US regulators have granted Novartis' experimental muscle wasting drug 'breakthrough' status, potentially giving it a fast-track to approval.

The US Food and Drug Administration has deemed BYM338 (bimagrumab) a potential breakthrough because, if it gets the green light, it could become the first treatment for patients with sporadic inclusion body myositis (sIBM), a rare but potentially life-threatening muscle-wasting condition. 

sIBM is the most common degenerative disease of muscle in adults older than 65 years, and is characterised by a slowly progressive, asymmetric, atrophy and weakness of muscles, often leaving patients wheelchair bound within 10 to15 years of onset. 

BYM338 is a novel, fully human monoclonal antibody developed by the Novartis Institutes for Biomedical Research, in collaboration with Morphosys, to help treat the condition by stimulating muscle growth.

The decision to award the drug breakthrough therapy came on the back of a Phase II proof-of-concept study - its data will be showcased at the American Neurological Association meeting in October - in which it "substantially benefited" patients with the condition compared to placebo, Novartis said.

"With no effective therapies currently available for sIBM, bimagrumab has the potential to be the first real option for patients with this condition," noted Timothy Wright, Global Head of Development at Novartis.

BYM338 is also in clinical development for chronic obstructive pulmonary disease, cancer cachexia, sarcopenia and in mechanically ventilated patients.