Relapses of thrombotic thrombocytopenic purpura after treatment with rituximab.

Rituximab has been added to therapeutic plasma exchange (TPE) in the last 10 years for refractory thrombotic thrombocytopenic purpura (TTP). We performed a retrospective single institution study to determine if patients with TTP treated with TPE and rituximab experienced relapses. We reviewed the electronic and apheresis records of patients treated between 2003 and 2008 and collected the following parameters: demographics, laboratory results, treatment characteristics, and follow-up. We identified 12 patients with ADAMTS13 <5% due to an inhibitor who received TPE and rituximab during the study period. The mean number of TPEs required to achieve remission was 24 ± 3, time to remission was 28 ± 3 days, and hospital length of stay was 36 ± 4 days. During a mean follow-up of 73.4 ± 6 months, four patients (33%) relapsed. On average, relapse occurred at 62 ± 8.5 months postachievement of remission. The one-year, three-year, and five-year relapse free-survival (RFS) rates were 92%, 75%, and 75%, respectively. On multivariate analysis, we failed to identify independent predictors of relapse. This retrospective analysis does not support the notion that rituximab prevents or decreases the rate of relapse in TTP. Prospective randomized studies are needed to confirm this observation.