According to results from a study recently published in Blood Advances, non-O blood group, age younger than 25 years, and presentation with immune-mediated thrombotic thrombocytopenic purpura (iTTP) relapse were all independently associated with increased risk for subsequent relapse. Additionally, treatment with rituximab conferred protection from relapse at 1 year of follow-up.
Patients with iTTP frequently experience life-threatening relapses of the disease. Rituximab can decrease relapse risk. This study sought to elucidate other factors affecting risk of relapse by assessing 124 consecutive patients with iTTP, 60 of whom received rituximab and 34 of whom experienced relapse.
Median time to relapse was 3.71 years (interquartile range [IQR], 1.75-4.9) in patients treated with rituximab and 1.33 years (IQR, 0.43-2.35) in patients not treated with rituximab. Although treatment with rituximab conferred protection from relapse at 1 year of follow-up (P =.01), that protection did not persist at 5 years of follow-up. The initial protection against relapse conferred by rituximab (hazard ratio [HR], 0.16; 95% CI, 0.04-0.70) returned to baseline levels of no benefit at approximately 2.6 years.
Age less than 25 years (HR, 2.94; 95% CI, 1.2-7.2), presenting in relapse (HR, 2.97; 95% CI, 1.4-6.4), and non-O blood group (HR, 2.15; 95% CI, 1.06-4.39) were found to independently associate with a greater risk for subsequent relapse.
“[W]e report 3 clinical parameters predictive of relapse that, if validated in other cohorts, may help identify patients who should be followed more closely or in whom more aggressive disease-modifying therapy could be employed,” the authors wrote.
Sun L, Mack J, Li A, et al. Predictors of relapse and efficacy of rituximab in immune thrombotic thrombocytopenic purpura [published online May 10, 2019]. Blood Adv. doi:10.1182/bloodadvances.2019031039