Kasthuri, Raj S.

Abstract Introduction: Antiphospholipid antibody syndrome (APS) is characterized by arterial or venous thrombosis, and/or adverse obstetric outcomes in the presence of persistent antiphospholipid antibodies (APab). Between 2–10% of all patients with APS are reported to present solely with anti beta-2 glycoprotein 1 antibodies (b2GP1 abs) (ref 1). In 2006 the Sapporo criteria were revised to include b2GP1 abs to the panel of diagnostic tests. While presence of a lupus anticoagulant (LA) has been found to correlate well with occurrence of thromboses, the prognostic and predictive roles of b2GP1 abs and anticardiolipin antibodies (ACLA) need better definition. Previous studies suggest both the severity of the initial event and the risk for recurrent events is greater among patients demonstrating presence of more than one APab on laboratory testing (ref 2 and 3), but this aspect needs further confirmation. Objectives: To identify the spectrum of clinical thrombotic and obstetric manifestations associated with the different APab profiles; To determine the prevalence and clinical significance of the b2GP1 ab positive and ACLA/LA negative phenotype; and To evaluate the significance of IgM b2GP1 ab and IgM ACLA. Methods: Medical records of patients tested for all three antiphospholipid antibodies at the University of Minnesota Medical Center from Dec 2000 to Dec 2005 were reviewed. Patients that met the modified criteria for APS were included. IgG and IgM ACLA were measured using the Diamedix kit (VAX diagnostics) and IgG and IgM b2GP1 abs using the Inovalite kit (NOVA diagnostics). LA was determined using standard protocol. Results: Over the 5 year period, all three laboratory assays were obtained in 560 individuals, but only 76 (13.5%) patients who met both the clinical and laboratory criteria for APS were included in this study. Seven of the 76 patients (9.2%) had isolated, persistently positive b2GP1 abs. LA alone was present in 21 patients (27.6%). Twenty nine patients (38%) had all three APabs, and had a higher incidence of thrombosis at multiple sites at the time of diagnosis as well as increased rate of recurrent events, in comparison to those with two or less than two APab. Isolated ACLA was present in only 2 patients (2.6%). Interestingly, both IgM (47%) and IgG (50%) b2GP1 abs were associated with thrombosis, whereas only IgG ACLA was found to be associated with thrombosis. Conclusion: The presence of b2GP1 abs as the sole laboratory anomaly is uncommon, but is noted in patients with APS, thus warranting it’s testing at the time of clinical suspicion. Amongst the different antibody types LA seems to be the strongest predictor for thrombotic events and ACLA seems to have a weaker link, consistent with the results of previous studies (ref 4). The presence of all three AP antibodies does increase the risk for recurrent and multiple thromboses.

Introduction The United States Thrombotic Microangiopathy (USTMA) Consortium consists of high-volume US referral centers that are committed to collaborative research in TMAs. The USTMA Immune Thrombotic Thrombocytopenic Purpura (iTTP) registry has compiled retrospective data on demographics, treatments and outcomes in patients with iTTP to create the world's largest database of patients with this rare disease. While there is consensus on the use of therapeutic plasma exchange (TPE) for treatment of iTTP, there are no large randomized trials on which to base use of rituximab. The drug is frequently used for refractory or relapsed iTTP, but is currently being used more frequently for de novo (first episode) iTTP. We queried the USTMA iTTP registry to determine whether relapse free survival (RFS) is superior when rituximab is added to TPE and corticosteroids for treatment of iTTP. We hypothesized that the addition of rituximab would improve RFS at 5 years in both de novo and relapsing iTTP. Methods Following IRB approval at each institution, investigators independently reviewed individual patient records to confirm diagnostic criteria and entered demographic, treatment and outcomes data into the REDCap database housed at the University of North Carolina. The diagnosis of iTTP was defined as ADAMTS13 < 10% or ADAMTS13 < 20% with an inhibitor or antibody detected at any point or a clinical