Abstract
Although steroids are routinely used as an adjunct to plasma exchange (PEX) therapy in the treatment of immune-mediated thrombotic thrombocytopenic purpura (iTTP), limited data regarding their efficacy or effect on ADAMTS13 biomarkers are available. We report the results of a prospective, randomized study that compared the effectiveness of prednisone or cyclosporine (CSA) as adjuncts to PEX in the treatment of iTTP. A total of 26 of the planned 72 subjects were enrolled and treated from November 2007 until February 2014 before the study was halted after a planned interim analysis. Fourteen patients were randomly assigned to the prednisone arm, and 12 to the CSA arm of the study. One patient died in each arm of the study, and 2 patients in the prednisone arm of the study failed to achieve a response and crossed over to the CSA arm, leaving 11 patients in each arm of the study evaluable for the primary end point of exacerbation. One of the 11 prednisone-treated subjects (9%) suffered an exacerbation, whereas 3 of the 11 (27%) patients in the CSA arm suffered an exacerbation. Although there was no significant difference in the exacerbation rate, suppression of the anti-ADAMTS13 antibodies and improvement in ADAMTS13 activity in the first month after stopping PEX were significantly better in the prednisone-treated subjects. Side effects were manageable and comparable in both arms of the study. These data demonstrate the superiority of prednisone over CSA as an adjunct to PEX in the suppression of the anti-ADAMTS13 antibodies and improvement in ADAMTS13 activity. This trial was registered at www.clinicaltrials.gov as #NCT00713193.