The incidence rate of spinal muscular atrophy (SMA) is rising, highlighting the urgent need for more effective treatment options. To combat this, researchers are gearing up for an innovative new clinical trial study that could significantly impact how we approach the treatment of SMA.

This new clinical trial sponsored by GeneCradle Inc. is expected to be completed by December 2025. It aims to evaluate the efficacy and safety of intrathecal delivery of gene therapy drug GC101 to treat patients with spinal muscular atrophy (SMA) type 1.

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SMA is a hereditary disorder characterized by wasting, or atrophy, and weakness of skeletal muscles that control movement. The underlying cause of this disease is the loss of specialized nerve cells, or motor neurons, responsible for muscle movement, the study team wrote. Typically, muscle weakness is more pronounced in the proximal muscles than in the distal muscles away from the center. The severity of muscle weakness tends to increase over time, they said.

There are several types of SMA, with type 1 being the most prevalent and severe form. This SMA type affects infants with noticeable muscle weakness at birth or within the first few months of life. Most children with SMA type 1 cannot control their head movements or sit up without support, the researchers noted.

Swallowing and breathing difficulty problems are common, leading to feeding difficulties and poor growth. Unfortunately, most children with SMA type 1 do not survive beyond early childhood due to respiratory failure, they added.

A total of 18 participants will be evaluated in the open-label dose-escalation clinical trial of GC101 for a short-term safety period of 52 weeks followed by a long-term follow-up period of 5 years upon the will of participants. Furthermore, GC101 will be administrated intrathecally. The primary analysis for safety and efficacy will be assessed when all patients reach 18 months of age on the motor milestone of sitting unassisted for at least 10 seconds.

The eligibility criteria for participants are set as infants (0 to 6 months of age), while the study inclusion criteria demand that the patients need to be 6 months of age or younger on the day of vector infusion with type 1 SMA characterized by the diagnosis of SMA based on gene mutation analysis with biallelic SMN1 mutations and 2 copies of SMN2, and the disease onset before 6 months of age.

The primary outcome of the study is the incidence of treatment-emergent adverse events, including safety and tolerability, while the secondary outcomes include a proportion of event-free survival patients, the ability to thrive, and the changes from baseline Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders score.

The study will allow researchers to identify the ideal dosage of GC101 for treating SMA type 1 and provide valuable insights into this treatment’s long-term safety and efficacy. If successful, this gene therapy could improve the quality of life for individuals with SMA type 1 and revolutionize treatment options for other genetic disorders.


Evaluation of safety and efficacy of gene therapy drug in the treatment of spinal muscular atrophy (SMA) type 1 patients – Updated April 21, 2023. Retrieved April 26, 2023