diagnosis of iTTP based on presenting characteristics, response to treatment and/or relapsing phenotype before ADAMTS13 testing became available (N=173). Relapse was defined as a recurrence of iTTP after at least 30 days of remission (recurrence within 30 days was considered an exacerbation, or continuation of the prior episode). To explore the effect of rituximab added to TPE and corticosteroids, we first assessed the treatment effect in de novo iTTP patients and then separately in relapse. We constructed Kaplan-Meier curves to compare RFS for patients treated with rituximab plus corticosteroids versus corticosteroids alone in both groups, and compared RFS at specific time points using the Klein method. To better understand whether other patient variables had an effect on RFS in both de novo episodes and relapses, ordinary (time-to-event) and mixed-effects (recurrent time-to-event) Cox proportional hazards models were used to examine the relationships of treatment, race/ethnicity, sex, age, treatment year, and presenting signs/symptoms with the outcome. Analyses were conducted using R version 3.5.2 (R Foundation for Statistical Computing, Vienna, Austria). Results As of July, 2019, the USTMA database contains 775 unique study patients with a confirmed diagnosis of iTTP with 1397 unique iTTP episodes. The treatment of patients' de novo iTTP episode was available for analysis in 375 patients, 188 of whom were treated with corticosteroids alone, 131 with corticosteroids plus rituximab, and 56 with other therapies. RFS was significantly higher in patients treated with corticosteroids and rituximab compared to those treated with corticosteroids alone at 1 year (0.93 vs. 0.78, p=0.0002) and 3 years (0.82 vs. 0.66, p=0.004) but not 5 years (0.60 vs. 0.56, p=0.39). In addition, the risk of relapse decreased with later treatment year for de novo iTTP (hazard ratio (HR) 0.95, 95% CI 0.92-0.99, p=0.03), consistent with rituximab use increasing over time, and was increased in African Americans compared with Caucasians (HR 1.83, 1.10-3.06, p=0.02). We then explored the treatment effect in all iTTP relapses (743 relapses in 426 patients). Here, a significant (p=0.0007) interaction between treatment and race was found. Among African Americans, we found no difference in RFS when rituximab was added (HR 1.15, 0.81-1.62, p=0.43). However, among Caucasians, RFS was significantly improved when rituximab was added (HR 0.15, 0.06-0.35, p<0.0001). Conclusions For de novo iTTP, adding rituximab to corticosteroids for immunosuppression likely delays but does not prevent relapse. Unlike in de novo disease, in patients with relapsed iTTP, we found a novel and significant interaction between race and treatment: while Caucasians had significantly improved RFS with the addition of rituximab, there was no effect on RFS in African Americans. Further investigation is warranted to determine the mechanisms of this difference in the response to rituximab in relapsed iTTP to improve outcomes in African Americans. Figure Disclosures Marshall: Sanofi: Membership on an entity's Board of Directors or advisory committees. Farland:Sanofi: Membership on an entity's Board of Directors or advisory committees. Metjian:Sanofi: Membership on an entity's Board of Directors or advisory committees. Raval:Bayer, Inc: Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees. Liles:Imara: Other: PI on Clinical trial- Sickle cell ; Shire: Other: PI on clinical trial Sickle cell ; Novartis: Other: PI on clinical trial Sickle cell . Baumann Kreuziger:CSL Behring: Consultancy; Vaccine Injury Compensation Program: Consultancy. McCrae:Rigel Pharmaceutical: Membership on an entity's Board of Directors or advisory committees; Sanofi Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Dova Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Pfizer Pharmaceutical: Membership on an entity's Board of Directors or advisory committees. Chaturvedi:Shire/Takeda: Research Funding; Sanofi: Consultancy; Alexion: Consultancy. Zheng:Clotsolution: Other: Co-Founder; Shire/Takeda: Research Funding; Ablynx/Sanofi: Consultancy, Speakers Bureau; Alexion: Speakers Bureau. Cataland:Ablynx/Sanofi: Consultancy, Research Funding; Alexion: Consultancy, Research Funding. Off Label Disclosure: rituximab for immunosuppression in TTP.

