Response to First Line Treatment in Childhood ITP

Background

Immune thrombocytopenia is an idiopathic disorder of platelet destruction, characterised by mucocutaneous bleeding episodes and platelet count <100x10⁹/L. The majority of paediatric patients will spontaneously recover with conservative management. A minority require treatment for bleeding, usually occurring at a platelet count of <20x10⁹/L.

Objective

Comparison of patient groups by: treatment received, demographics, presentation, disease phase and time to platelet count >50x10⁹/L.

Method

1043 patients were identified from the UKITP Registry data from January 2007-May 2016

Results

798 patients were untreated other than supportive care. 245 patients (23%) had 422 treatment episodes for bleeding episodes. 42% of these were clinically mild (grade 1), 51% moderate (grade 2) and 7% severe (grade 3) or life-threatening (grade 4). 15% of patients with mild bleeding received treatment, 35% moderate, 84% severe and 100% life-threatening. 2 patients had intracranial bleeding.

The clinical severity of bleeding is positively associated with number of bleed sites. The untreated group were on average older, with a higher platelet count and milder presentation. 136 treatments were with IVIG, 92 steroid 1-2mg/kg/day (Regimen 1) and 60 with steroid 4mg/kg/day for 4 days (Regimen 2). 71 treatments were with combination therapy. No significant difference was found between platelet count of treated and untreated groups over first 3 months Regimen 2 produce a faster, but transient rise in platelet count compared to Regimen 1.

Steroids were more likely to be used for mouth bleeding and menorrhagia compared to IVIG and combination therapy. Lower GI bleeds demonstrate more IVIG and combination therapies. Macroscopic haematuria cases received more steroid Regimen 1 than other therapies. With increasing duration of disease the frequency of treatment was reduced from 261 treatments per 100 days (newly diagnosed) to 3 treatments per 100 days (chronic disease).

The greatest platelet increase was observed following IVIG or combination therapy with a median platelet count 37x10⁹/L by day 3 (IVIG) and 43x10⁹/L (combination) and 61x10⁹/L by day 5 (IVIG) and 90x10⁹/L (combination). A median platelet count maintained >30x10⁹/L to week 6 (IVIG) and week 8 (combination). In contrast both steroid regimens took until d5 to achieve a platelet response which was maintained until week 4 (regimen 1) and week 6 (regimen 2).

Conclusion

Currently 23% of children with ITP are receiving treatment in the UK. A higher proportion required treatment with increasing bleeding severity and number of bleeding sites. IVIG demonstrated a superior response to steroid therapy and should be considered preferable for more significant bleeding. A higher dose, short duration steroid regimen was associated with a better response compared to lower dose treatment and is preferable for milder bleeding that requires therapy.