Immunogenicity and toxicokinetics assessment of the mono-PEGylated recombinant human interleukin-11 in cynomolgus monkeys.

AIM: Protein therapeutics have potential to elicit immune responses resulting in undesirable anti-drug antibodies (ADA) that might affect product efficacy and patient safety, and should be assessed in animals before applying the treatment to humans. In this paper, we aim to assess the immunogenicity and toxicokinetics of the mono-PEGylated recombinant human interleukin-11 (rhIL-11), a novel protein therapeutic for the treatment of chemotherapy-induced thrombocytopenia, in repeated administration to cynomolgus monkeys. MAIN METHODS: Enzyme-linked immunosorbent assay (ELISA) methods were developed to measure ADA responses and plasma PEGylated IL-11 (PEG-IL11) concentration in monkeys. Assay parameters of immunogenicity and toxicokinetics methods were evaluated during validation in accordance with regulatory guidelines. We also employed cell-based assays to test the neutralizing activity of ADA provoked in monkeys. KEY FINDINGS: The results showed that weak immunogenicity occurred in some monkeys after receiving repeated dose of 0.1-0.3 mg/kg by subcutaneous administration and disappeared after the recovery period. More pronounced immunogenicity occurred at high dose of 0.9 mg/kg, with a higher positive rate and titer, and some ADAs had neutralizing activity, but it can be greatly reduced after recovery. Such ADAs generated in monkeys may be accounted for the plasma toxicokinetics changes of PEG-IL11 and a minor reduction in systemic exposure. SIGNIFICANCE: These methods have been successfully applied to immunogenicity and toxicokinetic studies of PEG-IL11 in repeated dose toxicity following subcutaneous administration to monkeys, and could be successfully used in clinical trials after some modifications.

Development and validation of a LC-MS/MS method for quantification of hetrombopag for pharmacokinetics study.

Hetrombopag as the derivative of ethylidene hydrazine carboxamide was recently developed into a novel patented non-peptide thrombopoietin mimetic and thrombopoietin receptor agonist to treat idiopathic thrombocytopenic purpura. To study the pharmacokinetics of hetrombopag, a highly sensitive, rapid and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for determination of hetrombopag in rat plasma. After protein precipitation extraction, the chromatography separation of analyte and internal standard named eltrombopag as an marketed analog of hetrombopag was performed on an Synergi Polar-RP column at the flow rate of 0.5 mL/min, and the determination was conducted on an API4000 triple quadrupole mass spectrometry in the multiple reaction monitoring mode using the respective [M+H](+) ions m/z 459.2 â†’ 200.9 for hetrombopag and m/z 443.2 â†’ 229.0 for IS. The lower limit of quantification was established to be 1 ng/mL, and the linear scope of standard curve was 1-1000 ng/mL. Both the precision (RSD%) and accuracy (RE%) were within the acceptable criterion of below 15 %. The validated method was successfully applied to quantify hetrombopag in the rat plasma and investigate the pharmacokinetics.