Hemostatic Markers, Adamts-13 Profile and Anti-Sars-Cov-2 Antibody Levels in Patients with Immune Thrombotic Thrombocytopenic Purpura Receiving BNT162b2 Vaccination

Abstract Introduction: Patients (pts) with immune thrombotic thrombocytopenic purpura (iTTP) are at high risk of severe COVID-19, therefore protection from SARS-CoV-2 by vaccination is particularly relevant in this setting, although concerns may exist on possible adverse reactions or disease relapse after vaccination. In this study, in a group of iTTP pts who received in-hospital COVID-19 vaccination in a special program for 'fragile patients', we prospectively evaluated over time the antibody response, the clinical and laboratory disease parameters and hemostatic biomarker levels. Methods: Twelve iTTP pts in clinical remission and regularly followed-up in our Center were enrolled in April 2021, all of them received 2 doses of BNT162b2 vaccine (Pfizer-BioNTech) over 21 days, and were followed-up for clinical and laboratory testing for 60 days. Blood samples were collected at enrollment (day 0, D0) before the 1 st vaccine dose; on day 21 (D21) before the 2 nd dose; and on day 60 (D60) after the 1 st dose. Blood cell counts, anti-Spike receptor-binding-domain protein (anti-S/RBD) IgG, ADAMTS-13 activity, and anti-ADAMTS-13 IgG (chromogenic assay and ELISA), were measured at each time point. Additionally, an extensive study of hemostatic markers (i.e. FVIII, von Willebrand Factor (vWF) antigen and activity, fibrinogen, D-dimer, tPA, PAI, and F1+2) was performed. Follow up is currently continuing. Results: Median age of our cohort was 65 years with M/F ratio of 4/8. Median time since last acute iTTP episode was 40 months, median follow up of the cohort was 71 months (95% CI 30-126). All pts were in clinical remission, except one patient (P1) who had an iTTP relapse after contracting SARS-CoV-2 infection, in Dec 2020, and was on low-dose steroids on D0. One patient (P2) had an ADAMTS-13 relapse in Jan 2021, and received pre-emptive rituximab. No other pts were on immunosuppressive therapy. Concerning the status of ADAMTS-13 activity on D0, 6 pts showed normal levels (>50%), while 5 had a moderate (50-20%) and 1 a complete (<10%) ADAMTS-13 deficiency. This latter patient (P3) had normal ADAMTS-13 activity before the pandemic. All patients were negative for anti-ADAMTS-13 inhibitor. Further, on D0, the anti-S/RBD IgG testing was positive in 3/12 pts (median 704,1 AU/mL), due to symptomatic infection in 1 case (P1), and asymptomatic in 2 (P3 and 1 pt with ADAMTS-13 activity of 54%, P4). The study of hemostatic markers on D0 showed an increase in median levels of FVIII and vWF antigen and activity. These parameters were altered in 7/12, 11/12 and 8/12 pts, respectively. Fibrinogen and D-dimer were increased in 3/12 and 2/12, respectively. Notably, P1, P3 and P4 presented the highest levels of FVIII and vWF antigen, associated with high levels of vWF activity in P1 and P3 (mean 233%); moreover, P3 showed higher levels of D-dimer (708 ng/mL) and tPA (13 ng/ml). After the 2 doses of BNT162b2, no significant clinical side effects were reported, and no changes in platelet counts. ADAMTS-13 activity and inhibitors did not significantly change on D21 and D60. A complete ADAMTS-13 activity deficiency persisted in P3 on D21 and D60, associated with anti-ADAMTS-13 IgG titer >15 U/ml, despite clinical remission. Overall, a significant increase in anti-S/RBD IgG level was observed on D21 (p = 0.0005) and D60 (p = 0.0005). Remarkably, only P2 did not show an increase in anti-S/RBD IgG titer after both doses of BNT162b2. Median levels of FVIII and vWF antigen did not significantly change during follow up, while increased vWF activity was seen on D60 (p = 0.05). Fibrinogen levels were stable, and an increase in D-dimer (>1000 ng/mL both on D21 and D60) was seen in P3. There were no changes in the other hemostatic parameters, and no thromboses were observed. Conclusions: In our cohort of iTTP pts, COVID-19 was associated with 1 clinical and 1 ADAMTS-13 relapse. Our data show that SARS-CoV-2 vaccination was effective in inducing an antibody response in all but one patient who received rituximab within 3 months before vaccination, confirming recent findings. Overall, vaccination had no relevant impact on the hemostatic profile of our pts, and did not appear to be a driver of iTTP relapses. However, anti-SARS-CoV-2 antibodies monitoring in iTTP pts may be useful after vaccination, as currently it is unknown how long the antibody titer may persist. Although small, this study is in favor of efficacy and safety of mRNA vaccines in pts with iTTP. Disclosures Falanga: Bayer: Honoraria; Sanofi: Honoraria; Leo Pharma: Honoraria; Pfizer: Honoraria.

