Cyclophosphamide-free mobilisation increases safety while preserving the efficacy of autologous haematopoietic stem cell transplantation in refractory Crohn's disease patients.

BACKGROUND AND AIM: Autologous haematopoietic stem cell transplantation [AHSCT] is a therapeutic option for refractory Crohn's disease [CD]. However, high adverse event rates related to chemotherapy toxicity and immunosuppression limit its applicability. This study aims to evaluate AHSCT's safety and efficacy using a cyclophosphamide (Cy)-free mobilisation regimen. METHODS: A prospective observational study included 14 refractory CD patients undergoing AHSCT between June 2017 and October 2022. The protocol involved outpatient mobilisation with G-CSF 12-16 µg/kg/daily for 5 days, and optional Plerixafor 240 µg/d (1-2 doses) if the CD34+ cell count target was unmet. Standard conditioning with Cy and anti-thymocyte globulin was administered. Clinical, endoscopic, and radiological assessments were conducted at baseline and during follow-up. RESULTS: All patients achieved successful outpatient mobilisation (7 patients needed Plerixafor) and underwent transplantation. Median follow-up was 106 weeks (IQR 52-348). No mobilisation-related serious adverse events (SAEs) or CD worsening occurred. Clinical and endoscopic remission rates were 71% and 41.7% at 26 weeks, 64% and 25% at 52 weeks, and 71% and 16.7% at the last follow-up. The percentage of patients who restarted CD therapy for clinical relapse and/or endoscopic/radiological activity was 14% at 26 weeks, 57% at 52 weeks, and 86% at the last follow-up. Peripheral blood cell populations and antibody levels post-AHSCT were comparable to Cy-based mobilisation. CONCLUSIONS: Cy-free mobilisation is safe and feasible in refractory CD patients undergoing AHSCT. Although relapse occurs in a significant proportion of patients, clinical and endoscopic responses are achieved upon CD-specific therapy reintroduction.

Increased Serum Levels of N-terminal pro-B-type Natriuretic Peptide (NT-proBNP) in Mobilized Healthy Donors with G-CSF: A Cohort Study.

Limited data regarding elevation of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in mobilized donors with G-CSF is available. We extended these findings by examining serum NT-proBNP in a cohort study including 35 healthy donors and 69 patients who received G-CSF for CD34+ mobilization as well as 54 patients who did not receive G-CSF but who underwent collection of CD3+ cells for chimeric antigen receptor (CAR) T-cell manufacturing. No donor in the three cohorts experienced significant cardiac adverse events. NT-proBNP levels were measured before and after G-CSF administration and after finishing apheresis procedure. NT-proBNP increase was observed in mobilized healthy donors after G-CSF administration, but was not observed in mobilized or non-mobilized patients. Only in the cohort of healthy donors, pairwise comparisons using Wilcoxon signed ranks test showed a significant increase between the mean serum NT-proBNP level after G-CSF administration and the mean serum NT-proBNP level measured before G-CSF administration (231.09 ± 156.15 pg/mL vs. 58.88 ± 26.84 pg/mL; P < .01). No correlation was observed between NT-proBNP increase and G-CSF dose (rs = 0.09; n = 32; P = .6) and no other variables contributing to predict serum NT-proBNP increase were detected. In conclusion, we observed a statistically, although not clinically, significant increase of NT-proBNP in healthy donors who received G-CSF as CD34+ cell mobilization.

Hydrogen-bonded assemblies of iron(II) spin crossover complexes.

The paper reports on the synthesis, crystal structure, thermal and magnetic properties of spin crossover (SCO) salts containing the [Fe(bpp)2]2+ cation (bpp = 2,6-bis(pyrazol-3-yl)pyridine) and different rigid polycarboxylate anions, such as anthracene-9,10-dicarboxylate (ADC), benzene-1,3,5-tricarboxylate (BTC) and biphenyl-4,4'-dicarboxylate (BPDC). Compound [Fe(bpp)2](ADC)·9H2O (1) shows a porous hydrogen-bonded structure with water molecules sitting in the channels. It contains low-spin (LS) Fe2+ cations that undergo crossover to the high-spin (HS) state upon dehydration. Anhydrous 1 remains HS on cooling at low temperatures. A similar magnetic behaviour is obtained for the partially protonated BTC salt [Fe(bpp)2](HBTC)·5H2O (2), showing a spin change concomitant with dehydration to a HS phase that undergoes gradual and partial SCO on cooling, affecting 25% of the Fe2+ cations. Instead, the BPDC salt [Fe(bpp)2](BPDC)·5H2O (3) has a ground HS state in its fully hydrated form.

