Application of blood microsampling in cynomolgus monkey and demonstration of equivalent monoclonal antibody PK parameters compared to conventional sampling

PURPOSE

The purpose of this study was to evaluate the suitability of whole blood microsampling procedures in non-human primate (NHP) to support toxicokinetic assessments of biotherapeutics in non-human primates.

METHOD

A one-month single dose intravenous pharmacokinetic (PK) study was performed in male cynomolgus monkeys with a human IgG1 control monoclonal antibody (mAb) as a surrogate monoclonal antibody biotherapeutic. In this study, both serum samples (conventional sample collection) and microsampling samples were collected. Microsampling samples were collected from two sites on cynomolgus monkey, with each site using two different devices for the whole blood collection. The drug concentrations from all sample types were determined using a quantitative ligand binding assay (LBA). The PK parameters obtained from microsampling samples and serum samples were examined using a standard PK analysis method. The comparability of key PK parameters from both sample types were analyzed statistically.

RESULTS

Similar profiles of drug concentrations versus timepoints from all sampling procedures were observed. The correlations of PK concentration data obtained from serum and microsampling samples were ≥ 0.97 using Brand Alman Plot analysis. The key PK parameters obtained from microsampling samples were comparable to those obtained from serum samples (the % differences of mean PK parameters obtained from both sample types were within ±25%).

CONCLUSION

This study confirmed that PK parameters obtained from samples using microsampling were comparable to that of serum samples in cynomolgus monkeys. Therefore, the microsampling procedure described can be used as a substitute for conventional sampling procedure to support PK/TK studies of biotherapeutics in non-clinical product developments.

Induction and Impact of Anti-Drug Responses Elicited by a Human Recombinant Coagulation Factor FXaI16L in Preclinical Species

This paper presents a systemic investigation of ADA development and ADA impact of a human coagulation factor in nonclinical species during drug development and provides insights into potential implications in human if a similar ADA occurs. FXa^I16L-induced ADA response was characterized in monkey, mouse, rat, and dog in different studies, and ADA effects on pharmacokinetic and/or pharmacodynamics of FXa^I16L were further examined in ADA-negative and ADA-positive animals. After repeated administrations, FXa^I16L elicited a dose and exposure day-dependent ADA response which ranged from no response to a transient or persistent response. Increase in exposure day and increase in dose generally enhanced ADA incidence except for a decrease in ADA incidence was observed in monkeys after repeated high-dose administrations. The observable ADA impact on pharmacokinetics was only found in some ADA+ animals and included decrease in clearance and increase in systemic exposure but no increase in half-life. In addition, no or limited effect on pharmacodynamics by ADA was observed. The earliest ADA response was observed after three exposure days, marked elevation of drug exposure was observed in some animals at log titer > 2.0, and the highest antibody titer excited was about 4 (Log10) in all species. A correlation between ADA induction and accumulative exposure after various repeat treatments in different species was found for FXa^I16L. In addition, potential immunogenicity risk and mitigation of ADA in clinics are discussed.

Preclinical Pharmacokinetics, Pharmacodynamics, Tissue Distribution, and Interspecies Scaling of Recombinant Human Coagulation Factor XaI16L

FXa^I16L is a recombinant human FXa variant which is currently being evaluated in the clinic for treating intracerebral hemorrhage. The aim of our studies is to investigate overall pharmacokinetics, pharmacodynamics, and distribution of FXa^I16L in preclinical species, and to understand its potential implication in human. Pharmacokinetics of FXa^I16L was examined using active site probes and the results showed that FXa^I16L displayed fast clearance, low volume of distribution, and a very short plasma resident time in mice, rats, and monkeys. When pharmacodynamics was examined in monkeys, concentration effects of FXa^I16L on shortening of active partial prothrombin time and formation of thrombin-antithrombin complex were observed. Furthermore, biodistribution study was conducted in mice using radiolabeled FXa^I16L, and showed that ¹²⁵I-FXa^I16L has high plasma protein binding and significant liver and kidney distribution. Human pharmacokinetic prediction for first-in-human dosing was evaluated using allometric scaling, liver blood flow, and a fixed coefficient method, and single species allometric scaling using monkey data was most predictive for human pharmacokinetics of FXa^I16L.