Antifibrotic effect after low-dose imatinib mesylate treatment in patients with nephrogenic systemic fibrosis: an open-label non-randomized, uncontrolled clinical trial

Background Nephrogenic systemic fibrosis is a disease affecting the connective tissue of the skin and internal organs in patients with renal failure. No effective treatments are available. Objectives To investigate if the tyrosine kinase inhibitor, imatinib mesylate was effective in patients with moderate to severe nephrogenic systemic fibrosis. Methods Among 25 patients with nephrogenic systemic fibrosis evaluated for the study from 1 October 2009 to 1 December 2010, four were included. They were treated with oral imatinib mesylate at a start dose of 400mg/day. Main outcome measure: Reduction of skin fibrosis and increase in joint mobility evaluated by the modified Rodnan skin score and a goniometer. Results In two patients, the imatinib mesylate dose was reduced to 200mg/day and in one patient to 100mg/day. Two patients were treated for 24weeks, one patient for 16weeks and one patient for 4weeks. Three patients experienced tethering of their skin which lessened with reduction in modified Rodnan skin score from 24 to 20, 24 to 17 and 21 to 14 but with very limited changes in joint mobility. The fourth patient discontinued the treatment due to a complicating infection. Conclusion Imatinib mesylate may be an effective drug in the treatment of skin fibrosis in moderate to severe NSF cases, even at reduced doses. We found a positive clinical effect on the skin, but no convincing improvement of the joint mobility. Only few patients could be recruited limiting the interpretation and conclusions of the results.