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.

Application of emerging biomarkers of acute kidney injury in development of kidney-sparing polypeptide-based antibiotics.

Polypeptide antibiotics, such as polymyxins and aminoglycosides, are essential for treatment of life-threatening Gram-negative infections. Acute kidney injury (AKI) attributed to treatment with these agents severely limits their clinical application. Because standard biomarkers (serum creatinine [sCRE] and blood urea nitrogen [BUN]) feature limited sensitivity, the development of novel biomarkers of AKI is important. Here, we compared the performance of standard and emerging biomarkers of AKI for the detection of nephrotoxicity caused by polymyxin B across multiple species (rat, dog and monkey). Further, we applied a biomarker-driven strategy for selection of new kidney-sparing polymyxin analogs. Polymyxin B treatment produced dose-dependent kidney injury observed as proximal tubular degeneration/regeneration and necrosis across all species. Dogs and monkeys had similar biomarker profiles that included increases of both standard (sCRE and BUN) and emerging (urinary neutrophil gelatinase-associated Lipocalin [NGAL] and urinary kidney injury molecule 1 [KIM-1]) biomarkers of AKI. In contrast, only urinary NGAL and urinary KIM-1 were sufficiently capable of detecting kidney injury in rats. Because rats provide a feasible model for screening compounds in drug development, we utilized urinary NGAL as a sensitive biomarker of AKI to screen and rank order compounds in a 2-day toxicity study. To our knowledge, this study provides a first example of successfully applying biomarkers of AKI in drug development.