New treatments for spinal muscular atrophy in Brazil: Nusinersen, on as emnogeneabeparvovec and risdiplam, A Review

Introduction: Spinal muscular atrophy (SMA), characterized by the destruction of alpha motor neurons in the spinal cord, is an autosomal recessive genetic disease that causes impairment in the neuromuscular development of patients and is caused, in the vast majority of cases, by a homozygous deletion in the survival gene motor neuron 1 (SMN1). Considering the reduced quality of life resulting from the disease, its treatment is extremely important. Threenew ─ and the only ─ drugs available (nusinersen, onasemnogeneabeparvovec, and risdiplam) are capable of improving motor performance and life expectancy of patients. Objective: To review studies involving the use of nusinersen, onasemnogeneabeparvovec, and risdiplam for the treatment of patients with SMA, discussing the effects and examining the benefits of these drugs. Methods: Qualitative integrative literature review of articles from the Pubmed, Google Scholar and Cambridge Libraries databases, using the descriptors “Spinal Muscular Atrophy”, “Atrofia Muscular Espinhal”, “Zolgensma”, “Onasemnogene Abeparvovec”, “Nusinersen”, “Spinal Muscular Atrophy Treatment”, “Atrofia Muscular Espinhal Tratamento”, “AVXS-101”, “Spinraza”, “Spinal Muscular Atrophy Gene Therapy”, “Atrofia Muscular Espinhal Terapia Gênica”, “Risdiplam” and “Evrysdi”. Results: The studies show that the use of these new treatments for SMA promoted improvements in motor function, decreased fatigue, and reduced length of hospitalization, in addition to contributing to an increase in patients' life expectancy. To measure these benefits, the analyzed articles used scores such as Hammersmith Motor Functional Scale Expanded (HFMSE), Revised Upper Limb Module (RULM), Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND), Children's Hospital of Philadelphia Adapted Test of Neuromuscular Disorders (CHOP ATEND), 6 Minutes Walk Test (6MWT) and Compound Motor Action Potential (CMAP). Conclusion: It is possible to conclude that nusinersen, onasemnogeneabeparvovec, and risdiplam are effective in the treatment of SMA, as they promote improvement in the motor and respiratory function of patients. In the search for the best therapy, it is necessary to take into account factors such astoxicity, route of administration, site of action, and cost of such drugs.