Muscular Atrophy, Spinal, Type II

Spinal cord stimulation (SCS) has shown remarkable efficacy in restoring motor function in people with spinal cord injury by recruiting afferent input to enhance the responsiveness of spared neural circuits to residual cortical inputs. This pilot will test if SCS can show evidence to improve motor deficits in people with Type 2, 3, or 4 spinal muscular atrophy (SMA). The investigators will enroll up to six subjects with Type 2, 3, or 4 SMA aged 16 or older that show quantifiable motor deficits of the upper body. The investigators will then implant the subjects with percutaneous, linear spinal leads near the cervical spinal cord for a period of up to 29 days. Although these leads are not optimized for motor function but rather for their clinically approved indication of treating pain, the investigators believe they provide a safe technology enabling our team to perform scientific measurement necessary to evaluate potential for effects of SCS in motor paralysis with SMA. After the end of the study, the leads will be explanted.

There is no complete cure for SMA yet. However, the discovery of the genetic cause of SMA has led to the development of several treatment options that affect the genes involved in SMA - a gene replacement therapy called Zolgensma, and two drugs, called Nusinersen (Spinraza) and Risdiplam (Evyrsdi). In this context, the evaluation of efficacy and the long term follow-up of patients treated with these innovative treatments in clinical routine is one of the critical points. These evaluations are carried out in a medical context (clinical sites or research unit) using validated measurement tools and outcome measures. Carrying out these evaluations in a controlled environment can be considered from certain aspects as an advantage (reproducibility of measures, neutral environment, etc.), but also raises a certain number of questions regarding the impact on patients, the financial cost, or the relevance of the data obtained in an unnatural environment (stress, fatigue, patient motivation…). Also the regulatory authorities ask for longitudinal data for deciding to reimburse these expensive treatments. As such, the hospital cannot digest all these evaluations due to a lack of resources.

The study will evaluate safety and efficacy of intrathecal delivery of GC101 gene therapy drug as a treatment of spinal muscular atrophy Type 2 (SMA 2) patients.