Cancer drug which shows potential as treatment for muscular dystrophy

Researchers at the University of British Columbia's School of Biomedical Engineering have discovered that an existing cancer drug could have potential as a treatment for muscular dystrophy.

The researchers found that the drug — known as a colony-stimulating factor 1 receptor (CSF1R) inhibitor — helped slow the progress of Duchenne muscular dystrophy in mice by increasing the resiliency of muscle fibres.

DMD symptoms typically appear in early childhood, with patients facing increased loss of muscle function as they age. As the disease progresses, many patients are forced to rely on mobility aids, such as a wheelchair, with the disease eventually impacting heart and lung function. While improvements in cardiac and respiratory care have increased life expectancy in recent decades, there is currently no cure.

The findings caught the researchers by surprise while they were initially studying the role of resident macrophages — a type of white blood cell — in muscle regeneration.

During experimentation in mice, they found that CSF1R inhibitors, which deplete resident macrophages, had the unexpected effect of making muscle fibres more resistant to the type of contraction-induced tissue damage that is characteristic of muscular dystrophy. The drug had the effect of changing the type of muscle fibers in the animal's body from damage-sensitive type IIB fibers toward damage-resistant type IIA/IIX fibers.

After making the discovery the researchers tested the drug in mice with DMD. Within a few months of treatment, they began to see successful results. The mice that underwent treatment showed higher frequencies of damage-resistant muscle fibres and were able to perform physical tasks, like moderate running on a treadmill, with less muscle damage than their untreated counterparts.

The researchers say that further studies are needed to identify if CSF1R is effective at treating DMD in humans. Considering that several short-term clinical studies have already shown that this class of drug is safe for use in people, they're hopeful that it could mean a patient-ready treatment is on the horizon.

Reference:          

FARSHAD BABAEIJANDAGHI, RYAN CHENG, NASIM KAJABADI et. al, SCIENCE TRANSLATIONAL MEDICINE, 29 Jun 2022, Vol 14, Issue 651, DOI: 10.1126/scitranslmed.abg7504.