Rituximab Has Similar Efficacy in Treatment of Acute Refractory or Chronic Relapsing Idiopathic Thrombotic Thrombocytopenic Purpura (TTP) and Refractory Secondary TTP: A Systematic Review

Thrombotic thrombocytopenic purpura (TTP) is a potentially life-threatening disorder. Secondary TTP was known to be more resistant to plasma exchange and have higher mortality. Limited clinical data suggest that rituximab may be effective in the treatment of acute refractory or chronic relapsing nonfamilial idiopathic TTP (ITTP) as well as refractory secondary TTP (STTP). We performed a systematic review to evaluate the comparative efficacy of rituximab in ITTP and STTP.

An electronic literature search of Medline, CINAHL and the Cochrane library databases using the terms “rituximab” and “thrombotic” yielded 179 articles from March 2002 to June 2011. Studies were included if they met the following criteria: TTP in a first episode or subsequent relapse and TTP refractory to plasma exchange. Exclusion criteria were prophylactic administration of rituximab to patients in remission and familial TTP. Secondary TTP cases were author-defined. Case series without extractable individual data were excluded. Two-Tailed Fisher Exact Test was used to investigate the difference in complete remission rates between ITTP and STTP. Independent-Samples Mann-Whitney U Test was applied to detect the difference in platelet recovery days.

20 case series and 33 case reports including a small prospective study were eligible. Individual data of 139 patients from Europe, Asia, Australia, South and North America were analyzed. Overall, median age was 40 years (range: 1–72). Male constituted 30% and female 70%. Complete remission rate was 88% (90 out of 102) and 84% (31 out of 37) for ITTP and STTP respectively. There was no statistically significant difference in complete remission rates between the two groups (Two-Tailed Fisher Exact Test p value = 0.569). Median follow-up time was 12 months. Median platelet recovery (more than 150×10⁹/L) from the first dose of rituximab was 8 days (range: 2–74) and 19 days (range: 7–90) for ITTP and STTP respectively. The distribution of platelet recovery days was the same between ITTP and STTP (Independent-Samples Mann-Whitney U Test p value = 0.132).

Rituximab has the same efficacy in both STTP and ITTP in terms of response rate and platelet recovery days. It appears to be effective and well-tolerated. We recommend the use of rituximab as a salvage therapeutic modality in refractory acute or chronic relapsing nonfamilial idiopathic as well as secondary TTP.

No relevant conflicts of interest to declare.