Eltrombopag appears to be a safe and effective second-line therapy for pediatric patients with immune thrombocytopenic purpura (ITP); however, standardized dosing, as well as tapering and discontinuation, is still required, according to a recently published study in Hematology.
All guidelines recommend eltrombopag along with romisplostim for pediatric cases of ITP where second-line therapy is required. Therefore, the authors aimed to do a review regarding the evidence supporting the use of eltrombopag as second-line therapy with a focus on dosing, tapering, and discontinuation.
The pediatric dose of eltrombopag is currently based on age rather than weight which raises the risk of underexposure in older patients and overexposure in younger ones. Furthermore, evidence suggests that children under the age of 11 have a higher area under the curve (AUC) and Cmax than the general population, thus increasing the risk of overexposure in this population.
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Some studies show that the half-life of eltrombopag appears to be very variable in some patients, thus creating a need for a more detailed pharmacokinetic study that could lead to dosing modification and splitting.
Studies regarding the clinical efficacy of eltrombopag have shown that the overall response rate to eltrombopag in the pediatric population is over 75%. The rate of adverse effects is around 6% comprised mostly of mild or moderate adverse effects such as headache and thrombocytosis that rarely lead to treatment discontinuation.
There are currently no recommendations regarding the appropriate duration of eltrombopag treatment. However, due to the limited data on the long-term effects of the drug, discontinuation should be considered after achieving a persistent response.
A recent study published in the UK suggested that patients with an adequate response to treatment for over 12 months should be considered for discontinuation. However, treatment should be reinitiated if platelet levels fall below 30.000/ml. The same study proposed a tapering scheme consisting of daily 25% reductions for 4-week intervals.
“There is currently very limited data about the effects of the drug, especially toxicity, when administered to pediatric patients in the long term.” The authors wrote, “This, together with other considerations such as the high rate of spontaneous remission and costs, makes it worth attempting to taper/discontinue the TPO-RA.”
Reference
Palumbo G, Farruggia P, Ramenghi U, et al. Pediatric immune thrombocytopenia: A focus on ELTROMBOPAG as second-line therapy. Hematology. Published online May 18, 2023. doi:10.1080/16078454.2023.2210906