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Characteristics Behaviors of Coagulation and Fibrinolysis Markers in Acquired Thrombotic Thrombocytopenic Purpura

Journal of Intensive Care Medicine ◽

10.1177/0885066619899637 ◽

2020 ◽

pp. 088506661989963

Author(s):

Kazuya Sakai ◽

Hideo Wada ◽

Yuki Nakatsuka ◽

Masayuki Kubo ◽

Masaki Hayakawa ◽

...

Keyword(s):

Thrombotic Thrombocytopenic Purpura ◽

Operating Characteristic ◽

Characteristic Curve ◽

International Normalized Ratio ◽

Severe Thrombocytopenia ◽

Thrombocytopenic Purpura ◽

Fibrinogen Degradation Product ◽

Acute Medicine ◽

Cell Counts ◽

D Dimer

Introductions: Patients with acquired thrombotic thrombocytopenic purpura (TTP) show no severe abnormalities in coagulation or fibrinolysis. However, the exact extent of the abnormalities is unclear. Materials and Methods: This study analyzed 138 patients with acquired TTP and 46 patients with septic disseminated intravascular coagulation (DIC) who were included in a Japanese registry. Complete blood cell counts and 8 coagulation or fibrinolysis parameters were compared between the 2 groups. Results: Platelet counts in the acquired TTP group were significantly lower than those in the septic DIC group (P < .001). The international normalized ratio of prothrombin time and the activated partial thromboplastin time in the septic DIC group were significantly higher and longer, respectively, than those in the acquired TTP group (P < .01). The antithrombin (AT) values were significantly lower in the septic DIC group than in the acquired TTP group (P < .001), the latter of which were almost normal. Although both groups revealed elevations of fibrinogen degradation product (FDP) and D-dimer, these levels were significantly higher in the septic DIC group than in the acquired TTP group (P < .001). Of 138 patients with acquired TTP, 25 (18.1%) were diagnosed with septic DIC by the diagnostic criteria of the Japanese Ministry Health, Labour and Welfare, and 78 (56.5%) by those of the Japanese Association of Acute Medicine. Receiver operating characteristic curve analysis showed that acquired TTP could be diagnosed based on severe thrombocytopenia (<20 × 109/L), normal AT level (>87%), and mildly elevated FDP (<23 µg/mL). Conclusions: Our results indicate that 3 routine laboratory tests could differentiate between acquired TTP and septic DIC.

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Severe primary refractory thrombotic thrombocytopenic purpura (TTP) in the post plasma exchange (PEX) and rituximab era

BMJ Case Reports ◽

10.1136/bcr-2019-234091 ◽

2020 ◽

Vol 13 (6) ◽

pp. e234091

Author(s):

Sowmya Goranta ◽

Smit S Deliwala ◽

Tarek Haykal ◽

Ghassan Bachuwa

Keyword(s):

Effective Treatment ◽

Plasma Exchange ◽

Thrombotic Thrombocytopenic Purpura ◽

Clinical Remission ◽

Rare Case ◽

Platelet Response ◽

Treatment Intensification ◽

Thrombocytopenic Purpura ◽

Need For Treatment ◽

Emerging Therapies

Acute acquired thrombotic thrombocytopenic purpura (TTP) requires prompt recognition and initiation of plasma exchange (PEX) therapy and immunosuppression. When PEX fails, mortality nears 100%, making finding an effective treatment crucial. Primary refractory TTP occurs when initial therapies fail or if exacerbations occur during PEX therapy, both signifying the need for treatment intensification to achieve clinical remission. Rituximab helps treat most of the refractory TTP cases, except those that are severely refractory. A paucity of studies guiding severely refractory TTP makes management arbitrary and individualised, highlighting the value of isolated reports. We present an extremely rare case of primary refractory TTP with an insufficient platelet response to numerous types of treatments, including emerging therapies such as caplacizumab, on the background of repeated PEX and immunosuppressive therapies.

