Among patients with immune thrombocytopenia (ITP) treated with eltrombopag, it is possible to achieve sustained remission off-treatment (SROT), although markers indicating response likelihood must be accounted for, according to research published in the British Journal of Haematology.
Thrombopoietin mimetics, including eltrombopag, have been used in ITP treatment for the past 2 decades, and can yield a long-term response rate of up to 60%. Eltrombopag appears, furthermore, to have iron chelation effects, and may have immunomodulatory consequences, which together may help to explain why nearly one-third of patients who respond to eltrombopag have an SROT.
Given there is evidence that chronic ITP leads to greater immune dysregulation, early treatment with thrombopoietin mimetics such as eltrombopag may help to improve immune function. For this phase 2 study, researchers evaluated the effects of second-line eltrombopag, given for a definite time period, among patients with newly diagnosed or persistent primary ITP. The primary endpoint was SROT, defined as maintaining a response over a 6-month observation period after tapering and discontinuing eltrombopag.
Between 2016 and 2018, 51 patients with ITP were enrolled. The median patient age was 65 years (range, 21-90), 20 patients were male, and the median time from diagnosis to eltrombopag initiation was 18.2 weeks (range, 1.3-52). All patients received eltrombopag for 24 weeks.
Overall, 13 (25%) patients and 13 of 34 (38%) patients who started eltrombopag tapering reached SROT. Thrombopoietin levels at baseline did not predict a response at week 24 or SROT. Higher levels of interleukin-10, interleukin-4, and tumor necrosis factor–alpha at baseline all significantly and negatively predicted response.
“In conclusion, our study confirms that SROT may be achieved in some patients with ITP treated with eltrombopag,” the authors wrote. “It gives some insights into the biology of the disease and paves the way for seeking clinical and biological factors predictive of response.”
Disclosures: Some authors have declared affiliations with or received funding from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.
Lucchini E, Palandri F, Volpetti S, et al. Eltrombopag second-line therapy in adult patients with primary immune thrombocytopenia in an attempt to achieve sustained remission off-treatment: results of a phase II, multicentre, prospective study. Br J Haematol. Published online February 22, 2021. doi:10.1111/bjh.17334