According to a story from BioPharma Dive, the drug company BridgeBio has been working on the development of a new treatment for limb-girdle muscular dystrophy, a rare disease. At the moment, a company affiliate, ML Bio Solutions, is in the midst of enrolling patients in a phase 3 study that will evaluate the drug. More recently, the company has been in communication with the US Food and Drug Administration (FDA) and is anticipating seeking Accelerated Approval for the drug.
About Limb-Girdle Muscular Dystrophy
Limb-girdle muscular dystrophy (LGMD), also known as Erb’s muscular dystrophy, is a group of muscular dystrophies that are most characterized by progressive muscle atrophy that most prominently affects the muscles of the shoulders and hips. The precise genetic cause of the disorder varies depending on the subtype, but the end result is the same: the muscles are unable to form certain proteins that are necessary for normal muscular function. Symptoms may include oversized muscle fibers, weak shoulder muscles, respiratory muscle weakness, facial muscle weakness, lower back pain/discomfort, and heart palpitations. The rate of disease progression varies between individual cases. Onset is usually between the ages of 10 to 30 years. There are no disease modifying therapies for limb-girdle muscular dystrophy; management usually consists of physical, occupational, respiratory, and speech therapy. Though not always fatal, heart and respiratory muscle weakness can be life threatening. To learn more about limb-girdle muscular dystrophy, click here.
A Role for Accelerated Approval?
BridgeBio is hoping to seek Accelerated Approval after the FDA indicated that it was willing to accept the use of a surrogate endpoint. A surrogate endpoint is a critical requirement of Accelerated Approval. These endpoints suggest, but do not prove, clinical efficacy, and further trial study is required to demonstrate a drug’s efficacy after it has been cleared for use under Accelerated Approval.
The endpoint is derived from a muscular dystrophy biomarker. Data from this biomarker is expected to be available no later than early 2025. This biomarker involves levels of a certain shock-absorption protein that, when deficient, has been linked to the progressive muscle weakness that is found in limb-girdle muscular dystrophy.
This analysis will take place as part of the upcoming phase 3 trial at approximately the one-year mark when the protein, called αDG, is in a glyosylated state, which is believed to play a major role in how the disease develops. The complete trial, which will evaluate the drug’s effect on patient functionality as well, is expected to last three years in total.
The drug, designated BBP-418, showed promise in an earlier trial in patients with the type 2I form of the disease.