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ADAMTS13 Activity and Autoantibodies Subclasses as Recurrency Risk Predictors In Acquired Thrombotic Thrombocytopenic Purpura

Blood ◽

10.1182/blood.v116.21.2532.2532 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2532-2532

Author(s):

Giuseppe Bettoni ◽

Luca A Lotta ◽

Dario Consonni ◽

Dino FA Motti ◽

Roberta Palla ◽

...

Keyword(s):

Thrombotic Thrombocytopenic Purpura ◽

Recurrent Disease ◽

Random Effect ◽

Acute Disease ◽

Plasma Samples ◽

Adamts13 Activity ◽

Microangiopathic Hemolytic Anemia ◽

Thrombocytopenic Purpura ◽

Disease Remission

Abstract Abstract 2532 Background: Thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening disease characterized by acute episodes of thrombocytopenia and microangiopathic hemolytic anemia due to disseminated microvascular thrombosis. Up to 40% of patients with TTP who survive the first acute disease episode develop one or more recurrent episodes. The severe deficiency of the von Willebrand factor (VWF) cleaving protease ADAMTS13 in plasma and the presence of anti-ADAMTS13 autoantibodies during both acute presentation and disease remission are associated with increased risk for recurrence. However, additional markers are needed for an accurate prediction of the risk for recurrent disease. Anti-ADAMTS13 autoantibodies of different immunoglobulin (Ig) subclass, specificity and mechanisms of action have been described in patients with the autoimmune form of TTP. We sought to determine the relationships between anti-ADAMTS13 Ig subclasses and risk for recurrence in a large cohort of TTP patients. Patients and methods: TTP was defined using commonly accepted criteria (microangiopathic hemolytic anemia, thrombocytopenia and exclusion of alternative explanation for the disease symptoms). Anti-ADAMTS13 IgM, IgA, IgG and IgG1, IgG2, IgG3 and IgG4 subclasses were measured by ELISA in plasma samples obtained from a total of 115 patients with TTP referred to the Milan TTP registry. Plasma samples had been collected during acute disease presentation (n=60), disease remission (n=92) or both (n=37). ADAMTS13 activity and inhibitor were also measured. The levels of different Ig subclasses were compared between two groups of patients with or without recurrence during follow-up. Patients with a follow-up <24 months were excluded from analysis. Statistical analysis was performed using random effect linear regression models. Results: TTP patients had a median follow-up of 64 months (range 0–399). A total of 11 patients (9.5% of all patients) were followed-up for less than 24 months and excluded from further analysis. Of patients with a follow-up >24 months, 53 (50%) developed recurrences, whereas 51 did not. Recurrences occurred at a median of 24 months (45 days to 11 years) after the first episode and were more common in the first three years (n=35, 67%). Comparison of anti-ADAMTS13 Ig subclasses measured during acute disease presentation in TTP patients with recurrence and in patients without recurrence revealed lower levels of IgA (0.017 vs 0.243, p=0.05), IgG1 (0.076 vs 0.234, p=0.01) and IgG3 (0.126 vs 0.385, p=0.002) in recurrent patients, whereas IgG4 were higher in recurrent TTP (0.712 vs 0.289, p<0.0005). Notably, levels of IgA (random effect, p=0.018), IgG1 (random effect, p=0.005) and IgG3 (random effect, p=0.006) were also associated with lower platelet counts at presentation of acute TTP and IgG3 levels were associated with the number of plasma exchange procedures performed until remission/death. In TTP patients during remission lower levels of ADAMTS13 antigen (49.3 vs 69.5 p<0.0005) and activity (41.4 vs 75.5 p<0.0005) as well as high levels of anti-ADAMTS13 total IgG (21.93 vs 5.13 p=0.007) were confirmed to be predictors of recurrent disease. Other Ig subclasses, measured during remission were not associated with a history of recurrent TTP. The logistic analysis showed an odds of relapse of 4.2 (range 1.5–12 p=0.008) at remission in patients with reduced ADAMTS13 and of 4.4 (range 1.7–11.3; p=0.002) in patients with high levels of IgG, but not in the acute phase. Conclusions: Low values of ADAMTS13 and anti-ADAMTS13 autoantibodies showed and association with a fourfold increase of recurrency risk, while the same result is not confirmed for the acute phase. Anti-ADAMTS13 IgA, IgG1, 3 and 4 subclasses, measured at acute TTP presentation, showed association with recurrent disease in a retrospective cohort study of TTP patients. Ig subclass measurement might be useful to improve recurrence risk prediction in patients with TTP. Disclosures: No relevant conflicts of interest to declare.

