Profile of patients diagnosed with spinal cord atrophy treated with an antisense oligonucleotide in a reference service in Minas Gerais

Background: Spinal muscular atrophy (SMA) is a disorder caused by homozygous loss of function of the SMN1 gene. This gene produces the survival motor neuron (SMN) protein, which is important in motor neuron homeostasis. The SMN2 gene has homology with SMN1, but only expresses 10% functional full-length SMN protein. The treatment available in the Brazilian public health system is Nusinersen, an antisense oligonucleotide that increases the proportion of functional SMN2 protein.

Objective: The aim of this study was to analyze the profile of patients with SMA treated with Nusinersen in a reference service in Minas Gerais.

Methods: We conducted a database analysis of patients with SMA followed up between 2020 and 2022.

Results: We analyzed the information from 33 patients who were candidates for receiving Nusinersen at our service. The criterias used were established by the Clinical Protocols and Therapeutic Guidelines (CPTG) from Brazilian Ministry of Health published in 2019. The refusals were made for cases that did not meet the criterias, such as permanent invasive ventilatory support, severe contractures or scoliosis and subtypes 0, 2, 3 or 4. Treatment was indicated for 20 patients. Among these, 15% were later excluded due to 1 death, 1 case of clinical worsening, 1 loss of follow-up and 4 changes of treatment to gene therapy. 14 patients received the first 4 doses in our service, whose ages ranged from 2,5 to 29 months with a mean of 10,3 months. 4 patients received it in another service through judicialization, before the medicine became available in the health system. The average time between the molecular diagnosis and the beginning of the treatment after the implementation of CPTG was 89,7 days. The Chop Intend motor scale implementation was impaired by COVID19 pandemic and patient's respiratory complications. However, it was used to follow up 6 patients, which had, 6 months after the first dose, a mean increment of 11.1 points, ranging from 6 to 22 points. Among these, 4 patients got a mean gain of 16 points at the 1-year evaluation and 1 patient achieved a maximum score at the 2 years follow up. Until now, the total number of Nusinersen's doses administered was 89 and there were no side effects reported.

Conclusions: The new treatments are modifying the clinical course of SMA. However, it is important to reduce the time between diagnosis and treatment to optimize results.

Die Autoren geben an, dass kein Interessenkonflikt besteht.

Publikationsverlauf

Artikel online veröffentlicht:
18. September 2023