Yet evidence to date is favorable in children with early onset SMA. Dr. Bocchini wrote in the letter to Secretary Azar that “limited data suggest that treatment effect is greater when the treatment is initiated before symptoms develop and when the individual has more copies of SMN2.”
Dr. Kemper’s group concluded that screening can detect SMA in newborns and that treatment can modify the disease course. “Grey literature suggests those with total disease duration less than or equal to 12 weeks before nusinersen treatment were more likely to have better outcomes than those with longer periods of disease duration.
“Presymptomatic treatment alters the natural history” of the disorder, the group found, although outcome data past age 1 are not yet available. Based on findings from a New York pilot program, they predicted that nationwide newborn screening would avert 33 deaths and 48 cases of children who were dependent on a ventilator among an annual cohort of four million births.