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More rapid, robust and sustainable antibody responses to mRNA COVID-19 vaccine in convalescent COVID-19 individuals

10.1101/2021.08.04.21261561 ◽

2021 ◽

Author(s):

Sabrina E Racine-Brzostek ◽

Jim Yee ◽

Ashley Sukhu ◽

Yuqing Qiu ◽

Sophie Rand ◽

...

Keyword(s):

Longitudinal Study ◽

Antibody Response ◽

Real World ◽

Neutralizing Antibodies ◽

Vaccine Dose ◽

Antibody Responses ◽

Antibody Levels

Longitudinal studies are needed to evaluate the SARS-CoV-2 mRNA vaccine antibody response under real-world conditions. This longitudinal study investigated the quantity and quality of SARS-CoV-2 antibody response in 846 specimens from 350 subjects: comparing BNT162b2-vaccinated individuals (19 previously diagnosed with COVID-19 [RecoVax]; 49 never been diagnosed [NaiveVax]) to 122 hospitalized unvaccinated (HospNoVax) and 160 outpatient unvaccinated (OutPtNoVax) COVID-19 patients. NaiveVax experienced a delay in generating SARS-CoV-2 total antibody levels (TAb) and neutralizing antibodies (SNAb) after the 1st vaccine dose (D1), but a rapid increase in antibody levels was observed after the 2nd dose (D2). However, these never reached the robust levels observed in RecoVax. In fact, NaiveVax TAb and SNAb levels decreased 4-weeks post-D2 (p=0.003;p<0.001). For the most part, RecoVax TAb persisted throughout this study, after reaching maximal levels 2-weeks post-D2; but SNAb decreased significantly ~6-months post-D1 (p=0.002). Although NaiveVax avidity lagged behind that of RecoVax for most of the follow-up periods, NaiveVax did reach similar avidity by ~6-months post-D1. These data suggest that one vaccine dose elicits maximal antibody response in RecoVax and may be sufficient. Also, despite decreasing levels in TAb and SNAb overtime, long-term avidity maybe a measure worth evaluating and possibly correlating to vaccine efficacy.

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Serum D-dimer as a potential new biomarker for prognosis in patients with thrombotic thrombocytopenic purpura

Medicine ◽

10.1097/md.0000000000019563 ◽

2020 ◽

Vol 99 (13) ◽

pp. e19563

Author(s):

Hai-Xu Wang ◽

Bing Han ◽

Ying-Ying Zhao ◽

Lu Kou ◽

Lu-Lu Guo ◽

...

Keyword(s):

Thrombotic Thrombocytopenic Purpura ◽

Thrombocytopenic Purpura ◽

D Dimer

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Open ADAMTS13, induced by antibodies, is a biomarker for subclinical immune-mediated thrombotic thrombocytopenic purpura

Blood ◽

10.1182/blood.2019004221 ◽

2020 ◽

Cited By ~ 4

Author(s):

Elien Roose ◽

An-Sofie Schelpe ◽

Edwige Tellier ◽

György Sinkovits ◽

Bérangère S Joly ◽

...

