The use of rituximab for autoimmune thrombotic thrombocytopenic purpura (iTTP) did not significantly reduce acute iTTP relapses, according to data published in Cellular Haemostasis and Platelets.1
Because of the risk of relapse associated with iTTP, researchers sought to determine what factors may influence this occurrence and potential therapeutic options to decrease this risk via a retrospective observational study.
The researchers evaluated 70 patients who were treated between January 2003 and November 2014 and collected information regarding their acute episodes including number, duration, clinical manifestations, laboratory data, and treatment.
“Acute episodes are characterized by consumptive thrombocytopenia, micro-angiopathic haemolytic anaemia (MAHA) and spontaneous von Willebrand factor (VWF)-induced platelet clumping,” the researchers wrote. “A severe a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13 (ADAMTS13) deficiency (< 10%) due to autoantibodies against ADAMTS13 is associated with acute episodes.”
The median observation period for this study was 8.3 years, during which time 224 acute episodes were observed in 54 female patients and 16 male patients. Of all the patients involved in the study, 59% had at least 1 relapse regardless of whether rituximab was added or not (outside of their use of rituximab in acute episodes).
The relapse rate was 2.4% and 3.5% per month for female patients and male patients, respectively. Since 2003, the first time off-label rituximab was administered, 17 patients were treated with the drug and 28 were not. While the researchers found a trend toward lower relapse rates in patients who were treated with rituximab over time, this trend was not found to be statistically significant (P = .729).
This research was the first large German cohort of patients with iTTP that looked into the factors that may influence relapse rates. In addition to the findings regarding treatment and relapse, the research also shed light on the differences in acute episodes between men and women, in that men experienced more serious events.
- Falter T, Herold S, Weyer-Elberich V, et al. Relapse rate in survivors of acute autoimmune thrombotic thrombocytopenic purpura treated with or without rituximab [published online September 20, 2018]. Thromb Haemost. doi: 10.1055/s-0038-1668545