Romiplostim (Nplate®, Amgen Inc.) is an orphan drug approved for the treatment of chronic refractory immune thrombolytic purpura (ITP) in adult and pediatric patients. Limited availability of pharmacokinetic (PK) data and large inter- and intra-subject variability in PK and platelet response is a challenge in the clinical development of a romiplostim biosimilar. We compared pharmacokinetics (PK), pharmacodynamics (PD)/efficacy, and safety of a romiplostim biosimilar with Nplate in 24 patients with ITP following a single 3 μg/kg dose, and assessed efficacy of the romiplostim biosimilar at a titrated dose range of 1–5 μg/kg in 50 patients with ITP. The PK of the romiplostim biosimilar did not differ compared to the PK of Nplate, and PD/efficacy responses were similar between the products following the single dose. The romiplostim biosimilar showed historically comparable PD/efficacy with Nplate over 8 weeks when treated at the titrated dose range. It was well tolerated in both the studies.

Romiplostim（Nplate®，Amgen Inc.）是一种孤儿药，已获批用于治疗成人和儿童患者的慢性难治性免疫性溶栓性紫癜 (ITP)。药代动力学 (PK) 数据的有限可用性以及 PK 和血小板反应的较大的受试者间和受试者内变异性是 romiplostim 生物仿制药临床开发中的一个挑战。我们在 24 名 ITP 患者中比较了 romiplostim 生物仿制药与 Nplate 单次 3 μg/kg 剂量后的药代动力学 (PK)、药效学 (PD)/疗效和安全性，并评估了 romiplostim 生物仿制药在滴定剂量范围为 1 的疗效–5 μg/kg，50 名 ITP 患者。romiplostim 生物仿制药的 PK 与 Nplate 的 PK 相比没有差异，单剂量后产品的 PD /疗效反应相似。当在滴定剂量范围内治疗时，romiplostim 生物仿制药在 8 周内显示出与 Nplate 具有历史可比性的 PD/疗效。在这两项研究中，它的耐受性都很好。