Eficácia e segurança da toxina botulínica no tratamento de indivíduos com paraparesia espástica tropical: um ensaio clínico randomizado duplo-cego e controle-placebo

Abstract

Introduction: Myelopathy associated to HTLV-1/tropical spastic paraparesis (HAM/TSP) is a progressive and disabling disease. Spasticity is one of the main symptoms, in which treatment focuses on antispastic drugs and rehabilitation programs. Botulinum toxin type A (BTA) is a consolidated intervention in the treatment of spasticity. However, there is a lack of studies on people with HAM/TSP. Objective: To evaluate the efficacy and safety of BTA in the treatment of people with HAM/TSP. Methods: Randomized, controlled, double-blind and placebo-controlled clinical trial, composed of individuals over 18 years old, diagnosed with HAM/TSP, who had not used BTA to treat spasticity. The primary outcomes were spasticity (modified Ashworth scale – MAS) and safety (adverse effects), and the secondary outcomes were pain (Michigan Body Map – MBM; and Visual Analogue Scale – VAS), functional motor independence (Motor Functional Independence Measure), spatial-temporal walk variables (10 meter walk test – 10mWT), functional mobility (Timed up and go test – TUG), performance in the sitting/standing (5-repetition sit/stand test – FTSST), functionality (World Health Organization Disability Assessment 2.0 – WHODAS 2.0) and quality of life (Short Form Health Survey 36 items – SF-36) were assessed before and 3 months after intervention. Participants were randomized into groups: BTA and placebo control (saline), stratified according to their ability to walk. The evaluator, neurologist and participants did not know which group they belonged to. Results: Two scientific articles were constructed. In total, 36 participants were analyzed, with a mean age of 59 (PD 14) years, and an average disease duration of 11 (PD 5) years. In the first study, in the BTA group, there was a difference in the physical aspects, pain, general health and mental health domains of the SF-36, and in the mobility domain of the WHODAS. In the placebo-control group, there was a difference in the mobility domain of the WHODAS, and in the pain domain of the SF-36. In the intergroup analysis, there was a difference in the general health status domain of the SF-36. There was no difference in the frequency of adverse effects. In the second study, there were no intra and intergroup differences in MAS, walk speed and cadence, step size, TUG and FTSST. Conclusion: BTA is safe for people with HAM/TSP. However, the first dose of BTA was not effective in treating people with HAM/TSP after 3 months of intervention. It is suggested that future studies identify profiles of people with HAM/TSP responding to BTA and determine more specific methods of therapeutic prescription of BTA for this population.