Effect of plasma exchange with albumin replacement on albumin functionality and organ dysfunction in acute-on-chronic liver failure.

Background & Aims: Effective treatments for acute-on-chronic liver failure (ACLF) are a major unmet need. This proof-of-concept pilot study was aimed at evaluating the effects of plasma exchange (PE) with albumin 5% (PE-A5%) on albumin functional capacity and organ dysfunction in patients with ACLF. Methods: Ten adult patients were enrolled in a single-center phase II, prospective, open-label, non-controlled study. Six PE-A5% sessions were performed in 10 days followed by a 1-month follow-up visit. Albumin functional capacity and circulatory function were assessed, as were renal, cerebral, and liver function, and systemic inflammation. The main safety variable was the percentage of PE sessions associated with at least one procedure-related adverse event (AE). Results: Patients with ACLF showed lower albumin binding capacity, lower antioxidant capacity, and lower levels of albumin with preserved structure compared to healthy donors (n = 19). From baseline to day 11, PE-A5% treatment increased albumin levels and improved albumin binding capacity to Sudlow site II (15.3±1.6 mg/ml to 18.9±1.7 mg/ml; p = 0.003), fatty acid-binding capacity (8.2±1.4 µM to 3.1±1.5 µM; p = 0.013) and antioxidant capacity (human mercaptalbumin 9.5±1.5 mg/ml to 14.6±1.6 mg/ml; p = 0.001). Native albumin levels were increased throughout day 1-11 PE-A5% sessions (6.5±1.0 mg/ml to 10.2±1.4 mg/ml; p = 0.035). PE-A5% improved systemic hemodynamics (mean arterial pressure, heart rate, cardiac index), renal function (creatinine level, blood urea nitrogen), cerebral function (hepatic encephalopathy grade), liver parameters (transaminases, bilirubin) and inflammatory parameters (C-reactive protein, leukocyte count). All patients had at least one of the 78 AEs reported, mostly mild (product/procedure-related: 36%). Sixteen serious AEs were reported in eight patients (procedure/product-related: none). Conclusions: PE-A5% was a safe procedure associated with positive effects on albumin functionality, and circulatory, renal, cerebral, and liver function in patients with ACLF. Impact and implications: Acute-on-chronic liver failure (ACLF) is a clinical condition characterized by severe systemic inflammation, organ failure, and high mortality. Plasma exchange removes patient's plasma containing pathogenic substances, replacing it with 5% albumin and fresh frozen plasma (PE-A5%). In this study, cirrhotic patients with ACLF were treated with PE-A5%, which was a safe procedure that increased binding and antioxidant capacity of patients' albumin, while improving circulatory, kidney, brain, and liver functions. These beneficial effects could impact survival in ACLF. ClinicalTrialsgov Identifier: NCT01201720. EudraCT number: 2010-021360-15.

EASIX and cardiac adverse events after allogeneic hematopoietic cell transplantation.

This study investigates the interaction between endothelial activation, indirectly measured using EASIX, and the probability of presenting cardiac adverse events (CAE) during the first year after allo-HCT. The 437 consecutive adults undergoing PB allo-HCT from 2012 and 2021 were included. EASIX was retrospectively calculated before and during the first 6 months after allo-HCT and transformed to log2-base to conduct the statistical analysis. The median age was 53, 46 (10.5%) patients had previous history of cardiac disease, MAC allo-HCTs were performed in 186 (42.6%) patients, and PTCY was administered in 242 (55.5%). The 1-year incidence of CAE was 12.6% (n = 55). The most prevalent cardiac events were heart failure and arrhythmias, 32.7% and 23.6% respectively, and the day +100 mortality rate of these patients was 40.5%. During the first 6 months after allo-HCT, EASIX trends were significantly higher in patients who developed CAE. Regression analyses confirmed that higher log2-EASIX values were predictors for higher risk for CAE during the first year after allo-HCT. This analysis identifies a significant association between higher endothelial activation, indirectly measured using EASIX, and higher risk for cardiac toxicity diagnosed during the first year after allo-HCT and extends the applicability of EASIX for identifying patients at risk for CAE.

