Bandarenko, Nicholas

Abstract SERF-TTP is the first prospective case-control study to investigate epidemiology, risk factors & outcomes in patients with first episode of idiopathic TTP. METHODS: Each case of TTP is identified upon referral for therapeutic plasma exchange (TPE). Exclusion criteria include organ or allogeneic stem cell transplant, anti-neoplastic therapy or malignancy. 2 age & gender-matched controls are identified for each case. Epidemiologic information, lab data & plasma samples are collected from each case. Case & control data are collected by standardized interview. Relative risk & 95% CI computed by chi-squared tests. ADAMTS13 activity & inhibitor are centrally measured on pre-TPE samples. ADAMTS13 activity is measured by FRETS-vWF73 assay (Peptides Int.). ADAMTS13 inhibitor is assessed by Technozym ADAMTS13 INH ELISA (Technoclone). RESULTS: Data is available for 67 cases & 138 controls. The median age of cases is 40, & 82% are female. Medical history & exposures are shown in Table 1. Clinical & lab characteristics vary by ADAMTS13 activity (Table 2). Low titer ADAMTS13 inhibitors are detectable in some patients with normal ADAMTS13 activity. 30 day survival of cases is 95.7%. Adverse reactions to TPE occur in 59% of patients, most commonly allergic(85%) or citrate-related reactions(65%). 14.7% had a venous access complication, 50% were catheter-related thromboses. 10% of all adverse events required an ICU admission. CONCLUSIONS: Preliminary results from the case-control study suggest that predisposing factors for the development of TTP include recent infection or connective tissue disorder. Cardiovascular disease, prior history of venous thrombosis, clopidogrel use and lower income are more common in TTP cases than controls. Patients with normal ADAMTS13 activity are more likely to present with higher platelet count, abnormal renal function and neurologic symptoms. Case & Control Characteristics Cases (n=67) Controls (n=138) Relative Risk (95% CI) Medical History Connective Tissue Disease 11.9% 2.2% 5.4 (1.5–20.0) Cardiovascular Disease 13.4% 3.6% 3.7 (1.29–10.6) Prior Venous Thrombosis 13.4% 2.9% 4.6 (1.48–14.5) Infection (prior 2 wks) 32.8% 10.1% 3.2 (1.77–5.9) Medications (prior 12 wks) Antibiotics 31.3% 17.4% 1.8 (1.08–2.99) Clopidogrel 4.5% 0.7% 6.4 (0.65–62.9) Income Level < $25,000 42% 18% 2.3 (1.47–3.6) $25,000 – 70,000 37.3% 52.9% 0.7 (0.49–0.99) > $70,000 11.9% 24.6% 0.5 (0.24–0.98) Characteristics by ADAMTS13 activity ADAMTS13 activity N ADAMTS13 inhibitor (>15 u/ml) ADAMTS13 inhibitor titer (mean) Platelets (mean) Creatinine (mean) Neurologic symptoms Survival Comparison of ADAMTS13 ≤20% vs > 20%, p-values: * 0.0028, † 0.003, ‡ 0.73, # 0.48. < 5% 18 (37.5%) 100% 80.9 22,350 1.4 44% 94% 5–20% 4 (8.3%) 100% 76.4 20,000 1.1 75% 100% > 20% 26 (54.2%) 57.7% 22.5 58,810* 4.3† 58%‡ 89.5%#

Abstract Background : Many idiopathic thrombotic thrombocytopenia purpura (TTP) patients have severe deficiency of ADAMTS13, an enzyme that cleaves ultralarge von Willebrand multimers. We recently reported that thienopyridine-associated TTP is characterized by an immunologic pathway with severe ADAMTS13 deficiency and a non-immunologic pathway with higher ADAMTS13 activity levels. We now compare findings for idiopathic and thienopyridine-associated TTP patients. Methods : Clinical findings and laboratory findings were evaluated for 51 idiopathic and 39 thienopyridine-associated TTP. Results: Clinical findings were similar between idiopathic and thienopyridine-associated