Effectiveness and safety of romiplostim among patients with newly diagnosed, persistent and chronic ITP in routine clinical practice in central and Eastern Europe: an analysis of the PLATON study.

Objectives: The objective of this analysis was to assess the effectiveness and safety of romiplostim in the real-world by duration of primary immune thrombocytopenia (ITP): <3 ('newly diagnosed'), 3-12 ('persistent'), and >12 ('chronic') months.

Methods: This was a post-hoc analysis of the PLATON single-arm, observational cohort study of adults from five Central and Eastern European countries receiving ≥1 romiplostim dose as second-line therapy, or where surgery was contraindicated. Durable (≥75% of measurements with ≥50 × 10 platelets/L during weeks 14-24) and overall platelet response (≥30 or ≥50 × 10 platelets/L at least once), rescue therapy, bleeding, discontinuation of other ITP medications, and adverse drug reactions (ADRs) were assessed.

Results: Of 100 participants, 22.0% had newly diagnosed, 17.0% had persistent, and 61.0% had chronic ITP. Prior splenectomy was most frequently reported in chronic ITP (32.8%), prior bleeding was predominant in newly diagnosed patients (68.2%). Durable platelet response was achieved in 50.0% (95% confidence interval [CI]: 28.2-71.8%) of newly diagnosed, 35.3% (95% CI: 14.2-61.7%) of persistent, and 31.1% (95% CI: 19.9-44.3%) of chronic ITP patients. Overall platelet response was achieved in >80% across all strata. Safety was comparable across groups, with a low incidence of thrombotic ADRs and no bone marrow ADRs.

Discussion: In this real-world study, platelet response to romiplostim was consistent across all strata of ITP duration. ADRs were infrequent and similar across ITP settings.

Conclusion: These findings support the utilization of romiplostim in patients with newly diagnosed and persistent ITP in accordance with recent guidelines and the recent romiplostim label extension.