Clinical manifestations, treatment characteristics, and clinical outcomes in patients with immune thrombotic thrombocytopenic purpura (ITTP) in a real-world setting: An interim analysis of the Turkish ITTP registry

Abstract

Objective: This study aimed to investigate the clinical manifestations, treatment patterns, and clinical outcomes of patients with immune thrombotic thrombocytopenic purpura (iTTP) across T & uuml;rkiye via an interim analysis of the Turkish iTTP Registry.<br /> Materials and Methods: A total of 215 patients with iTTP (median age at diagnosis: 41 years; 58.6% female) diagnosed between 2001 and 2023 were retrospectively analyzed in the interim analysis of a prospective non-interventional observational multicenter iTTP registry study (ClinicalTrials.gov Identifier: NCT05950750) conducted at 19 tertiary hematology centers. Data on patient demographics, disease characteristics at initial admission, treatment characteristics and responses, exacerbations/relapses, and survival outcome were obtained from electronic case report forms.<br /> Results: Infection (15.0%), new drug initiation (9.7%), and pregnancy/ postpartum period (6.3%) within 3 weeks before diagnosis were the most prevalent potential triggers. Patients presented most commonly with systemic/constitutional (fatigue: 68.8%; fever: 18.1%) and neurological (headache: 40.0%; vertigo: 32.1%) symptoms, followed by hemorrhagic, gastrointestinal, renal, and cardiovascular manifestations. Based on PLASMIC risk scoring, 77.8% of patients were initially at high risk for TTP. The initial treatment was begun within the first 48 hours of hospital admission for 64.1% of patients (36.2% on the day of admission). Treatment was mainly based on therapeutic plasma exchange (92.1%) and steroids (63.7%), while rituximab was used in 15.8% of patients. The clinical response rate was 79.9% and clinical remission was achieved by 68.2% of patients. Regarding a thrombospondin type 1 motif member (ADAMTS13) 13 levels, partial and complete responses were achieved by 17.7% and 14.6%, respectively. During a median of 30 months (range: 0.1-262.4 months) of follow-up, 35 patients experienced exacerbations/relapses. Mortality occurred in 11 (5.5%) patients and was found to be disease-related in 6 cases (3.0%). Conclusion: This interim analysis of the nationwide Turkish iTTP Registry study provides valuable data on real-world clinical practices in the diagnosis and management of iTTP at different hematology clinics across the country.