Dose Adjustment and Use of Alternative Eltrombopag Dosing Regimens for the Treatment of Patients with Chronic Immune (Idiopathic) Thrombocytopenic Purpura (ITP)

Recently, the therapeutic approach of patients with chronic refractory thrombocytopenic purpura has dramatically improved since the adoption, as second-line treatment, of two new thrombopoietin receptor agonists, Eltrombopag and Romiplostim.

Purpose: Reporting the experience of our Center on the efficacy, dosing regimens and safety of the administration of Eltrombopag in refractory ITP patients.

Material and Methods: We studied retrospectively 300 patients in our Center with a diagnosis of ITP. One hundred eighty five patients were classified as refractory ITP after multiple cycles of treatment. Fourteen patients with refractory ITP were treated with Eltrombopag during the last two years. We studied dose adjustment, the time to response and duration of response as well adverse events. A partial response (PR) was defined as achieving a platelet count of ≥ 50×10³/ml, while a complete response (CR) as achieving a platelet count of ≥ 150 × 10³/mL.

Results: The patients were six men and eight women with a median age of 68.5 years (39.0 to 84.0 years). These patients had tried and failed numerous previous treatment regimens (2 to 8), including 6 patients who had received the thrombopoietin receptor agonist Romiplostim, 2 patients with splenectomy, as well as 2 patients in PR, who needed a higher platelet count due to concomitant disease. The median time from ITP diagnosis to Eltrombopag administration was 20.5 months (0.3 to 235.9 months) and the initial median platelet count was 34×10³/mL. Twelve out of 14 patients (12/14 ) responded (85.71%), 10 CR (71.42%) and 2 PR (14.29%) with a mean platelet count of 294 × 10³/mL (an increase of 260.5 x10³/mL). The median time to response was 17 days (5–64 days) and the response was durable in 9/ 10 patients (90%). Forty per cent of patients required a dose increase at the Day 22 visit. The starting dose was 25mg once daily of Eltrombopag and administered over 6 cycles. If the patientxs platelet number was >200 x10³/mL the treatment was interrupted. The next cycle started when the patient's platelet count was <20 x10³/mL. The dose of Eltrombopag was increased to 75mg daily when a patient's platelet count remained < 50 x10³/mL. The number of patients who had Eltrombopag dose increases to 75mg were 3 (21%), 2(14%) and 2 (14%) in cycles 1, 2 and 3, respectively. One patient (7%) experienced a serious side effect such as thromboembolic disease (right leg deep venous thrombosis and pulmonary embolism).

Conclusions: Despite the small number of patients in this study, our results agree with those of similar large studies from other Centers. Since Eltrombopag is an oral therapy and does not require hospitalization, is an easy, effective, alternative therapy, which improves the quality of life of patients with refractory ITP. In most cases dose adjustment and use of alternative Eltrombopag dosing regimens is needed.

No relevant conflicts of interest to declare.