Investigational Cancer Drug May Treat Muscular Dystrophy

An experimental leukemia drug may increase muscle strength in patients with Duchenne muscular dystrophy.

An experimental drug that was previously assessed for use in cancer was found to be unsuccessful. However, the drug, SU9516, may prove effective in the treatment of Duchenne muscular dystrophy (DMD), according to a study published by Molecular Therapy.

DMD is caused by a mutated gene that leads to progressive muscle weakness and early mortality. Individuals can experience symptoms as young as age 3, and experience disease progression over time. Currently, there is no cure for the condition, but the FDA recently approved deflazacort (Emflaza) to improve muscle weakness.

Instead of repairing or replacing the faulty gene, SU9519 may be used to increase muscle repair to reinforce muscle structure in patients with DMD.

In the study, the authors screened more than 350,000 compounds and discovered SU9519 — developed to treat leukemia – may be effective treating DMD.

The investigators found that the drug improved muscle function in laboratory and animal models of DMD. These findings show that SU9516 may present a promising approach to treating conditions characterized by muscle weakness.

Patients with DMD lack the dystrophin protein, which keeps muscle cells intact. Without the protein, muscles lose strength and can become easily damaged.

“Our findings open the door to develop new drug treatments for DMD,” said lead researcher Juan Marugan, PhD.

In previous studies, the authors found that increasing the levels of α7β1 integrin, a structural protein, in muscle cells could treat DMD in mice. Increasing the expression of the protein was also observed to slow disease progression.

In the current study, the investigators screened for compounds that increased α7β1 integrin production in cell-based models. SU9516 was observed to increase integrin production and the formation of muscle cells and fibers from DMD muscle stem cells, according to the study.

The investigators found that SU9516 increased α7β1 integrin production in muscle cells from both human and mouse models of DMD. Further analysis revealed that the drug also improved muscle function and reduced disease progression, according to the study.

These findings suggest that SU9516 could be used as a monotherapy or in combination with other treatments for DMD.

The authors also report that the drug could be used for other muscle-related conditions, such as cachexia, which is a syndrome characterized by weight and muscle loss. Cachexia is often seen among patients who have late-stage cancer, an injury, or in elderly patients.

Next steps include working with medical chemists to customize the compound for DMD. They also plan to extract anti-cancer components of the drug that could be toxic, which would create a safer treatment to test in patients, according to the study.

“Integrin stabilizes muscle structure, and helps stimulate muscle repair and regeneration,” said lead researcher Dean Burkin, PhD. “If we can artificially increase its production with drugs, we think it can help protect muscle cells from damage.”