0000000000186299
AUTHOR
Paul Coppo
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…
Immunogenic hotspots in the spacer domain of ADAMTS13 in immune‐mediated thrombotic thrombocytopenic purpura
International audience; Background Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is caused by anti-ADAMTS13 autoantibodies inducing a severe deficiency of ADAMTS13. Epitope mapping studies on samples obtained during acute iTTP episodes have shown that the iTTP immune response is polyclonal, with almost all patients having autoantibodies targeting the spacer domain of ADAMTS13.Objectives To identify the immunogenic hotspots in the spacer domain of ADAMTS13.Patients/methods A library of 11 full-length ADAMTS13 spacer hybrids was created in which amino acid regions of the spacer domain of ADAMTS13 were exchanged by the corresponding region of the spacer domain of ADAMTS1. Next, th…
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…
Long-Term Safety and Efficacy of Caplacizumab for Acquired Thrombotic Thrombocytopenic Purpura (aTTP): The Post-HERCULES Study
Abstract Background: The post-HERCULES trial (NCT02878603) evaluated long-term safety and efficacy of caplacizumab in patients with acquired thrombotic thrombocytopenic purpura (aTTP; also known as immune-mediated TTP), and efficacy of repeated use of caplacizumab for aTTP recurrence. Methods: Patients who completed the HERCULES trial were invited to participate in the post-HERCULES study and attend twice-yearly visits for 3 years. In case of aTTP recurrence, patients could receive open-label (OL) caplacizumab with therapeutic plasma exchange (TPE) and immunosuppression (IST). Safety was assessed during the overall study period (intention-to-observe [ITO] population) and during recurrences.…
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…
Open ADAMTS13, induced by antibodies, is a biomarker for subclinical immune-mediated thrombotic thrombocytopenic purpura
Recently, we showed that ADAMTS13 circulates in an open conformation during the acute phase of immune-mediated thrombotic thrombocytopenic purpura (iTTP). Although the cause of this conformational change remains elusive, ADAMTS13 is primarily closed in iTTP patients in remission with ADAMTS13 activity >50% and undetectable anti-ADAMTS13 autoantibodies, as well as after rituximab treatment, suggesting a role for anti-ADAMTS13 autoantibodies. Therefore, immunoglobulin G from 18 acute iTTP patients was purified and added to closed ADAMTS13 in healthy donor plasma. This resulted in open ADAMTS13 in 14 of 18 (78%) samples, proving that anti-ADAMTS13 autoantibodies can induce an open ADAMTS13 con…
Anti-ADAMTS13 autoantibody profiling in patients with immune-mediated thrombotic thrombocytopenic purpura.
Anti-A Disintegrin and Metalloproteinase with a ThromboSpondin type 1 motif, member 13 (ADAMTS13) autoantibodies cause a severe ADAMTS13 deficiency in immune-mediated thrombotic thrombocytopenic purpura (iTTP). ADAMTS13 consists of a metalloprotease (M), a disintegrin-like (D) domain, 8 thrombospondin type 1 repeats (T1-T8), a cysteine-rich (C), a spacer (S), and 2 CUB domains (CUB1-2). We recently developed a high-throughput epitope mapping assay based on small, nonoverlapping ADAMTS13 fragments (M, DT, CS, T2-T5, T6-T8, CUB1-2). With this assay, we performed a comprehensive epitope mapping using 131 acute-phase samples and for the first time a large group of remission samples (n = 50). Ne…