Use of Leflunomide for Treatment of Cytomegalovirus Infection in Recipients of Allogeneic Stem Cell Transplant

ABSTRACT Cytomegalovirus (CMV) reactivations are common after allogeneic stem cell transplants, and pre-emptive therapy has been found to be effective. However, in India, treatment options are limited because of high cost and toxicity of ganciclovir and unavailability of cidofovir and foscarnet. Leflunomide is a cheap and easily available anti-rheumatoid arthritis drug that has been shown to have anti-CMV properties both in vitro and in vivo. It also has been used effectively for CMV reactivation after renal transplants. In this retrospective analysis, we analyzed 70 allogeneic stem cell transplants that were conducted between April 2015 and February 2017. There were 49 episodes of CMV reactivations in 43 patients in this period. Leflunomide was used in 24 episodes. It was effective in CMV clearance in 9 of the 24 episodes (38%). When the CMV copy number was 3 copies/mL, leflunomide was effective in 9 of 17 (53%) episodes, but when the copy number was >2 × 10 3 , leflunomide was ineffective in all of the 7 episodes. This difference was statistically significant ( P = .022 by Fisher exact test), suggesting that leflunomide may be more effective in clearance of CMV when copy numbers are low.