Caplacizumab prevents refractoriness and mortality in acquired thrombotic thrombocytopenic purpura: integrated analysis
Abstract The efficacy and safety of caplacizumab in individuals with acquired thrombotic thrombocytopenic purpura (aTTP) have been established in the phase 2 TITAN and phase 3 HERCULES trials. Integrated analysis of data from both trials was conducted to increase statistical power for assessing treatment differences in efficacy and safety outcomes. Caplacizumab was associated with a significant reduction in the number of deaths (0 vs 4; P < .05) and a significantly lower incidence of refractory TTP (0 vs 8; P < .05) vs placebo during the treatment period. Consistent with the individual trials, treatment with caplacizumab resulted in a faster time to platelet count response (ha…
Efficacy of Caplacizumab in Patients with aTTP in the HERCULES Study According to Baseline Disease Severity
Background: Acquired thrombotic thrombocytopenic purpura (aTTP) is a rare, life-threatening autoimmune thrombotic microangiopathy that involves abnormal processing of von-Willebrand factor (vWF) and results in multiple organ dysfunction. Although aTTP remains a very unpredictable disease, risk factors for death include older age, lactate dehydrogenase (LDH) levels >10x the upper limit of normal (ULN), and cerebral involvement (i.e., the French severity score) (Benhamou et al. Haematologica 2012;97:1181-1186). In addition, raised cardiac troponin-I (cTnI) levels of >2.5 µg/L have also been linked with a higher risk of mortality or refractoriness (Benhamou et al. J Thromb Haemost 2015;1…
Efficacy and safety of open-label caplacizumab in patients with exacerbations of acquired thrombotic thrombocytopenic purpura in the HERCULES study.
BACKGROUND Acquired thrombotic thrombocytopenic purpura (aTTP) is a rare, life-threatening autoimmune thrombotic microangiopathy. Caplacizumab, an anti-von Willebrand Factor Nanobody® , is effective for treating aTTP episodes and is well tolerated. OBJECTIVES AND METHODS In the phase 3 HERCULES trial (NCT02553317), patients with aTTP received double-blind caplacizumab or placebo during daily therapeutic plasma exchange (TPE) and for ≥30 days thereafter. Patients who experienced an exacerbation while on blinded study drug treatment switched to receive open-label caplacizumab plus re-initiation of daily TPE. Exacerbations were defined as recurrence of disease occurring within 30 days after ce…
Narratives of Patients with Fatal Outcomes During the Phase 2 TITAN and Phase 3 HERCULES Studies
Background: Acquired thrombotic thrombocytopenic purpura (aTTP) is a rare but life-threatening thrombotic microangiopathy, with an untreated mortality rate of >90%. Prompt treatment with therapeutic plasma exchange (TPE) and immunosuppression improves outcomes in patients with aTTP, but 10-20% of patients still die acutely from this disease. The aim of this analysis was to describe in more detail the characteristics and disease courses of the patients who died during the caplacizumab clinical development program. Methods: Patient narratives on all deaths occurring during the phase 2 TITAN and phase 3 HERCULES studies were extracted. Results: In the overall study periods, a total of 6 pat…
INTEGRATED EFFICACY RESULTS FROM THE PHASE 2 AND PHASE 3 STUDIES WITH CAPLACIZUMAB IN PATIENTS WITH ACQUIRED THROMBOTIC THROMBOCYTOPENIC PURPURA
Objective: An integrated analysis based on the Phase 2 TITAN (NCT01151423) and Phase 3 HERCULES (NCT02553317) studies with caplacizumab (CPLZ) in acquired thrombotic thrombocytopenic purpura (aTTP) was performed to assess treatment differences on efficacy and safety outcomes that may have been undetected in the individual trials. Methodology: In both trials, patients with an acute episode of aTTP were randomized to receive CPLZ or placebo (PBO) in addition to therapeutic plasma exchange (TPE) and immunosuppression. All randomized patients from both studies were included in the integrated efficacy analyses (CPLZ: n=108; PBO: n=112), and those who received at least 1 dose of the study drug we…
Redefining outcomes in immune TTP: an international working group consensus report
Abstract Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a potentially fatal thrombotic microangiopathy caused by autoantibody-mediated severe deficiency of ADAMTS13. Standardized definitions of response, exacerbation, remission, and relapse were initially proposed in 2003 and modified by the International Working Group for TTP in 2017. These definitions, which have been widely used in clinical practice and research, are based primarily on the platelet count and are benchmarked against the timing of discontinuation of therapeutic plasma exchange (TPE). They do not incorporate ADAMTS13 activity or the temporizing effects on the platelet count of caplacizumab, a novel anti–von W…
Efficacy of Caplacizumab in Patients with aTTP in the HERCULES Study According to Initial Immunosuppression Regimen
Background: Acquired thrombotic thrombocytopenic purpura (aTTP) is an acute, life-threatening thrombotic microangiopathy that requires urgent and specialized treatment. Prior to the introduction of caplacizumab, the treatment for aTTP was based on daily therapeutic plasma exchange (TPE; to replenish functional ADAMTS13 enzyme) plus immunosuppression (mainly corticosteroids and rituximab; to suppress anti-ADAMTS13 autoantibody production). TPE combined with immunosuppressive therapy improved outcomes in patients; however, episodes of aTTP are still associated with an acute mortality of up to 20% as these therapies do not have an immediate effect on the pathologic microvascular thrombosis. Th…
Severe plasma prekallikrein deficiency : clinical characteristics, novel KLKB1 mutations, and estimated prevalence
BACKGROUND Severe plasma prekallikrein (PK) deficiency is an autosomal-recessive defect characterized by isolated activated partial thromboplastin time prolongation. To date, no comprehensive methodologically firm analysis has investigated the diagnostic, clinical, and genetic characteristics of PK deficiency, and its prevalence remains unknown. PATIENTS/METHODS We described new families with PK deficiency, retrieved clinical and laboratory information of cases systematically searched in the (gray) literature, and collected blood of these cases for complementary analyses. The Genome Aggregation Database (gnomAD) and the population-based Gutenberg Health Study served to study the prevalence …
Safety of Caplacizumab in Patients Without Documented Severe ADAMTS13 Deficiency During the HERCULES Study
Background: Acquired thrombotic thrombocytopenic purpura (aTTP) is a rare, life-threatening autoimmune thrombotic microangiopathy caused by a deficiency in the activity of ADAMTS13 leading to the formation of ultra-large multimers of von Willebrand factor (vWF) and abnormal platelet adhesion in the microvasculature. aTTP requires prompt diagnosis and rapid initiation of treatment to limit the risk of negative or fatal outcomes. The clinical diagnosis of aTTP is based on thrombocytopenia and microangiopathic hemolytic anemia and is confirmed by ADAMTS13 <10%. However, the latter confirmation is not always rapidly available, and treatment is typically initiated based on the clinical diagno…
Detection and Differential Diagnosis of Prekallikrein Deficiency: Genetic Study of New Families and Systematic Review of the Literature
Abstract Introduction. Prekallikrein (PK) and high-molecular-weight kininogen (HK) deficiencies are ultra-rare, autosomal-recessive defects of the contact system caused by biallelic mutations in the KLKB1 and KNG1 genes, respectively. Since affected subjects do not manifest a bleeding phenotype, a correct diagnosis is essential to prevent the administration of prohemostatic agents or plasma and to avoid delay of surgery. We describe a new case of PK deficiency identified at UMC Mainz. In addition, we performed a systematic review of the literature in order to i) collect blood material for genetic studies of reported PK deficient cases lacking this information, and ii) perform a comprehensiv…