Efficacy and safety of caplacizumab in the treatment of thrombotic thrombocytopenic purpura: a systematic review and meta-analysis

BackgroundThrombotic thrombocytopenic purpura (TTP) is a rare and life-threatening thrombotic microangiopathy. Several studies have demonstrated the efficacy of caplacizumab in iTTP. However, the effect on different populations remains controversial. Therefore, we performed a systematic review and meta-analysis to assess the effectiveness and safety of caplacizumab for treating iTTP.Materials and MethodsWe searched PubMed, Embase, and the Cochrane Library for studies until 24 March 2023. Participants were hospitalized patients with iTTP. Interventions included caplacizumab versus placebo or standard of care (SOC). Outcomes assessed included all-cause mortality, exacerbation, relapse, refractory, time-to-platelet-count-recovery, length of TPE and hospital stay, bleeding, and thrombosis.ResultsA total of 1119 patients from eight studies were subjected to meta-analysis. The results of the meta-analysis showed that iTTP patients treated with caplacizumab achieved a reduction in mortality (RR 0.38, 95% CI: 0.19-0.75), exacerbation (RR 0.29, 95% CI: 0.14-0.61) and refractory (RR 0.50, 95% CI: 0.31-0.81). Besides, adding caplacizumab to SOC was associated with a shorten time-to-platelet-count-recovery (MD - 2.31, 95% CI: -3.86 to -0.77) and length of TPE (MD - 4.61, 95% CI: -6.20 to -3.02). In terms of safety, the bleeding rate was higher in the caplacizumab group (RR 1.57, 95% CI: 1.21-2.02), while there was no significant difference in hospital stay and thrombosis between the two groups.ConclusionsCaplacizumab is an effective treatment for patients with iTTP, especially in reducing all-cause mortality, exacerbations, refractoriness, and the time-to-platelet-count-recovery. Although the risk of bleeding may be increased, it is generally modest and manageable.