Detailed explanation of the efficacy and role of Roprestim/Romigrastim

Romiplostim is a thrombopoietin peptide mimetic recently approved for the treatment of chronic immune thrombocytopenia (ITP) in adults. In randomized controlled studies, this drug has demonstrated an increase in platelet counts in most patients with ITP, including splenectomized and non-splenectomized patients. Its safety profile was favorable during up to 5 years of follow-up, suggesting that this may be a new treatment for ITP patients.

Roprostimis a recombinant platelet production-stimulatingFc-peptide fusion protein. The molecule has two domains: a peptide domain that binds to the TPO receptor and activates an intracellular pathway that stimulates megakaryopoiesis, and a crystallizable (Fc) fragment of the carrier antibody that undergoes endothelial recycling thereby extending its circulating half-life. Roplastin has no sequence homology with endogenous human, resulting in very low immunogenicity. Patients' responses to increased platelets vary, requiring individualized dosing. However, dose-dependent increases in platelet counts have been observed in clinical trials. Does not affect platelet destruction.

In vitro studies in human and murine megakaryocytes have shown that ropremilast binds to TPO receptors in a manner similar to endogenous TPO. In vivo studies using animals have shown that a single dose of loprostimin resulted in a dose-dependent increase in platelet counts on day 5, peaking between days 7 and 9. No subsequent thrombocytopenia was observed, and no neutralizing anti-TPO antibodies were detected. Roplastin has been shown to stimulate murine megakaryopoiesis and demonstrated a dose-dependent effect on megakaryocytic colony-forming units in murine bone marrow cultures.