As part of our mission to make a meaningful difference in the lives of those affected by SMA, we continue to collect and evaluate data to provide a deeper understanding of the impact of Spinraza across SMA populations and share those results with the SMA community,” he added.