Perfil farmacoepidemiológico a partir de evidências de mundo real sobre o uso de nusinersena para Atrofia Muscular Espinhal 5q no SUS de Minas Gerais: desfechos clínicos e análise de sobrevida.

Abstract

Spinal Muscular Atrophy (SMA) 5q is a rare and severe autosomal recessive genetic disease characterized by progressive degeneration of motor neurons in the spinal cord and brainstem. This condition leads to loss of strength and motor function and is one of the main genetic causes of infant mortality. In Brazil, pharmacological treatment for SMA 5q is limited to three disease-modifying therapies provided by the Unified Health System (SUS): nusinersen, risdiplam, and onasemnogene abeparvovec, with use regulated by the Clinical Protocol and Therapeutic Guidelines (PCDT). Nusinersen, the first therapy approved by ANVISA in 2017, was incorporated into SUS in 2019 for type 1 SMA and, subsequently, in 2021 for type 2 SMA. Despite being a breakthrough in disease management, its high cost and the scarcity of real-world effectiveness evidence in the country reinforce the need for studies evaluating its clinical and social impacts. This study analyzed the utilization profile and clinical outcomes of nusinersen in patients with SMA 5q types 1 and 2 treated within SUS in Minas Gerais, from April 2019 to November 2024. It is an ambispective cohort using secondary data from administrative records of the Specialized Component of Pharmaceutical Services (CEAF) of the Minas Gerais State Health Department (SES-MG). Variables assessed included sociodemographic characteristics, nutritional status, respiratory function, motor outcomes (CHOP-INTEND, HINE-2, and HFMSE scales), overall survival, and factors associated with therapeutic failure. The results showed that children treated earlier presented better responses, with stabilization or slight motor improvement, as well as survival superior to historical estimates. Conversely, more advanced cases, with greater baseline functional impairment, had limited benefits and remained at risk of early death. Factors such as early treatment initiation and better baseline clinical condition were determinant for a more favorable prognosis. This study reinforces that, although nusinersen provides important clinical benefits, especially in the early stages of the disease, challenges remain regarding access, long-term outcome monitoring, and the financial sustainability of these high-cost technologies within SUS. The findings highlight the relevance of early diagnosis, newborn screening, and multidisciplinary care, while also providing evidence to improve public policies directed toward the care of people with SMA in Brazil.