Deviation from Guidelines in Use of Eltrombopag and Romiplostim in Clinical Practice for Children with Primary Immune Thrombocytopenia; Multi-Center Egyptian Experience

Background:

Primary immune thrombocytopenia (ITP) has been treated with steroids or immune-suppressive. Thrombopoietin receptor agonists (TPO-RAs), changed the treatment landscape for ITP. Romiplostim and Eltrombopag were FDA approved for use in pediatric patients ≥1 year with ITP of >6 months' duration and insufficient response to previous therapy. Following the guidelines is not always feasible in practice.

Aim and Methodology

Centers treating more than 25 new cases/year with good recording system were included; aiming to report outcome, adverse events (AEs) and deviation from guidelines. Newly diagnosed ITP children were excluded. Data was collected from January 2017- June 2019; children age >1 to 18 years with persistent ITP (3-<12 months) or chronic (≥12 months), who had previously been treated with ≥1 previous ITP therapy, and had platelet counts (PC) persistently <30×10⁹/l with moderate-severe bleeding. Eltrombopag was described in a dose of 25 mg/day for those > 1 to 12 years; or in 50 mg/day for those >12-18 years; dose was escalated to 50 or 75mg/day for those 6-12 and >12 years respectively on failure to have PC > 50 x 10⁹/L. Weekly CBC and self-record of bleeding for 1^st 24 week then bi-weekly. Failure to show a good response; Eltrombopag dosing should be adjusted to achieve that goal and not to exceed 200 × 10⁹/L. Romiplostim was used in 1 ug/kg and escalated up to 10 ug/kg according to response. Serious AEs were reported to ethical committee within 24 hours.

Results

Two years Observational study of 204 out of 1080 primary ITP (268 persistent and 812 chronic); 55% females median age 8 years, received Eltrombopag (n=186), Romiplostim (n= 18) from 3-30 months was prescribed after failure of 1-5 lines of therapy in 15% of Persistent ITP and 20% of chronic ITP. Adequate response at 24 weeks in 60% on Eltrombopag or Romiplostim had a significant reduction in both skin-related and non-skin-related bleeding symptoms). However 50% discontinued treatment; (40% due to inadequate response, 8% irregular availability and 2% due to SAEs). Deviation from guidelines in 40%; (15% started Eltrombopag early between 3-6 months who showed a higher response rate; half of them could stop it without drop of PC); while 20% continued Eltrombopag for >12 month with lack of response after dose escalation at 24^th week and 5% were not following the described dose or the regular monitoring. 40% of chronic ITP patients achieved platelet counts of >50 x 10⁹/L or more at least twice. Common adverse events included; headache (10%). myalgia (10%), rhinitis (8%), diarrhea 8% Serious adverse events occurred in 4 (1 elevated transaminases, one unrelated life-threatening bleeding and two high PC; >1000 x10⁹/L).

Conclusion: TPO-RAs were used in almost 15% of persistent and 20% of chronic ITP as 2^nd line or more therapy and in 90% was Eltrombopag; which produced an excellent response for those 3-6 months; deviating from guidelines. It showed a sustained platelet response in 40% of patients with chronic ITP, however it should be stopped if showing poor response after dose escalation.