ADAMTS13 recovery in acute thrombotic thrombocytopenic purpura after caplacizumab therapy.

ABSTRACT: Caplacizumab prevents the interaction between von Willebrand factor and platelets and is used to treat immune thrombotic thrombocytopenic purpura (iTTP). Its administration has been associated with a delay in ADAMTS13 activity restoration after plasma exchange (PEX) suspension. We analyzed the outcomes of 113 iTTP episodes, 75 of which were treated with caplacizumab, in 108 patients from the Spanish Registry of Thrombotic Thrombocytopenic Purpura. Caplacizumab shortened the time to platelet count normalization and reduced PEX requirement, exacerbations, and relapses. There was no difference in the time to achieve ADAMTS13 activity ≥20% after PEX end between caplacizumab-treated and nontreated episodes (median [interquartile range], 14.5 [7.7-27.2] vs 13.0 [8.0-29.0] days, P = .653). However, considering the 36 episodes in which caplacizumab was started ≤3 days after iTTP diagnosis, the time for ADAMTS13 restoration from PEX end was higher than in those episodes in which caplacizumab was started >3 days after iTTP diagnosis (20.0 [12.0-43.0] vs 11.0 [3.5-20.0] days, P = .003) or than in non-caplacizumab-treated episodes (P = .033). This finding could be related to a significantly shorter duration of PEX in early caplacizumab-treated episodes than in late caplacizumab-treated episodes (5.5 [4.0-9.0] vs 15.0 [11.0-21.5] days, P < .001) or non-caplacizumab-treated episodes (11.0 [6.0-26.0] days, P < .001). There were no differences in time to ADAMTS-13 restoration from PEX start (28.0 [17.2-47.5], 27.0 [19.0-37.5] and 29.5 [15.2-45.0] days in early caplacizumab-treated, late caplacizumab-treated and non-caplacizumab-treated episodes). Early administered caplacizumab does not prevent the requirement for immunosuppression but has beneficial effects by shortening PEX requirement without major safety concerns.

Therapeutic efficacy and safety of pathogen-reduced platelet components: Results of a meta-analysis of randomized controlled trials.

BACKGROUND AND OBJECTIVES: Clinical efficacy and safety of pathogen-reduced platelet concentrates (PR-PCs) concerning bleeding prevention are still debated despite conclusive real-world data from multiple countries where PR-PCs are transfused routinely. We performed a meta-analysis of randomized controlled trials (RCTs) comparing the clinical efficacy and safety of conventional platelet components (PCs) and PR-PCs prepared with the amotosalen/ultraviolet A light (INTERCEPT platelet concentrate [I-PC]) or riboflavin/ultraviolet light (Mirasol platelet concentrate [M-PC]) technologies, transfused in thrombocytopenic adult patients. MATERIALS AND METHODS: A literature search was conducted, and 10 RCTs met the criteria for inclusion in this meta-analysis. Summary odds ratios (ORs) of clinically significant bleeding (World Health Organization [WHO] bleeding grade ≥2), severe bleeding (WHO bleeding score ≥3) and all-cause mortality were calculated. RESULTS: The use of I-PC was not associated with an increase in the OR of clinically significant bleeding when compared to non-treated PCs (OR, 1.12; 95% CI: 0.89-1.41; p = 0.33), whereas transfusions with M-PC showed an increase in clinically significant bleeding (OR, 1.34; 95% CI: 1.03-1.75; p = 0.03). The OR of severe bleeding did not increase with either I-PC or M-PC (OR 0.88; 95% CI: 0.59-1.31; p = 0.52 for I-PC; OR 1.25; 95% CI: 0.66-2.37; p = 0.49 for M-PC). In the case of all-cause mortality, compared to non-treated PC, I-PC showed an OR of 0.61 (95% CI: 0.36-1.04; p = 0.07), and M-PC showed an OR of 3.04 (95% CI: 0.81-11.47; p = 0.1). CONCLUSION: No differences were observed concerning the clinical efficacy and safety of overall PR-PCs when compared to non-treated PCs. However, differences are evident when analysing platelets prepared with the two PR technologies independently.

T-TAS® 01 as a new tool for the evaluation of hemostasis in thrombocytopenic patients after platelet transfusion.