TTP for both severe ADAMTS13 deficient and non-deficient patients. Differences were noted in gender and age, relapse rates, and survival. Conclusion : Among TTP patients with ADAMTS13 deficiency, relapses are frequent in idiopathic TTP patients and Rituximab may be useful, while for thienopyridine-associated TTP patients spontaneous relapse are rare as long as no re-exposure occurs. Among ADAMTS13 non-deficient patients, survival is high following therapeutic plasma exchange (TPE) for idiopathic patients but not for thienopyridine-associated TTP patients. Despite similarities, idiopathic and thienopyridine associated TTP probably have different initiating factors. ADAMTS13 activity and clinical characteristics in idiopathic and thienopyridine-associated TTP Idiopathic severe ADAMTS13 deficiency (n=29) †Thienopyridine severe ADAMTS13 deficiency (n=26) Idiopathic non-severe ADAMTS13 deficiency (n=22) †Thienopyridine non-severe ADAMTS13 deficiency (n=13) *p<0.05 for comparison of severe ADAMTS13 deficiency versus non-severe ADAMTS13 deficiency. †Thienopyridine-associated TTP clinical and presenting neutralizing autoantibody data was summarized from the Journal of the American College of Cardiology publication by Bennett et al. in 2007. ‡Thienopyridine-associated TTP remission autoantibody data was summarized Tsai et al, 2002, Bennett et al, 2000, and Orimo et al, 2002, and included 3 patients. §Data from average of ADAMTS13 deficient and non-deficient cohorts. Mean Age 41 67 47 60 Sex (% female) 79% 54% 86% 39% Platelet count/mm3 (mean)* 18,978 9,269 51,409 35,000 Platelet count <20,000/mm3* 69% 96% 23% 38% Hemoglobin (mg/dl; mean) 8.5 8.3 9.0 8.4 Creatinine (mg/dl; mean)* 1.5 2.2 3.2 3.0 Creatinine >2.5 mg/dl* 11% 27% 48% 46% 30-day survival 96% 85% 90% 62% Long-term relapse* 42% 8% 0% 0% Neutralizing autoantibodies to ADAMTS13 (prior to TPE) § 79% 100% 27% 0% Neutralizing autoantibodies to ADAMTS 13 (measured at remission) § 55% 33%‡ 33% 0%

Abstract Background: Thrombotic thrombocytopenic purpura (TTP) is a rare disorder that presents with microangiopathic hemolytic anemia and thrombocytopenia, fevers, renal insufficiency and neurologic features. We reviewed clinical, laboratory, and outcome data for TTP cases with severely deficient versus non-severely deficient ADAMTS13 activity levels. Methods: Mean and median data were from the Surveillance, Epidemiology and Risk Factors for TTP (SERF-TTP) study group for idiopathic TTP cases, the Canadian Apheresis Group (CAG), and five published series (Zheng 2004, Raife 2004, Vesely 2003 (Oklahoma TTP-HUS Registry), Matsumoto 2004 (Japan Referral Center), Bennett 2007). Results: Compared to TTP cases with near-normal ADAMTS13 activity levels (n= 282), TTP cases with severe ADAMTS13-deficiency (n=185) were more likely to have severe thrombocytopenia, normal renal function and neutralizing ADAMTS13 antibodies. Severe ADAMTS13 deficient TTP cases have better overall survival after therapeutic plasma exchange (TPE) but are more likely to relapse. TTP patients with severe ADAMTS13 deficiency were primarily categorized as idiopathic or ticlopidine-associated, while TTP patients with non-severely deficient ADAMTS13 activity levels were frequently categorized as idiopathic, secondary to drugs (clopidogrel, quinine), stem cell transplantation, or cancer. Conclusions: Severe ADAMTS13 deficiency is most commonly idiopathic, has better survival following TPE, and a 35–40% spontaneous relapse rate. By contrast, non-ADAMTS13 deficient