Introduction : Hereditary hemorrhagic telangiectasia (HHT, Osler-Weber-Rendu disease) is a rare hereditary multisystem vascular disease of disordered angiogenesis. Pathologic elevations in vascular endothelial growth factor (VEGF) result in fragile, abnormal vessels in nasal and gastrointestinal (GI) mucosa causing recurrent epistaxis, chronic GI bleeding, and anemia that is often transfusion-dependent. Bevacizumab is a monoclonal IgG1 antibody that neutralizes circulating VEGF and is a potential targeted anti-angiogenic treatment in HHT, which has no FDA-approved therapy. Data for use of intravenous (IV) bevacizumab in HHT is currently limited to case reports and small single-center retrospective case series. The International HHT Intravenous Bevacizumab Investigative Team study of Bleeding (InHIBIT-Bleed) is an international collaboration of HHT Centers seeking to more definitively describe the safety and effectiveness of systemic bevacizumab to treat chronic bleeding and anemia in HHT. Methods : The following data was retrospectively collected at each participating center for all HHT patients treated for at least 3 months with off-label systemic bevacizumab for chronic bleeding: demographics, baseline HHT characteristics, epistaxis severity score (ESS, a validated 10-point scale to evaluate epistaxis in HHT), bevacizumab dosing, treatment-emergent adverse events (TEAEs), hemoglobin (Hgb), red blood cell (RBC) transfusions, and IV iron infusions. Hgb and ESS at baseline were compared with post-bevacizumab values at 3, 6, 9, and 12 months with the paired t-test. RBC transfusion and iron infusion requirements before and after bevacizumab treatment were compared with the Wilcoxon signed rank test. Results : 140 HHT patients were treated with IV bevacizumab for chronic bleeding for a median of 23 (range, 3-96) months with a median of 12 (range, 2-74) total infusions. Bevacizumab was dosed at 5 mg/kg every 2 weeks for the first 2 months, then monthly for 4 months; following this, maintenance dosing practices varied depending on center. Baseline patient characteristics are given in Table 1. After bevacizumab initiation, patients with baseline anemia (Hgb<11, N=104) had an increase in mean Hgb from 8.6 g/dL to 11.9 g/dL at 3 months (P<0.0001) up to 12.5 g/dL at 12 months (P<0.0001) (Table 2, Figure 1). For patients with epistaxis as an indication for treatment (N=119), mean ESS dropped from 6.8 at baseline to ≤3.5 on treatment (P<0.0001) (Table 2, Figure 2). In patients requiring RBC transfusion prior to bevacizumab (N=81), transfusion requirements decreased from a median of 8 units in the 6 months before treatment to a median of 0 units in the first 6 months after treatment (P<0.0001); similarly, in patients requiring iron infusion prior to bevacizumab (N=99), requirements decreased from a median of 4 infusions to 2 infusions (P<0.0001) (Table 2). RBC transfusion and iron infusion requirements continued to improve with ongoing bevacizumab treatment (Table 2) and improvement occurred regardless of baseline bleeding severity; Figure 3 illustrates the dramatic reduction in RBC transfusion and iron infusion requirements in a severe patient sub-cohort. Overall, compared with pretreatment, RBC transfusion and iron infusion requirements decreased by 86% and 66%, respectively, on bevacizumab. On subgroup analysis by underlying mutation (ENG vs. ACVRL1), there were no significant differences in baseline parameters or bevacizumab response. Bevacizumab was well-tolerated; TEAEs felt to be likely or possibly related to bevacizumab occurred in 36% of patients (Table 3), with new or worsened hypertension (16%) and fatigue (9%) most common. No patient developed venous thromboembolism on bevacizumab. Only 5 patients (4%) discontinued bevacizumab for TEAEs and only 3 patients (2%) discontinued bevacizumab for lack of effectiveness. Conclusions : We present results of IV bevacizumab treatment of chronic bleeding and anemia in a large cohort of 140 HHT patients, demonstrating that bevacizumab was highly effective, with an improvement in mean Hgb of 3.9 g/dL, dramatic reduction in ESS, and decrease in RBC transfusion and iron infusion