Long-term Efficacy of Treatments Monitored in Japanese Study
jREACT-SMA enrolls more than 100 adults; data expected in 2026
Researchers in Japan are conducting a study to better understand the natural history of spinal muscular atrophy (SMA) and how well disease-modifying therapies work in the real-world setting.
The Biogen Japan-sponsored study will draw on data from the Japan Registry for Adult Subjects of Spinal Muscular Atrophy (jREACT-SMA), which had enrolled 113 patients — exceeding the planned sample size of 100 — as of May 2022.
Participants in the registry will be followed for up to five years, with clinical data collected at least once a year. Results are expected in 2026, and the study is planned to conclude by March 2027.
The study’s protocol, “The Japan Registry for Adult Subjects of Spinal Muscular Atrophy (jREACT-SMA): Protocol for a Longitudinal Observational Study,” was published in the journal JMIR Research Protocols.
SMA is a rare genetic condition caused by mutations in the SMN1 gene that result in deficient levels of the survival motor neuron (SMN) protein. This protein is essential for the normal function and survival of motor neurons, the nerve cells that control movement, and its absence causes muscles to become gradually weaker over time.
While patients with the most severe forms of SMA normally do not survive past the first years of life, improvements in care over the past decade have resulted in a longer survival times, changing the natural history of the disease.
Also, three disease-modifying therapies received approval for SMA in Japan in the last six years. These SMA treatments have been shown in trials to slow or even stop some types of the disease from progressing, and are expected to improve disease prognosis. However, their benefit is best documented in babies and young children, particularly when started at an early age.
To know more about the natural history of the disease in modern days, as well as about the long-term effectiveness of approved disease-modifying therapies in the real-world setting, a team in Japan launched a registry study to follow adult patients with SMA over several years.
“This jREACT-SMA study will provide longitudinal prospective follow-up data in adult patients with SMA in Japan, including data on the natural history of the disease and data on the long-term effectiveness of disease-modifying therapies,” the team wrote.
The registry (UMIN000042015) began enrolling patients at 19 locations across Japan in late 2020. Eligible participants were those 18 years or older with a diagnosis of one of the five main types of SMA.
Patients also had to carry a genetically confirmed deletion or mutation of the SMN1 gene, and one or more copies of SMN2, a “back-up” gene that makes about 10% of all SMN protein in the body. Enrollment ended in December.
Assessing study participants
At entry to the registry, participants will be examined for measures of motor function and quality of life, as well as patient-reported outcomes. These measures also will be assessed at least once a year for up to five years until November 2025. Adverse events among patients receiving SMA treatments will be recorded.
Researchers will collect additional information from participants, such as past and ongoing medications, clinical and genetic data, blood test and lung function results, and nerve conduction test recordings.
“Using the results from the jREACT-SMA study, we expect to gain a better understanding of the pathophysiology of SMA and clinical data to support treatment decisions for overcoming potential therapeutic limitations in adult patients with SMA,” the team wrote.
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