Multicentre, randomised phaseIIIstudy of the efficacy and safety of eltrombopag in Chinese patients with chronic immune thrombocytopenia

Eltrombopag, a thrombopoietin receptor agonist, raises platelet counts and reduces bleeding in patients with immune thrombocytopenia (ITP). In Chinese patients, eltrombopag was evaluated at an initial dose of 25 mg, vs. 50 mg for non-Asians, because the plasma exposure of eltrombopag is higher in East Asians. A multicentre, double-blind, randomised, placebo-controlled, 8-week, phase III study enrolled 155 patients with chronic, previously treated ITP. Dosage could be adjusted (25-75 mg/day) to maintain platelet counts 50-250 × 10⁹ /l. The primary efficacy endpoint was the proportion of patients with a platelet count ≥50 × 10⁹ /l after Day 42. Pharmacokinetics and pharmacodynamics of eltrombopag were analysed in an open-label extension. After Day 42, 57·7% of eltrombopag-treated and 6·0% of placebo-treated patients achieved platelet counts ≥50 × 10⁹ /l. Odds of achieving a platelet count ≥50 × 10⁹ /l were 26·08 times greater with eltrombopag than placebo (P < 0·001). Compared with placebo, time to response and duration of response were better with eltrombopag (P < 0·001) and the odds of any bleeding were reduced by 72% (P = 0·001). Tolerability, pharmacokinetics, and pharmacokinetics/pharmacodynamics were similar to previous findings in East Asian patients. In conclusion, in Chinese patients with chronic ITP, eltrombopag 25 mg once daily, elevated platelet counts to a safe range and reduced bleeding.