A drug-release gel that responds to disease activity in inflammatory arthritis is demonstrated in a mouse model in Nature Communications this week.

People with inflammatory arthritis experience periods when the disease has low activity and periods when it is highly active, known as flare-ups. Treatment methods that deliver a sustained dose of medicine cannot react and adapt to these changes, which likely results in non-optimal doses as the disease cycles through its activity.

Jeffrey Karp and colleagues sought to address this mismatch between disease activity and drug dose by developing a flare-responsive hydrogel. In cell and mouse models of inflammatory arthritis, the gel is degraded when exposed to arthritis-related enzymes. The gel can be loaded with different small molecules with the amount released correlated to the severity of the flare-up. When the gel is loaded with a corticosteroid used to treat arthritis, reduced arthritis activity is observed.

The authors suggest that the responsive hydrogel is a potentially promising approach for treating inflammatory arthritis. They caution however, that more work is necessary to improve the composition of the gel and tests in larger animals with human-sized joints are required before potential human clinical trials could be considered. The authors conclude that this could be a first step for designing treatments that respond to disease activity.