Chronic refractory immune thrombocytopenia in adolescents and young adults.

Defining immune thrombocytopenia (ITP) in two age groups-children and adults-overlooks the specific clinical features and needs of adolescents and young adults (AYAS). We previously reported a high risk of chronic disease at 12 months (50%); however, data on the course of chronic ITP, the risk of refractoriness and treatment strategies in AYAS are limited. Data from patients aged 12-25 years with chronic primary ITP at 12 months were extracted from three large registries between 2004 and 2021. Clinical and laboratory data were evaluated until 48 months of follow-up (FU). Refractory ITP was defined as the administration of ≥3 different lines of therapy. A total of 427 AYAS (64% female) with chronic ITP were included. Overall, 7% and 14% were classified as 'refractory' at 12 and 48 months of FU respectively. The proportion of males was greater in the refractory group than in the non-refractory group (43% vs. 35%). AYAS with refractory disease displayed lower median platelet counts, more bleeding and a higher need for treatment at initial diagnosis and FU than non-refractory patients. This study reveals that refractory ITP is uncommon in AYAS; however, AYAS with refractory ITP display a high disease burden at all time points, including at initial diagnosis.

Adolescents and young adults with newly diagnosed primary immune thrombocytopenia.

Current immune thrombocytopenia (ITP) guidelines target children and adults, leading to oversimplification. Adolescents and young adults (AYAS) comprise a separate group with distinct health and psychosocial issues. This study aimed to describe the clinical presentation and therapeutic strategies of ITP among AYAS. We analyzed data from two large ITP registries (PARC-ITP; CARMEN-France) and included newly diagnosed ITP patients (aged 12-25 years) with an initial platelet counts of <100×109/L. Patients with secondary ITP or non-immune thrombocytopenia (n=57) and pregnant women (n=10) were excluded. Of the 656 cases of AYAS with primary ITP registered from 2004 up to 2021, 12-month follow-up data were available for 72%. The initial median platelet count was 12×109/L. In 109 patients (17%), the diagnosis was incidental, without documented bleeding. Apart from gynecological bleeding, the clinical and therapeutical characteristics of females and males were similar. Platelet-enhancing drugs were reported in 66%, 45%, and 30% of patients at diagnosis, 1-6 months, and 6-12 months after diagnosis, respectively. Corticosteroids were the preferred treatment at all time points. At 12 months, 50% of all patients developed chronic ITP. In the subgroup of patients with initial severe thrombocytopenia (<20×109/L), those receiving frontline treatment had a higher remission rate at 1 year than those who followed an initial watch-and-wait strategy (53% and 32%; P<0.05). Our analysis indicates that the remission rate at 1 year may be associated with the initial treatment strategy. This hypothesis must be confirmed in prospective studies.