'Devastating disease' that impacts young children could be treated with cancer drug: B.C. research

Researchers out of the University of British Columbia have found that an existing cancer drug could be used to treat muscular dystrophy.

Duchenne muscular dystrophy is a "severe genetic disorder that leads to progressive muscle weakness and degeneration due to disruptions to the protein dystrophin, which helps keep muscle cells intact," a UBC news release said.

Research conducted on mice suggested progression of the disorder could be slowed by a cancer drug known as a colony-stimulating factor 1 receptor inhibitor, by increasing the resiliency of muscle fibres. 

"This is a class of drug that is already being used in clinical trials to treat rare forms of cancer," says Dr. Farshad Babaeijandaghi, a postdoctoral fellow at UBC and first author of the study.

"To find that it could potentially serve a double purpose as a treatment for muscular dystrophy is incredibly exciting."

Babaeijandaghi says the drug shows a lot of promise and with further testing, it could improve the quality of life and even extend the life expectancy for muscular dystrophy patients.

Researchers say muscular dystrophy is the most common congenital disease in Canada and it impacts more males, with about one out of every 3,500 Canadian men and boys being diagnosed with the disease.

They add that symptoms typically appear in the early childhood years, and patients will face "increased loss of muscle function as they age."

Many patients are forced to rely on mobility aids as the disease progresses, and it eventually impacts their heart and lung function.

While researchers say improvements in cardiac and respiratory care have increased life expectancy in recent years, there is still no cure.

"Muscular dystrophy is a devastating disease that impacts children at a young age. While this is not a cure, it could significantly delay disease progression, helping people stay mobile and out of wheelchairs for longer," says the study's senior author Dr. Fabio Rossi.

"It could be used in conjunction with the other treatments and emerging gene therapy approaches aimed at the genetic defect."

Researchers say they were initially studying the role of resident macrophages — a type of white blood cell — in muscle regeneration.

They found the cancer drug not only depleted resident macrophages, but it had the unexpected effect of making muscle fibres more resistant to the type of contraction-induced tissue damage that is typical of muscular dystrophy.

"Many people will have heard that there are different types of muscle fibres, including fast-twitch and slow-twitch muscles," says Rossi. "By administering this drug, we observed that the muscle fibres actually started to transition to a slower-twitch type that is more resistant to damage caused by muscle contractions."

Researchers found the drug to be successful within just a few months of treatment, when testing it on mice with muscular dystrophy.

"The results were actually quite dramatic," says Babaeijandaghi. "The improvement in muscle resiliency was profound."

However, further studies will need to be done to determine if the cancer drug could be effective in treating muscular dystrophy in humans.

But several short-term clinical studies have shown that this class of drug is safe for people, researchers say, adding that they're hopeful a patient-ready treatment is on the horizon.

"Developing a new drug can be a long process," says Rossi. "But with the safety profile for this drug already being proven in human studies, it could mean we're on a fast track to a new treatment for muscular dystrophy."