The Effects of Nusinersen Treatment on Respiratory Status of Children with Spinal Muscular Atrophy.

Background Respiratory involvement is the main factor predicting the prognosis of spinal muscular atrophy (SMA). Significant responses in motor functions have been demonstrated with nusinersen, but pulmonary outcomes are still varied. We aimed to explore the effects of nusinersen on the respiratory functions of patients with SMA. Methods Patients with SMA who were receiving regular nusinersen treatment in our tertiary care hospital were enrolled in this study. We evaluated the patients in terms of the necessity to ventilatory or nutritional support, presence of motor involvement and other comorbidities related with prognosis at three consecutive assessments. Results The study group consisted of 43 patients (18 type 1, 12 type 2, and 13 type 3) with SMA with a mean age of 27.8 months at diagnosis and 60.8 months at the beginning of nusinersen treatment. The respiratory function improvements were noted in six patients at third assessment. Early initiation of nusinersen was significantly correlated with reduced hospital admissions (P = 0.026). Nutritional support and weight gain were remarkable in the ventilatory-supported group. Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders scores were significantly higher in the non-tracheostomized group in patients with SMA type 1 (P < 0.005). Conclusions We posit that nusinersen may change the natural prognosis of SMA and improve care of children with SMA. Following up children with SMA for longer periods under nusinersen may be beneficial for understanding the effects of treatment. Results of our study need to be supported by future long-term studies to reach a consensus on nusinersen, considering the overall genetic and environmental status as well as the cost-effectiveness of the treatment.