Repositioning Rheumatoid Arthritis Medication to Combat COVID-19-Induced Inflammation

The ongoing COVID-19 pandemic caused by the SARS-CoV-2 virus leads to severe inflammatory responses in multiple organs, often resulting in life-threatening conditions such as acute lung injury and respiratory distress syndrome. One of the main challenges in managing COVID-19 has been controlling the cytokine storm—a dangerous overreaction of the immune system—without impairing the body's ability to fight the virus.

Traditionally, glucocorticoids are employed to suppress these cytokine storms; however, they have the drawback of also weakening antiviral immune responses, delaying viral clearance, and sometimes worsening the disease outcome. To find safer alternatives, researchers from the Institute of Science Tokyo, in collaboration with the National Institute of Infectious Diseases, investigated the potential of an existing rheumatoid arthritis drug, iguratimod (IGU), as a treatment for severe COVID-19 symptoms.

Focusing on obese mice, which are more susceptible to cytokine storms due to visceral fat accumulation, the team administered SARS-CoV-2 to these animals and tested various treatments, including dexamethasone, a known anti-inflammatory medication, and IGU. Results demonstrated that mice treated with iguratimod exhibited significantly higher survival rates and milder lung inflammation compared to other groups. Notably, IGU also suppressed viral expansion in the lungs without hindering the immune response needed to combat the virus.

This contrasts with dexamethasone, which, while reducing inflammation, also dampened antiviral immune functions, leading to poorer outcomes. IGU’s ability to modulate inflammation without impairing immune defenses suggests it could be a promising candidate for repurposing as a COVID-19 therapeutic. Already approved for rheumatoid arthritis, IGU’s safety profile is well established, making it an attractive option for further clinical investigation.

The findings, published in the European Journal of Pharmacology, pave the way for potential clinical trials exploring iguratimod’s effectiveness in human patients, which could offer a safer, targeted approach to managing cytokine storms in COVID-19 cases. This research highlights the importance of drug repurposing in accelerating responses to emergent health crises.

Source: https://medicalxpress.com/news/2025-06-rheumatoid-arthritis-drug-excessive-inflammation.html