Case study of remission in adults with immune thrombocytopenia following cessation of treatment with the thrombopoietin mimetic romiplostim

Objectives: In adults, immune thrombocytopenia (ITP), characterized by platelet counts < 100 x 10(9)/l, is typically chronic, with remission reported infrequently >= 3 years post-diagnosis. The thrombopoietin mimetic romiplostim increases platelet counts and reduces use of concomitant ITP medications in chronic ITP. While often perceived as a long-term treatment, dose-adjustment rules allow romiplostim to be discontinued when hemostatic platelet counts are reached, as reported in Amgen trials. Methods: Eight romiplostim trials were examined for remission, defined as >= 26 consecutive weeks of platelets >= 50 x 10(9)/l without treatment. Results: Remission was identified in 27 patients; median (quartile 1 [Q1], quartile 3 [Q3]) ITP duration of 2.1 (0.5, 4.2) years, 17/ 27 (63%) having ITP for > 1 year, mean baseline platelets 20.9 x 10(9)/l, median preremission maximum dose 3.0 mu g/kg, 12/27 (44%) were splenectomized at baseline, and there were 40-276 cumulative weeks of romiplostim with median time to remission 7.1 months. Discussion/Conclusion: No clear-cut predictors of remission were apparent; however, a number of patients had ITP for < 1 year and received romiplostim for < 1 year.