Annual incidence and severity of acute episodes in hereditary thrombotic thrombocytopenic purpura

• Published in: Blood Vol. 137; no. 25; pp. 3563 - 3575
• Main Authors: Tarasco, Erika, Bütikofer, Lukas, Friedman, Kenneth D., George, James N., Hrachovinova, Ingrid, Knöbl, Paul N., Matsumoto, Masanori, von Krogh, Anne Sophie, Aebi-Huber, Isabella, Cermakova, Zuzana, Górska-Kosicka, Magdalena, Jalowiec, Katarzyna A., Largiadèr, Carlo R., Prohászka, Zoltán, Sinkovits, György, Windyga, Jerzy, Lämmle, Bernhard, Kremer Hovinga, Johanna A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 24.06.2021
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.2020009801

Hereditary thrombotic thrombocytopenic purpura (hTTP) is a rare thrombotic microangiopathy characterized by severe congenital ADAMTS13 deficiency and recurring acute episodes causing morbidity and premature death. Information on the annual incidence and severity of acute episodes in patients with hTTP is largely lacking. This study reports prospective data on 87 patients from the Hereditary TTP Registry (clinicaltrials.gov #NCT01257269) for survival, frequency, and severity of acute episodes from enrollment until December 2019. The 87 patients, followed up for a median of 4.2 years (range, 0.01-15 years), had a median age at overt disease onset and at clinical diagnosis of 4.6 years and 18 years (range, 0.0-70 years for both), respectively. Forty-three patients received regular plasma prophylaxis, whereas 22 did not, and treatment changed over time or was unknown in the remaining 22. Forty-three patients experienced 131 acute episodes, of which 91 (69%) occurred in patients receiving regular prophylaxis. This resulted in an annual incidence of acute episodes of 0.36 (95% confidence interval [CI], 0.29-0.44) with regular plasma treatment and of 0.41 (95% CI, 0.30-0.56) without regular plasma treatment. More than one-third of acute episodes (n = 51) were documented in children <10 years of age at enrollment and were often triggered by infections. Their annual incidence of acute episodes was significantly higher than in patients aged >40 years (1.18 [95% CI, 0.88-1.55] vs 0.14 [95% CI, 0.08-0.23]). The prophylactic plasma infusion regimens used were insufficient to prevent acute episodes in many patients. Such regimens are burdensome, and caregivers, patients, and their guardians are reluctant to start regular plasma infusions, from which children particularly would benefit. •Annual incidence of acute episodes of hTTP is highest in children <10 years of age and decreases with increasing age.•Currently applied plasma prophylaxis is often not sufficient to prevent the occurrence of acute episodes of hTTP. [Display omitted]