Keyword(s):

Thrombotic Thrombocytopenic Purpura ◽

Adamts13 Activity ◽

Thrombocytopenic Purpura ◽

Follow Up Study ◽

Open Conformation ◽

Immune Mediated ◽

Long Term Follow Up ◽

Donor Plasma

Recently, we showed that during the acute phase of immune-mediated thrombotic thrombocytopenic purpura (iTTP), ADAMTS13 circulates in an open conformation. Although the cause of this conformational change in acute iTTP remains elusive, ADAMTS13 is mainly closed in iTTP patients (i) in remission with an ADAMTS13 activity >50% and undetectable anti-ADAMTS13 autoantibodies, and (ii) after rituximab treatment, suggesting a role for anti-ADAMTS13 autoantibodies. Therefore, IgGs from 18 acute iTTP patients were purified and added to closed ADAMTS13 in healthy donor plasma. This resulted in open ADAMTS13 in 14/18 (78%) samples, proving that indeed anti-ADAMTS13 autoantibodies can induce an open ADAMTS13 conformation. To further elucidate the conformation of ADAMTS13 in iTTP patients, we studied a novel iTTP patient cohort (n=197) that also included plasma samples of iTTP patients in remission where ADAMTS13 activity was <50%. The open ADAMTS13 conformation was not only found during acute iTTP but also in patients in remission with an ADAMTS13 activity <50% and in half of the patients with an ADAMTS13 activity >50%, although free anti-ADAMTS13 autoantibodies were not always detected. Thus open ADAMTS13 is not only a hallmark of acute iTTP, but also a novel biomarker to detect subclinical iTTP in patients in remission. Finally, a long term follow-up study in one iTTP patient showed that the open conformation precedes a severe drop in ADAMTS13 activity. In conclusion, we have shown that anti-ADAMTS13 autoantibodies from iTTP patients induce an open ADAMTS13 conformation. Most importantly, an open ADAMTS13 conformation is a biomarker for subclinical iTTP and could become an important tool in TTP management.

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Rituximab Does Not Prevent Relapse in Patients with Thrombotic Thrombocytopenic Purpura

Blood ◽

10.1182/blood.v120.21.3318.3318 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3318-3318

Author(s):

Goyal Jatinder ◽

Jose L. O. Lima ◽

Jill Adamski ◽

Marisa Marques

Keyword(s):

Thrombotic Thrombocytopenic Purpura ◽

Medical Records ◽

Conflicts Of Interest ◽

Univariate Analysis ◽

Laboratory Data ◽

Delayed Response ◽

Thrombocytopenic Purpura ◽

Group 2 ◽

Group 1

Abstract Abstract 3318 Objective: In the last decade, rituximab has been added to therapeutic plasma exchange (TPE) to treat patients with thrombotic thrombocytopenic purpura (TTP) who appear resistant to TPE. We sought to determine first if rituximab prevented TTP relapse. In addition, if relapse has occurred, we compared the rates of relapse of patients treated with TPE alone with those treated with a combination of TPE and rituximab. Methods: We retrospectively reviewed the medical records of all adult patients treated for TTP between 2003 and 2008 at our institution. TTP was defined as thrombocytopenia, hemolytic anemia and ADAMTS13 activity less than 10% due to an inhibitor. None of the patients had congenital TTP. Patient demographics, laboratory data, treatment characteristics and follow up details were collected from their electronic and apheresis' medical records. Kaplan-Meier curves were drawn for survival and Cox proportional hazards models were applied to look for independent predictors of relapse-free survival (RFS). Results: A total of 20 patients underwent TPE only (Group 1) as compared to 18 patients who also received rituximab during admission with TTP (Group 2). Table 1 shows that both groups were balanced at baseline for demographic and laboratory data. However, patients in group 2 had longer duration of hospital stay (p<0.0001), underwent more TPE procedures (p<0.0001) and took longer to achieve remission (p<0.0001). The mean follow up in group 1 was 77.5 (±22.4) months and in group 2 was 68.6 (±28.5) months. At follow-up, 5 patients from group 1 relapsed (25%) as compared with 6 patients from group 2 (35%) (p=0.50). The 1-year, 3-year and 5-year RFS rates were 95%, 85% and 74% for group 1, and 94%, 76% and 71%, respectively, for group 2 (p=0.53 using log rank test). On univariate analysis, only age at the time of treatment (p=0.05) and duration of follow-up after treatment (p=0.03) were predictors of relapse. However, on multivariate analysis, no independent predictors of relapse were identified. Conclusion: Rituximab does not prevent or reduce rates of relapse when used with TPE in patients with TTP. Since rituximab was added to patients later in their TPE course due to delayed response to treatment, it may yet have a role in decreasing the number of TPEs needed to achieve a response if it were started earlier during hospitalization for TTP. Disclosures: No relevant conflicts of interest to declare.