BACKGROUND: Current laboratory tests fail to evaluate the hemostatic function of platelets in patients with thrombocytopenia. We investigated the use of the Total Thrombus-Formation Analysis System (T-TAS® 01 [Fujimori Kogyo Co, Tokyo, Japan]) to evaluate hemostasis under conditions of experimental thrombocytopenia, and in patients before and after platelet transfusion. MATERIALS AND METHODS: Specific T-TAS 01 chips, for thrombocytopenic conditions, were used. The area under the curve (AUC) and occlusion time (OT, min) were measured in: (i) experimentally induced thrombocytopenia (183±15 to 6.3±1.2×103 platelets/µL) in blood samples from healthy donors (No.=13), and (ii) blood from oncohematological thrombocytopenic patients (No.=48), before and after platelet transfusion. The influences of hematocrit and number of transfusions were analyzed in these patients. RESULTS: Progressive reductions of AUC and prolongations of OT related significantly to decreasing platelet counts (p<0.05 for all) in experimental thrombocytopenia. In samples from thrombocytopenic patients, platelet counts, AUC and OT were, respectively, 10.8±0.6×103/µL, 175.2±59, and 27.2±1 min before transfusion; and 22±1.5×103/µL, 400.8±83 and 22.9±1.5 min after platelet transfusion (p<0.01 for all). A hematocrit below 25% or exposure to ten or more previous platelet transfusions had a negative impact on the T-TAS 01 performance in patients. In vitro correction of the hematocrit improved the hemostatic response in thrombocytopenic patients. DISCUSSION: T-TAS 01 measurements were sensitive to low platelet counts in the experimental setting. The technology was sensitive to evaluate the hemostatic capacity of platelet transfusions. Exposure to multiple medications, repeated platelet transfusions and lower hematocrits may interfere with the hemostatic performance in oncohematological patients with thrombocytopenia.

Endothelial Activation and Stress Index in adults undergoing allogeneic hematopoietic cell transplantation with post-transplant cyclophosphamide-based prophylaxis.

BACKGROUND AIMS: Post-transplant cyclophosphamide (PTCY)-based prophylaxis is becoming widespread for allogeneic hematopoietic cell transplantation (allo-HCT) performed independently of the selected donor source. In parallel, use of the Endothelial Activation and Stress Index (EASIX)-considered a surrogate parameter of endothelial activation-for predicting patient outcomes and clinical complications is gaining popularity in the allo-HCT setting. METHODS: We first investigated whether the dynamics of EASIX after allo-HCT differ between patients receiving PTCY and patients receiving other prophylaxis. We then investigated whether the predictive capacity of EASIX persists in PTCY-based allo-HCT. A total of 328 patients transplanted between 2014 and 2020 were included, and 201 (61.2%) received PTCY. RESULTS: EASIX trends differed significantly between the groups. Compared with patients receiving other prophylaxis, patients receiving PTCY had lower EASIX on day 0 and higher values between day 7 and day 100. In patients receiving PTCY, higher EASIX correlated significantly with higher non-relapse mortality (NRM) and lower overall survival (OS) when measured before and during the first 180 days after allo-HCT. In addition, higher EASIX scores measured at specific time points were predictors of veno-occlusive disease (VOD), transplant-associated thrombotic microangiopathy (TA-TMA) and grade 2-4 acute graft-versus-host disease (aGVHD) risk. CONCLUSIONS: This study demonstrates how EASIX trends vary during the first 180 days after allo-HCT in patients receiving PTCY and those not receiving PTCY and validates the utility of this index for predicting NRM, OS and risk of VOD, TA-TMA and grade 2-4 aGVHD in patients receiving PTCY.

The academic point-of-care anti-CD19 chimeric antigen receptor T-cell product varnimcabtagene autoleucel (ARI-0001 cells) shows efficacy and safety in the treatment of relapsed/refractory B-cell non-Hodgkin lymphoma.

Varnimcabtagene autoleucel (var-cel) is an academic anti-CD19 chimeric antigen receptor (CAR) product used for the treatment of non-Hodgkin lymphoma (NHL) in the CART19-BE-01 trial. Here we report updated outcomes of patients with NHL treated with var-cel. B-cell recovery was compared with patients with acute lymphoblastic leukaemia (ALL). Forty-five patients with NHL were treated. Cytokine release syndrome (any grade) occurred in 84% of patients (4% grade ≥3) and neurotoxicity in 7% (2% grade ≥3). The objective response rate was 73% at Day +100, and the 3-year duration of response was 56%. The 3-year progression-free and overall survival were 40% and 52% respectively. High lactate dehydrogenase was the only covariate with an impact on progression-free survival. The 3-year incidence of B-cell recovery was lower in patients with NHL compared to ALL (25% vs. 60%). In conclusion, in patients with NHL, the toxicity of var-cel was manageable, while B-cell recovery was significantly prolonged compared to ALL. This trial was registered as NCT03144583.

