Deciphering the In Vivo Performance of a Monoclonal Antibody to Neutralize Its Soluble Target at the Site of Action in a Mouse Collagen-Induced Arthritis Model.

PURPOSE: Study the disposition and target-neutralization capability of an anti-interleukin-6 (IL-6) monoclonal antibody (mAb) at the joint in a mouse collagen-induced arthritis (CIA) model. METHODS: A mechanistic pharmacokinetic/pharmacodynamic study was conducted in a mouse CIA model using CNTO 345, a rat anti-mouse IL-6 mAb, as model compound. The drug, total/free IL-6 concentrations in both serum and joint lavage fluid were quantitatively assessed and compared to those in the normal control mice. RESULTS: CNTO 345 exhibited higher clearance and significantly higher joint lavage/serum ratio in the CIA mice than in the normal control mice. The mAb concentrations in the joint lavage are approximately proportional to the serum concentrations at all the time points being examined. Dosing of CNTO 345 led to sustained free IL-6 suppression in both serum and joint lavage in a dose-dependent manner. A dose-dependent increase in total IL-6 was observed in serum, but not in the joint lavage fluid. Though no change in disease activity was observed following a single dose of anti-IL-6 mAb at peak of the disease, a dose-dependent decrease in serum amyloid A, a downstream biomarker of IL-6, was observed. CONCLUSIONS: This study provided quantitative assessments of the distribution and target-neutralization capability of an anti-IL-6 mAb at the site of action in an animal disease model.

A novel approach to evaluate the pharmacokinetic biocomparability of a monoclonal antibody derived from two different cell lines using simultaneous crossover design.

A parallel study design with a large number of subjects has been a typical path for pharmacokinetic (PK) biocomparability assessment of biotherapeutics with long half-lives and immunogenic propensity, for example, monoclonal antibodies (mAb). A recently published innovative bioanalytical method that can quantify mAb produced from two different cell lines in the same sample opened an avenue to exploring a simultaneous crossover study design for PK biocomparability assessment of biotherapeutics. Siltuximab, a chimeric IgG1 mAb-targeting interleukin-6, was studied as an example. The pharmacokinetic biocomparability of siltuximab derived from mouse myeloma (Sp2/0) cells and Chinese hamster ovary cells was previously assessed and demonstrated in a clinical PK biocomparability study that enrolled more than 140 healthy subjects using a parallel trial design. The biocomparability was successfully shown in six cynomolgus monkeys in a preclinical proof-of-concept study using the new crossover study design supported by the analytical method. The impact of antidrug antibodies on the assessment of biocomparability was minimal. This novel approach opened up a new arena for the evaluation of PK biocomparability of biotherapeutics with unique molecular signatures such as a mAb derived from different cell lines.

Normalization of skeletal muscle glycogen synthesis and glycolysis in rosiglitazone-treated Zucker fatty rats: an in vivo nuclear magnetic resonance study.

The aim of this study was to characterize insulin-stimulated skeletal muscle glucose metabolism in Zucker fatty rats and to provide insight into the therapeutic mechanism by which rosiglitazone increases insulin-stimulated glucose disposal in these rats. Metabolic parameters were measured using combined in vivo (13)C nuclear magnetic resonance (NMR) spectroscopy to measure skeletal muscle glucose uptake and its distributed fluxes (glycogen synthesis and glycolysis), and (31)P NMR was used to measure simultaneous changes in glucose-6-phosphate (G-6-P) during a euglycemic-hyperinsulinemic clamp in awake Zucker fatty rats. Three groups of Zucker fatty rats (fatty rosiglitazone [FRSG], fatty control [FC], lean control [LC]) were treated for 7 days before the experiment (3 mg/kg rosiglitazone or vehicle via oral gavage). Rates of glycolysis and glycogen synthesis were assessed after treatment by monitoring 1,6-(13)C(2) glucose label incorporation into 1-(13)C glycogen, 3-(13)C lactate, and 3-(13)C alanine during a euglycemic ( approximately 7-8 mmol/l)-hyperinsulinemic (10 mU. kg(-1). min(-1)) clamp. The FRSG group exhibited a significant increase in insulin sensitivity, reflected by an increased whole-body glucose disposal rate during the clamp (24.4 +/- 1.9 vs. 17.6 +/- 1.4 and 33.2 +/- 2.0 mg. kg(-1). min(-1) in FRSG vs. FC [P < 0.05] and LC [P < 0.01] groups, respectively). The increased insulin-stimulated glucose disposal in the FRSG group was associated with a normalization of the glycolytic flux (52.9 +/- 9.1) to LC (56.2 +/- 16.6) versus FC (18.8 +/- 8.6 nmol. g(-1). min(-1), P < 0.02) and glycogen synthesis flux (56.3 +/- 11.5) to LC (75.2 +/- 15.3) versus FC (16.6 +/- 12.8 nmol. g(-1). min(-1), P < 0.05). [G-6-P] increased in the FRSG and LC groups versus baseline during the clamp (13.0 +/- 11.1 and 16.9 +/- 5.8%, respectively), whereas [G-6-P] in the FC group decreased (-23.3 +/- 13.4%, P < 0.05). There were no differences between groups in intramyocellular glucose, as measured by biochemical assay. These data suggest that the increased insulin-stimulated glucose disposal in muscle after rosiglitazone treatment can be attributed to a normalization of glucose transport and metabolism.