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Antirheumatic agents

Reversing Muscle Wasting in Rheumatoid Arthritis Patients

Strategic Insights

— 2 min read

Newcastle University researchers have made a groundbreaking discovery in the treatment of rheumatoid arthritis, finding that an anti-rheumatic drug can reverse muscle wasting in patients. The study, published in The Lancet Rheumatology, involved 15 patients with rheumatoid arthritis who were given Tofacitinib, a Janus kinase (JAK) inhibitor. After six months, their leg muscles had increased in size, particularly in the thigh, with a 4% increase in muscle volume and an average increase of 242 cm3.

The study, known as the RAMUS study, aimed to investigate the effects of Tofacitinib on muscle wasting in patients with rheumatoid arthritis. Muscle wasting, or sarcopenia, is a progressive disease characterized by the loss of muscle mass, strength, and physical performance, increasing the risk of falls, fractures, physical disability, and mortality.

Key Takeaways:

  • The study found that Tofacitinib, a JAK inhibitor, can reverse muscle wasting in patients with rheumatoid arthritis, with a 4% increase in muscle volume and an average increase of 242 cm3 in the thigh.
  • The RAMUS study involved 15 patients with rheumatoid arthritis who were given Tofacitinib for six months, during which time their leg muscles increased in size.
  • The study also reported changes in the gene expression in muscle tissue with treatment, which were opposite to changes seen in ageing muscle.
  • Dr. Joshua Bennett, lead author of the paper, stated that while the study is small, it is the first to show that JAK inhibitor drugs may be able to reverse sarcopenia in rheumatoid arthritis.
  • Professor John Isaacs, Director of Research at Newcastle Hospitals and Deputy Director of the National Institute for Health and Care Research (NIHR) Newcastle Biomedical Research Centre (BRC), added that the findings support growing evidence that inflammation may contribute to muscle loss.

Statistics:

  • 15 patients were involved in the RAMUS study.
  • The study found a 4% increase in muscle volume after six months of Tofacitinib treatment.
  • The average increase in muscle volume was 242 cm3.
  • 13 patients experienced adverse events, the majority of which were mild.
  • The study was funded by Pfizer, with contributions from The BMA Foundation, the JGW Patterson Foundation, and the Newcastle Hospitals Charity.

Sources:

  • The Lancet Rheumatology - "Skeletal muscle effects of Janus kinase inhibition in rheumatoid arthritis (RAMUS): a single-arm, experimental medicine study" by Joshua L Bennett, John D Isaacs et al.
  • Newcastle University press release - "Muscle wasting reversed in patients with rheumatoid arthritis"
  • Original text: https://www.ncl.ac.uk/press/articles/latest/2025/10/anti-rheumaticdrug/?_gl=1*kaihai*_up*MQ..*_ga*NjI0NzY0Ny4xNzYwNzA4ODA1*_ga_VH2F6S16XP*czE3NjA3MDg4MDQkbzEkZzAkdDE3NjA3MDg4MDQkajYwJGwwJGgxNTY1OTMyMDc0

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