Post-Transplantation Cyclophosphamide and Tacrolimus for Graft-versus-Host Disease Prevention after Allogeneic Hematopoietic Cell Transplantation from HLA-Matched Donors Has More Advantages Than Limitations.

This study compared the efficacy of graft-versus-host disease (GVHD) prophylaxis with post-transplantation cyclophosphamide (PTCy) and tacrolimus (Tac) versus other regimens in 272 adults undergoing peripheral blood (PB) allogeneic hematopoietic cell transplantation (allo-HCT) from HLA-matched donors. Of these 272 patients, 95 (34.9%) received PTCy/Tac. The times to neutrophil and platelet engraftment were longer in the PTCy/Tac group (20 days versus 16 days for neutrophils and 19 days versus 12 days for platelets). The day +30 cumulative incidence (CuI) of bacterial bloodstream infection was higher in the PTCy/Tac group (43.2% versus 13.0%; P < .001). The CuIs of grade II-IV and grade III-IV acute GVHD (aGVHD) at day +180 were 14.7% and 4.2%, and the CuI of moderate/severe cGVHD at 2 years was 2.4% in the PTCy/Tac group and 41.8% (hazard ratio [HR], .29; P < .001), 15.8%, (HR, .24; P = .007), and 47.0% (HR, .05; P < .001), respectively, in the no-PTCy group. The duration of immunosuppression was shorter in patients receiving PTCy/Tac (6.2 months versus 9.0 months; P < .001). PTCy/Tac patients had higher OS (2 years: 74.3% versus 60.9%; HR, .54; P = .012), lower NRM (2 years: 8.6% versus 15.8%; HR, .54; P = .11), comparable CuI of relapse (2 years: 26.0% versus 24.4%; HR, 1.03; P = .89), and higher GRFS (2 years: 59.1% versus 16.7%; HR, .32; P < .001). Using PTCy/Tac in HLA-matched PB allo-HCT improved transplantation outcomes at out institution compared with previous prophylactic regimens, including a higher probability of survival despite more delayed engraftment and a higher rate of bacterial infection.

Applicability and validation of different prognostic scores in allogeneic hematopoietic cell transplant (HCT) in the post-transplant cyclophosphamide era.

We investigated the predictive capacity of six prognostic indices [Karnofsky Performance Status (KPS), Hematopoietic Cell Transplant-Specific Comorbidity Index (HCT-CI), Disease Risk Index (DRI), European Bone Marrow Transplantation (EBMT) and Revised Pre-Transplantation Assessment of Mortality (rPAM) Scores and Endothelial Activation and Stress Index (EASIX)] in 205 adults undergoing post-transplant cyclophosphamide (PTCy)-based allo-HCT. KPS, HCT-CI, DRI and EASIX grouped patients into higher and lower risk strata. KPS and EASIX maintained appropriate discrimination for OS prediction across the first 2 years after allo-HCT [receiver operating characteristic curve (area under the curve (AUC) > 55 %)]. The discriminative capacity of DRI and HCT-CI increased during the post-transplant period, with a peak of prediction at 2 years (AUC of 61.1 % and 61.8 %). The maximum rPAM discriminative capacity was at 1 year (1-year AUC of 58.2 %). The predictive capacity of the EBMT score was not demonstrated. This study validates the discrimination capacity for OS prediction of KPS, HCT-CI, DRI and EASIX in PTCy-based allo-HCT.

Diagnosis of Bone Marrow Necrosis following Severe Vaso-Occlusive Crisis in Patient with Compound Heterozygous Sickle Cell Disease.

