Abstract Number: OC 07.4
Meeting: ISTH 2020 Congress
Background: Severe deficiency of ADAMTS13 activity resulting from autoantibodies is the primary cause of immune thrombotic thrombocytopenic purpura (iTTP). Approximately 30% of iTTP patients (pts) may experience disease exacerbation and/or relapse. However, a reliable biomarker that predicts disease recurrence is still lacking.
Aims: The present study investigated the role of ADAMTS13 activity in predicting recurrence of iTTP.
Methods: The German Federal Ministry of Education/Research (BMBF) supported our registry, approved by the Ethics Committee. Pts with written informed consent were consecutively enrolled (acute bout or remission). Prospective follow up with ADAMTS13 activity measurement was planned at 3-month-intervals. The predictive value of ADAMTS13 activity was assessed using Cox regression.
Results: From 07/2016 to 12/2019, 103 iTTP- pts were enrolled and followed for 140-1271 days (median 1041), 85 (20-86 yrs, 64 female) had at least two visits. 13 Pts relapsed. During observation period 44/85 pts had continuously normal ADAMTS13 activity (≥50%), none of them relapsed. 2 Pts had ADAMTS13 activity continuously between 25-50%, none relapsed. One patient hat ADAMTS13 activity continuously between 10-25% and did not relapse. 9 pts had ADAMTS13 activity continuously < 10%, 8 relapsed so far. 30 Pts had undulating parameters of ADAMTS13 activity and did not relapse. 10/85 pts showed a steep decline of ADAMTS13 activity, 5 relapsed. 4 received preemptive rituximab. A reduction by at least a factor 2 within 3 months (values ≥50% to < 50%) showed a strong association with occurrence of relapse (HR = 11.26 95% CI 3.66-34.62, p< 0.0001). Baseline ADAMTS13 activity, age and sex were not found to be significantly associated with relapse.
Conclusions: Longitudinal quarterly assessment of ADAMTS13 activity is of critical value for predicting iTTP recurrence. These results suggest the need for additional off-label therapeutic coverage (rituximab, corticosteroids, caplacizumab) to prevent recurrence in the long-term management of patients with iTTP.
To cite this abstract in AMA style:von Auer-Wegener C, Schmidtmann I, Bach L, Hehmann M, Falter T, Rossmann H, Jurk K, Conradi R, Marandiuc D, Scharrer I, Lämmle B, Theobald M. Longitudinal Assessment of ADAMTS13-activity Helps Predict Recurrence of Immune Thrombotic Thrombocytopenic Purpura (iTTP): Results from the German TTP-registry [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/longitudinal-assessment-of-adamts13-activity-helps-predict-recurrence-of-immune-thrombotic-thrombocytopenic-purpura-ittp-results-from-the-german-ttp-registry/. Accessed November 27, 2021.
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