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Preemptive Rituximab Infusions Efficiently Prevent Relapses In Acquired Thrombotic Thrombocytopenic Purpura. Experience Of The French Thrombotic Microangiopathies Reference Center

Blood ◽

10.1182/blood.v122.21.448.448 ◽

2013 ◽

Vol 122 (21) ◽

pp. 448-448

Author(s):

Miguel HIE ◽

Julie Gay ◽

Lionel Galicier ◽

Francois Provot ◽

Sandrine Malot ◽

...

Keyword(s):

Thrombotic Thrombocytopenic Purpura ◽

Median Number ◽

Continuous Variables ◽

Adamts13 Activity ◽

Thrombocytopenic Purpura ◽

History Of ◽

Adamts13 Deficiency ◽

Group 2 ◽

Group 1

Context Acquired thrombotic thrombocytopenic purpura (TTP) results from a severe, antibody-mediated, deficiency in the von Willebrand factor-cleaving protease ADAMTS13. Rituximab is increasingly used in this indication in patients with a suboptimal response to plasma exchange. When severe acquired ADAMTS13 deficiency persists during remission, the estimated incidence rate is of 0.4/year. So far, it is still controversial whether preemptive rituximab efficiently prevents relapses in these patients. Patients and methods We defined two groups of patients with a history of acquired TTP who displayed a persistent severe ADAMTS13 deficiency during remission. Patients of group 1 were treated with preemptive infusions of rituximab. Patients of group 2 were managed in centers in which preemptive rituximab infusions were not the standard of care. The relapse incidence was evaluated and compared between both groups. Patients were treated according to National recommendations and enrolled from 12 French centers during a 12-year period. Patients were explored for ADAMTS13 activity and peripheral B-cell count every 3 months. Only patients with a > 12-month follow-up after rituximab administration are reported here. Median (25th - 75th percentile) was determined for all continuous variables. Wilcoxon’s test was used to compare continuous variables and the chi-square test or Fisher’s exact test to compare binary data. Relapse-free survival was compared between both groups using the Kaplan-Meier estimator with the corresponding 95% confidence interval. Results Forty-eight patients (20.6%) with a history of acquired TTP displayed a persistent severe ADAMTS13 deficiency on remission or experienced a subsequent severe ADAMTS13 deficiency (24 cases each) after a median follow-up of 17 months (12-29 months). Anti-ADAMTS13 antibodies concentration was 44 U/mL (24-59 U/mL). Thirty patients received preemptive infusions of rituximab (group 1), whereas 18 others had no therapeutical intervention (group 2). In group 1, 16 patients experienced a past history of TTP with a median number of 2 (1-3) episodes, corresponding to a relapse incidence of 0.22 (0-0.57)/year. Rituximab infusions were performed 14.5 months (6.5-27.4 months) after the last TTP episode. A median number of 4 (1-4) rituximab infusions were performed. The median follow-up between the first preemptive infusion of rituximab and the last ADAMTS13 evaluation is of 36 months (24-65 months). After preemptive rituximab administration, only 3 patients experienced a clinical relapse (0 [0] episode/year), corresponding to a significant reduction in the relapse incidence (P < .01). ADAMTS13 activity was 58.5% (30.5%-86.3%). Three months after the first rituximab infusion, ADAMTS13 activity was 46% (30-68); it further increased until the 12th month, and subsequently decreased. Accordingly, B-cell lymphocytes remained undetectable until the 6th month, and progressively increased at the 9th month to reach normal values at the 18th month. Nine patients (30%) required one (5 cases), two (2 cases), three (1 case) or ten (1 case) additional courses of rituximab for a further decrease or a persistent undetectable ADAMTS13 activity, which allowed to maintain a detectable ADAMTS13 activity in all but one patients. The time between two consecutive courses of rituximab was 26 months (5-59 months). At the end of follow-up, ADAMTS13 activity remained normal in 18 patients; 10 patients had a moderate ADAMTS13 deficiency, and 2 patients had a persistently undetectable ADAMTS13 activity. In four patients (13%), rituximab alone failed to increase durably ADAMTS13 activity, which required additional immunosuppressive drugs. In group 2, 14 patients relapsed after a 66-month follow-up (36-105 months), corresponding to a higher relapse incidence than in patients who received preemptive infusions of rituximab (0.23 [0.1-0.46] relapse/year, P<.01). Moreover, 2 patients died of TTP in group 2, whereas no fatal outcome was recorded in group 1. Relapse free survival over time was significantly longer in group 1 (Log-rank test: P = .049). Five patients experienced adverse effects including benign infections in 2 cases. Conclusion Rituximab efficiently prevents TTP relapses in most patients with a persistent acquired ADAMTS13 deficiency, with acceptable side effects. Disclosures: Off Label Use: Rituximab Rituximab may prevent relapses in acquired thrombotic thrombocytopenic purpura.

