According to results from a meta-analysis published in Clinical and Applied Thrombosis/Hemostasis, treatment of acquired thrombotic thrombocytopenic purpura (TTP) with rituximab may result in lower rates of relapse and decreased mortality compared with the standard of care.
Researchers searched the EMBASE and MEDLINE databases for studies published prior to December 11, 2018. Cohort or randomized-controlled trials comparing clinical efficacy of rituximab with conventional therapy for TTP were included. There were 9 studies in total, 5 of which were prospective cohort studies and 4 of which were retrospective cohort studies.
Combined, the studies included 570 patients, with 280 patients in the rituximab arms and 290 patients in the conventional treatment arms. Although more than 30% of patients in the rituximab arms had relapsed or refractory TTP, just 22.8% of patients in the standard of care arms had relapsed or refractory disease.
Patients who received rituximab in the acute phase experienced significantly lower rates of relapse compared with patients who received conventional therapy (odds ratio [OR], 0.40; 95% CI, 0.19-0.85; P =.02), as did patients who received prophylactic rituximab (OR, 0.09; 95% CI, 0.04-0.24; P <.00001).
During follow-up, the groups that received standard of care treatment experienced a significantly higher mortality rate compared with the groups that received rituximab (OR, 0.41; 95% CI, 0.18-0.91; P =.03).
The authors noted that this meta-analysis had several limitations. For example, trials that relied on historical controls had significantly longer follow-up time in the control cohorts, resulting in artificially high relapse and mortality rates. Researchers could not assess a potential publication bias due to the limited number of studies included.
“Rituximab provided a high efficacy for preventing relapse in cases of newly diagnosed acquired TTP. Additionally, its effectiveness in the subgroup of patients with relapsed/refractory TTP was demonstrated through the provision of good outcomes,” the authors concluded.
1. Owattanapanich W, Wongprasert C, Rotchanapanya W, Owattanapanich N, Ruchutrakool T. Comparison of the long-term remission of rituximab and conventional treatment for acquired thrombotic thrombocytopenic purpura: a systematic review and meta-analysis [published online January 29, 2019]. Clin Appl Thromb Hemost. doi:10.1177/1076029618825309