Pediatric refractory chronic immune thrombocytopenia: Identification, patients' characteristics, and outcome

Abstract

Refractory chronic immune thrombocytopenia (r‐cITP) is one of the most challenging situations in chronic immune thrombocytopenia (cITP). Pediatric r‐cITP is inconsistently defined in literature, contributing to the scarcity of data. Moreover, no evidence is available to guide the choice of treatment. We compared seven definitions of r‐cITP including five pediatric definitions in 886 patients with cITP (median [min‐max] follow‐up 5.3 [1.0–29.3] years). The pediatric definitions identified overlapping groups of various sizes (4%–20%) but with similar characteristics (higher proportion of immunopathological manifestations [IM] and systemic lupus erythematosus [SLE]), suggesting that they adequately captured the population of interest. Based on the 79 patients with r‐cITP (median follow‐up 3.1 [0–18.2] years) according to the CEREVANCE definition (≥3 second‐line treatments), we showed that r‐cITP occurred at a rate of 1.15% new patients per year and did not plateau over time. In multivariate analysis, older age was associated with r‐cITP. One patient (1%) experienced two grade five bleeding events after meeting r‐cITP criteria and while not receiving second‐line treatment. The cumulative incidence of continuous complete remission (CCR) at 2 years after r‐cITP diagnosis was 9%. In this analysis, splenectomy was associated with a higher cumulative incidence of CCR (hazard ratio: 5.43, 95% confidence interval: 1.48–19.84, p = 7.8 × 10−4). In sum, children with cITP may be diagnosed with r‐cITP at any time point of the follow‐up and are at increased risk of IM and SLE. Second‐line treatments seem to be effective for preventing grade 5 bleeding. Splenectomy may be considered to achieve CCR.