Refractory Auto-Immune Thrombotic Thrombocytopenic Pupura Successfully Treated With Caplacizumab

Management of immune thrombotic thrombocytopenic purpura with caplacizumab: a Canadian, single-centre, real-world experience

When combined with therapeutic plasma exchange (TPE) and immunosuppression, upfront universal administration of caplacizumab was shown to be effective in the management of immune thrombotic thrombocytopenic purpura (iTTP). However, access to this drug remains challenging in many jurisdictions. We retrospectively review results of a single-institution experience with caplacizumab over a 3-year period. During the study period, we treated 48 patients with iTTP, of which 11 (23%) received caplacizumab. Eight of these 11 patients (73%) were female; the median age was 45 years (IQR 37.0-58.5). All received TPE within 24 h of admission (median 9 exchanges, IQR 7.0-12.5), and high-dose steroids. Caplacizumab was initiated for a median of 6 days after admission (IQR 2.5-8.0) and continued for a median of 26 days (IQR 14.0-33.0). Five patients (45%) had refractory disease at caplacizumab initiation. Ten patients (91%) survived, reaching clinical remission. Platelet normalization was reached with a median of 4 days following caplacizumab initiation (IQR 1.5-4.0). Complications included minor bleeding (n = 1) and local allergic reaction (n = 1). No patients experienced TTP exacerbation; relapse occurred in two patients (18%) over 1-5 years of follow-up. Caplacizumab appeared to be effective and safe, despite delayed initiation and in the setting of refractory disease.

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

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a rare and life-threatening thrombotic microangiopathy. Several studies have demonstrated the efficy 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 METHODS

We searched PubMed, Embase, and the Cochrane Library for studies until March 24, 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.

RESULTS

A 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 the 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.

CONCLUSIONS

Caplacizumab 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.