96% of Children Given Spinraza as Newborns Able to Walk in NURTURE Trial

Spinraza (nusinersen) continues to safely and effectively stop disease progression in children with spinal muscular atrophy (SMA) who were treated before 6 weeks old and symptom onset, according to updated data from the NURTURE trial.

With up to nearly five years of continuous treatment, all these children were alive and able to breathe unassisted. Most — 96% — were able to walk with assistance at an average age of nearly 4 years old.

“The impact of early and sustained Spinraza treatment on these infants and their families is remarkable. I’ve had the privilege to watch them grow into active young children, many of whom have experienced progress in motor function consistent with children their age who do not have SMA,” Kathryn Swoboda, MD, the trial’s principal investigator at the Massachusetts General Hospital (MGH) clinical site, said in a press release.

These findings were presented at the recent virtual Cure SMA Research & Clinical Care Meeting.

Biogen’s Spinraza, an approved therapy for all types of SMA, works by boosting the production of SMN — a protein essential for motor neuron health and lacking in SMA patients due to mutations in the SMN1 gene.

The global, open-label Phase 2 NURTURE study (NCT02386553) is evaluating the safety and effectiveness of Spinraza, given intrathecally (via the spinal canal) every four months, in 25 presymptomatic newborns genetically diagnosed with SMA.

As newborns, they started treatment before 6 weeks old, and were most likely to develop SMA type 1 or 2, as they had two (15 patients) or three (10 patients) copies of the SMN2 gene. The number of SMN2 copies is associated with the severity of the disease, with more copies resulting in milder forms of SMA.

NURTURE’s previous data on these then toddlers, an average of 26 months old, showed that all were alive and able to breathe on their own and sit without support. Many were able to walk with or without assistance.

This was in contrast with SMA’s natural disease progression, as untreated infants with type 1 and 2 are never able to walk. And those with type 1 — the most common and severe form — need permanent ventilation, or die, at a median age of 13.5 months.

Newly presented data comes from an interim analysis of continued Spinraza use for up to 4.8 years. As of February 2020, all children (median age, 3.8 years) were alive and free of the need for permanent ventilation.

Since the last cut-off data date (11 months earlier), Spinraza showed sustained benefits, with children continuing to maintain or make progressive gains in motor skills compared with SMA’s natural history.

All children previously able to walk with (92%) or without (88%) assistance maintained that ability. In addition, one child gained the ability to walk with assistance — pushing the mark to 96%.

This child also reached the maximum score on the CHOP-INTEND scale, used to assess motor skills in infants. This raised to 21 of 25 (84%) the total number of children achieving the maximum score. Without treatment, CHOP-INTEND scores drop with time in these patients.

Improvements in another motor function scale — the Hammersmith Functional Motor Scale Expanded — were also observed in children likely to develop type 1 disease.

Spinraza was well-tolerated, with no new safety concerns or treatment discontinuations due to adverse events.

Swoboda, who holds an endowed chair in neurogenetics and is director of the Neurogenetics Program at MGH, said that “the new results from NURTURE continue to bolster the substantial benefit of both prompt diagnosis and early and longer-term treatment with Spinraza.”

NURTURE has been extended for an additional three years, Biogen also announced. A longer-term study will allow evaluation of Spinraza’s safety and its effectiveness in children through 8 years old, and further understanding of early treatment in this patient population.