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A 14-Year Experience in the Management of Patients with Acquired Immune Thrombotic Thrombocytopenic Purpura in Northern Israel

Acta Haematologica ◽

10.1159/000371867 ◽

2015 ◽

Vol 134 (3) ◽

pp. 170-176 ◽

Cited By ~ 2

Author(s):

Nadav Rinott ◽

Tatiana Mashiach ◽

Netanel A. Horowitz ◽

Liliana Schliamser ◽

Galit Sarig ◽

...

Keyword(s):

Thrombotic Thrombocytopenic Purpura ◽

Median Number ◽

Retrospective Evaluation ◽

Thrombocytopenic Purpura ◽

Major Benefit ◽

Life Threatening ◽

Complicated Course ◽

Relapse Rates

Acquired idiopathic thrombotic thrombocytopenic purpura (I-TTP) is a life-threatening microangiopathic disorder usually treated with therapeutic plasma exchange (TPE). The current study assessed the role of rituximab in the treatment of complicated I-TTP. The sequence of TTP events was compared in a group of I-TTP patients treated with TPE and a cohort of refractory or relapsed patients who also received rituximab. This retrospective evaluation included 45 I-TTP patients, treated between January 2000 and October 2013, who underwent at least 3 TPE procedures and were followed up until December 2013 or death. Thirty-one patients with an uncomplicated course received TPE only. Fourteen patients had a complicated course due to either a primary refractory/exacerbated disease (n = 5) or relapse (n = 9) and received rituximab together with TPE. The median number of TPE procedures performed in the first TTP episode in the uncomplicated cohort and groups with primary refractory or relapsed TTP was 11, 27 and 45, respectively. The relapse rates per follow-up year in the uncomplicated I-TTP, primary refractory and relapsed I-TTP groups were 0.18, 0.2 and 0.6 episodes, respectively. After rituximab therapy this rate dropped to 0.2 per year in the relapsed subgroup. In conclusion, about a quarter of patients with I-TTP had a complicated course and experienced a major benefit from rituximab in terms of effectiveness and safety.

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Preemptive rituximab prevents long-term relapses in immune-mediated thrombotic thrombocytopenic purpura

Blood ◽

10.1182/blood-2018-04-840090 ◽

2018 ◽

Vol 132 (20) ◽

pp. 2143-2153 ◽

Cited By ~ 36

Author(s):

Matthieu Jestin ◽

Ygal Benhamou ◽

An-Sofie Schelpe ◽

Elien Roose ◽

François Provôt ◽

...

Keyword(s):

Thrombotic Thrombocytopenic Purpura ◽

Relapse Rate ◽

Thrombocytopenic Purpura ◽

Immune Mediated ◽

Key Points ◽

Long Term Follow Up ◽

Adamts13 Deficiency ◽

Risk Balance

Key Points TTP patients who display persistent and severe ADAMTS13 deficiency after remission have a relapse rate of 74% during long-term follow-up. Preemptive rituximab can decrease TTP relapses in 85% of patients with a favorable benefit-risk balance.

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