requirements by 86% and 66%, respectively. Effectiveness was maintained over time. Safety analysis included a total of 194 patient-years of IV bevacizumab administration to HHT patients and had low TEAE rates with only 4% discontinuing treatment due to TEAEs. Disclosures Al-Samkari: Agios: Consultancy, Research Funding; Moderna: Consultancy; Dova: Consultancy, Research Funding. Kuter:Caremark: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Dova: Consultancy, Honoraria; Kyowa-Kirin: Consultancy, Honoraria; Zafgen: Consultancy, Honoraria; Platelet Disorder Support Association: Consultancy, Honoraria; Shinogi: Consultancy, Honoraria; Up-to-Date: Consultancy, Honoraria, Patents & Royalties: 3 Up-to-Date chapters; Agios: Consultancy, Honoraria, Research Funding; Platelet Disorder Support Association: Consultancy, Honoraria; Bristol Myers Squibb (BMS): Consultancy, Honoraria, Research Funding; Caremark: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Merck Sharp Dohme: Consultancy, Honoraria; Merck Sharp Dohme: Consultancy, Honoraria; Daiichi Sankyo: Consultancy, Honoraria; Argenx: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb (BMS): Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Kezar: Research Funding; Shire: Consultancy, Honoraria; Kezar: Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Agios: Consultancy, Honoraria, Research Funding; Principia: Consultancy, Honoraria, Research Funding; Zafgen: Consultancy, Honoraria; Alnylam: Consultancy, Honoraria, Research Funding; Actelion (Syntimmune): Consultancy, Honoraria, Research Funding; Actelion (Syntimmune): Consultancy, Honoraria, Research Funding; Principia: Consultancy, Honoraria, Research Funding; Protalex: Consultancy, Honoraria, Research Funding; Protalix: Consultancy, Honoraria; Protalix: Consultancy, Honoraria; Rigel: Consultancy, Honoraria, Research Funding; Rigel: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; UCB: Consultancy, Honoraria; Takeda (Bioverativ): Consultancy, Honoraria, Research Funding; Up-to-Date: Consultancy, Honoraria, Patents & Royalties: 3 Up-to-Date chapters; UCB: Consultancy, Honoraria; Kyowa-Kirin: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Genzyme: Consultancy, Honoraria; Genzyme: Consultancy, Honoraria; Protalex: Consultancy, Honoraria, Research Funding; Argenx: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Shinogi: Consultancy, Honoraria; Takeda (Bioverativ): Consultancy, Honoraria, Research Funding; Shire: Consultancy, Honoraria; Alnylam: Consultancy, Honoraria, Research Funding; Dova: Consultancy, Honoraria; Daiichi Sankyo: Consultancy, Honoraria; Momenta: Consultancy, Honoraria; Momenta: Consultancy, Honoraria. OffLabel Disclosure: The presentation will discuss off-label use of systemic bevacizumab for the treatment of chronic bleeding and anemia in hereditary hemorrhagic telangiectasia.

Background: Immune thrombotic thrombocytopenic purpura (iTTP) is a potentially fatal hematologic disorder characterized by thrombocytopenia, microangiopathic hemolytic anemia, and ischemic organ impairment. The incidence of iTTP is higher among African-Americans (AA), however, differences in presentation and outcomes have not been fully investigated. In a multi-center cohort of patients with iTTP from the United States Thrombotic Microangiopathy (USTMA) Consortium, we tested the hypothesis that AA race is an independent predictor of poor outcomes including iTTP related mortality and relapse. Methods: We queried data from the USTMA iTTP registry, which currently includes data from 785 individual patients from 15 institutions across the United States. Data from at least one iTTP episode are available for 734 patients. The cohort is 35.1% (N = 272) White, 58.7% (N = 455) African American, 0.4% (N=3) Asian, 1.8% (N=14) Hispanic, and 4.0 % (N=31) other/unknown race. We restricted our analyses to AA and White participants because of small numbers in the other groups. We compared presenting features and treatments using the chi-squared test and t-test for categorical and continuous variables, respectively. A relapse was defined as a recurrent iTTP episode occurring at least 30 days after last therapeutic plasma exchange. To