Introduction: Bone marrow necrosis is a rare entity that can develop in context of a sickle cell disease vaso-occlusive crisis. Its physiopathology is related to an endothelial dysfunction taking place in bone marrow microvasculature. Case Presentation: A 30-year-old patient with history of compound heterozygous sickle cell disease was admitted following SARS-CoV-2 infection with fever and diarrhea. After initial favorable evolution, he developed a severe vaso-occlusive crisis with intense hemolysis and multi-organ ischemic complications. Patient then developed high fever and hypoxemia. With the suspicion of acute thoracic syndrome, a red blood cell exchange was performed. Respiratory symptoms ceased but patient persisted febrile with very high levels of acute phase reactants, persistent pancytopenia, and leucoerythroblastic reaction. An infectious cause was ruled out. Afterward, bone marrow aspiration and bone marrow biopsy showed a picture of bone marrow necrosis, which is an extremely rare complication of vaso-occlusive crisis but, paradoxically, more frequent in milder heterozygote cases of sickle cell disease. Ultimately, large deposits of complement membrane attack complex (particles C5b-9) were demonstrated after incubation of laboratory endothelial cells with activated plasma from the patient. Discussion: The clinical presentation and findings are consistent with a case of bone marrow necrosis. In this setting, the demonstration of complement as a potential cause of the endothelial dysfunction mimics the pattern of atypical hemolytic uremic syndrome and other microangiopathic anemias. This dysregulation may be a potential therapeutic target for new complement activation blockers.

Development of an in-house bone marrow collection kit: The Catalan bone marrow transplantation group experience.

BACKGROUND AND OBJECTIVES: Bone marrow (BM) harvesting is one of the essential sources of stem cells for haematopoietic stem cell transplantation. In 2019, commercial BM collection kits became unavailable in Europe. Consequently, we created an in-house BM collection kit as an alternative. MATERIALS AND METHODS: We compared two groups of BM collections. The first collections were taken using an in-house kit from June 2022 through February 2023 and the second with a commercial kit from February 2021 through May 2022. These all took place at seven collection centres (CC). We analysed the harvest quality (cell blood count, CD34+ cells, viability, potency and sterility), the incidents occurring with each kit and the time to neutrophil and platelet engraftment in recipients. RESULTS: A total of 23 donors underwent BM harvesting with the in-house kit and 23 with the commercial one. Both cohorts were comparable regarding donor characteristics, CC and time to procedure. No statistical differences were found in harvest quality between the in-house and commercial kits. A new transfusion set was required in three BM harvests (13%) with the in-house kit because of filter clogging. The median time to neutrophil and platelet engraftment was 21 days for both cohorts and 29 days (in-house) and 33 days (commercial), p = 0.284, respectively. CONCLUSION: The in-house BM collection kit offers a real approach to solve the diminished supply of commercial kits. A higher risk of filter clogging was observed compared with commercial kits due to the lack of 850 and 500 µm filters.

Real-world data of the use and experience of caplacizumab for the treatment of acquired thrombotic thrombocytopenic purpura: Case series.

PURPOSE: Caplacizumab was licensed for acquired thrombotic thrombocytopenic purpura (aTTP) based on prospective controlled trials. Real-world evidence is crucial in rare diseases. We aim to describe a patient population with aTTP, receiving caplacizumab in a real-world setting, reporting their outcomes, including safety and tolerability, and contrasting them with a historical cohort from our center. METHODS: We describe data collected retrospectively from 2012 to 2022 for 16 patients with aTTP (8 received caplacizumab and 8 the historical standard-of-care). Patients' characteristics and outcomes were compared between groups. RESULTS: Patients' demographic and baseline characteristics were similar in both groups. Caplacizumab led to a rapid normalization of the platelet count of 3.5 (IQR, 2-6) versus 16 (IQR, 9.5-23.5) days in the historical cohort: (p = .002). The median number of plasma exchanges and the length of days requiring them, between the caplacizumab group versus the historical cohort, was 6 (IQR, 6-10) versus 19.5 (IQR, 12.5-29.5) plasma exchanges (p = .006); and 9 (IQR, 8.5-13.5) versus 22 (15-31) days (p = .049), respectively. There were no refractory cases in the caplacizumab group in comparison with 37.5 % in the historical cohort. None of patients treated with caplacizumab experienced a recurrence after 1081 (IQR, 511-3125) days of follow-up. Safety was in line with data reported in clinical trials, with mild adverse events (mostly grade≤2). CONCLUSION: We provided real-world evidence in the treatment of aTTP, confirming the results obtained in clinical trials. Caplacizumab reduced the time to platelet count recovery and the number and length of plasma exchanges.