TTP cases are usually associated with an underlying disorder or external insults. Amongst this cohort, four series have 47–62% survival rates and three series, which contain mostly idiopathic cases, have 83–90% survival rates following TPE. From this, we propose that TTP may occur by three possible mechanism; ADAMTS13-deficient (antibody-mediated), an immunologic mediated pathway independent of ADAMTS13 (i.e. quinine) that is responsive to TPE, and endothelial injury related TTP that is unresponsive to TPE. Platelet count mean (x10^9/L) Creatinine mean (mg/dl) ADAMTS13 neutralizing antibodies (%) Survival % Relapse % * <15% ADAMTS13 activity cutoff Severe ADAMTS13 Deficiency (<10–15%) SERF-TTP (n=30) 19 1.3 83 97 41 Zheng (n=16) 19 1.6 44 81 38 Bennett (n=26) 15 85 Oklahoma (n=18) 12 1.8 94 81 38 Raife (n=50) * 13 1.2 92 35 Japan (n=34) 35 91 Canada (n=11) 16 2.4 82 Not Severely Deficient ADAMTS13 Activity (> 15%) SERF-TTP (n=22) 57 3.9 35 90 0 Raife (n=57) * 44 2.7 83 9 Canada (n=17) 57 4.1 88 Zheng (n=13) 40 3.0 0 54 Bennett (n=13) 62 Japan (n=66) 9 62 Oklahoma (n=94 ) 23 47 3

Abstract Abstract 2203 Background: Thrombotic thrombocytopenic purpura (TTP) is frequently characterized by severe ADAMTS13 deficiency, the cause of which is unknown. An important exception is ticlopidine-associated TTP (tc-TTP), the most common drug-induced TTP syndrome. In 1998, a possible association of TTP with ticlopidine was reported. In 1999, two additional series reported this association. In 2000, a fourth study reported severe A DAMTS13 deficiency among six of seven tc-TTP persons- suggesting a causal pathway. All of these reports were from the United States. Recently, we reported characteristics of 186 acquired idiopathic (ai)- TTP patients in Japan with severe ADAMTS13 deficiency, noting that clinical and laboratory findings for ai-TTP patients in Japan differed from those for cohorts of ai-TTP patients in Europe and North America- raising concern that TTP findings vary by region of the world. (PLOS One 2011) We now on report clinical and laboratory characteristics of a cohort of TTP patients from Japan with tc-TTP, and compare these findings to three cohorts of tc-TTP in the United States and one cohort of ai-TTP patients from Japan. Methods: We queried a database of thrombotic microangiopathy patients identified from a national TTP referral laboratory in Japan of cases identified between 1998 and 2008. Severe ADAMTS13 deficiency was characterized by activity levels < 5%. All tc-TTP patients and 186 of 911 ai-TTP patients in the database had severe ADAMTS13 deficiency and first onset of TTP. Comparisons were made to tc-TTP patients reported previously from the United States. Results: Characteristics of ai- TTP with severe ADAMTS13 deficiency in Japan and tc-TTP in Japan and US Conclusions: These data from Japan validate insights about tc-TTP initially proposed in 1998, 1999, and 2000 in the United States. Ticlopidine is a likely cause of TTP, the mechanism is via a cross-reactive antibody to ADAMTS13:AC resulting in formation of an ADAMTS13:INH, and therapeutic plasma exchange is necessary for treatment. Disclosures: Ortel: Eisai: Research Funding; Glaxo SmithKline: Research Funding; Pfizer: Research Funding; Instrumentation Laboratory, Inc: Consultancy, Research Funding; Boehringer Ingelheim: Consultancy. Fujimura:Baxter BioScience: Membership on an entity's Board of Directors or advisory committees; Alexion Pharma: Membership on an entity's Board of Directors or advisory committees.