evaluate relapse-free survival, we included only patients enrolled in the registry at their first TTP episode (144 White and 246 AA) since patients presenting with a relapse as their index episode are already confirmed to have relapsing iTTP. Kaplan Meier analysis was used to compare relapse-free survival in White and AA patients, and a Cox regression model was developed to evaluate the independent effect of race on relapse, adjusting for potential confounders including age, sex, and the use of rituximab. Results: Demographics and presenting features of 390 individuals (144 White and 246 AA) presenting with a first episode of iTTP are shown in Table 1. Presenting symptoms including fever, confusion, seizure, memory deficits, stupor, headache, stroke, chest pain, abdominal pain, fatigue, and dark urine were similar between Whites and AA except for petechiae, which were more frequently documented in Whites (28.8% vs 17.7%, p=0.011). Presenting laboratory studies were also comparable though AA had a higher rate of elevated serum troponin (50.6% vs 32.5%, p=0.003), lower hemoglobin level (8.27 ± 0.13 vs 8.81 ± 0.19, p=0.0176) and platelet count (20.3 ± 1.2 vs 26.2 ± 3.2, p=0.0432). In addition to therapeutic plasma exchange and corticosteroids, rituximab was administered to 23.7% of White patients and 22.7% of AA during their first iTTP episode (P=0.815). Median time to platelet count recovery (days of daily plasma exchange until normal platelet count for two consecutive days) was shorter in AA compared with White patients [5 (IQR 4, 10) vs. 8 (IQR 5, 14), log rank P = 0.004]. AA race remained a significant predictor of the shorter time to platelet count recovery [HR 1.44 (95% CI 1.12, 1.85), P=0.004] after adjusting for rituximab therapy [HR 0.60 (95% CI 0.0.46, 0.80), P<0.001], female sex [HR 0.95 (95% CI 0.73, 1.22), P=0.669], age [HR 0.99 (95% CI 0.99, 1.01), P=0.682], platelet count [HR 1.00 (95% CI 0.99, 1.04), P=0.820] and LDH at presentation [HR 1.00 (95% CI 1.00, 1.00), P=0.525]. Death during the first episode occurred in 8.9% of White patients and 5.5% of AA patients (P=0.206). Relapse-free survival after the first episode of iTTP was lower in AA than White patients (Figure 1). AA race was associated with the reduced relapse free survival [HR 1.79 (95% CI 1.08, 2.98), P=0.024] in a Cox regression model adjusted for age [HR 1.00 (95% CI 0.98, 1.01), P=0.683], sex [HR 0.96 (95% CI 0.60, 1.54), P=0.867], and rituximab therapy [HR 0.93 (95% CI 0.55, 1.59), P=0.806]. Conclusion: African Americans with iTTP have a higher relapse rate and shorter relapse free survival after the first episode of the disease compared with Caucasian patients, which is independent of age, sex and rituximab therapy. Contrary to our hypothesis, acute outcomes of iTTP (time to platelet count recovery and mortality) were not worse in AA patients. The factors contributing to the higher relapse rate in AA with iTTP need to be further investigated. Our findings suggest that AA patients may also benefit from closer follow up. Disclosures Farland: Sanofi: Membership on an entity's Board of Directors or advisory committees. Metjian:Sanofi: Membership on an entity's Board of Directors or advisory committees. Raval:Bayer, Inc: Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees. Liles:Shire: Other: PI on clinical trial Sickle cell ; Imara: Other: PI on Clinical trial- Sickle cell ; Novartis: Other: PI on clinical trial Sickle cell . Baumann Kreuziger:CSL Behring: Consultancy; Vaccine Injury Compensation Program: Consultancy. McCrae:Dova Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Pfizer Pharmaceutical: Membership on an entity's Board of Directors or advisory committees; Rigel Pharmaceutical: Membership on an entity's Board of Directors or advisory committees; Sanofi Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Zheng:Alexion: Speakers Bureau; Ablynx/Sanofi: Consultancy, Speakers Bureau; Clotsolution: Other: Co-Founder; Shire/Takeda: Research Funding. Cataland:Alexion: Consultancy, Research Funding; Ablynx/Sanofi: Consultancy, Research Funding. Chaturvedi:Shire/Takeda: Research Funding; Sanofi: Consultancy; Alexion: Consultancy.