CNTO 5825 is a human anti-interleukin-13 (IL-13) monoclonal antibody (mAb) that inhibits binding of human IL-13 to IL-13Ra1 and IL-13Ra2. The purpose of this investigation was to predict human pharmacokinetics (PK) of CNTO 5825 using different allometric approaches and non-clinical PK data in order to select the right and safe doses for first-in-human (FIH) study. After intravenous (IV) administration of CNTO 5825, clearance (CL) ranged from 9.98 to 11.49 ml/day/kg in rats and from 5.78 to 7.19 ml/day/kg in cynomolgus monkeys. The volume of distribution at steady-state (Vss) in rats was large (151.52-155.64 ml/kg) compared to cynomolgus monkey (49.77-61.10 ml/kg). The terminal half-life (T 1/2 ) ranged from 12.29 to 14.15 days in rats and from 6.61 to 7.73 days in cynomolgus monkeys. The PK of CNTO 5825 was linear in 1-10 mg/kg dose range in both species. The bioavailability after subcutaneous (SC) administration was 94% and 79% in rats and cynomolgus monkeys, respectively. The predicted CL and Vss based on allometric methods and PK data from rats and monkeys were within twofold of observed CL and Vss in human beings; the predicted CL and Vss in human beings (70 kg) based on time-invariant method with combined PK data from rats and monkeys were 4.84 AE 1.13 ml/day/kg and 68.93 AE 35.55 ml/kg, respectively. The selected doses for the FIH study based on time-invariant method and no observed adverse effect level in toxicity studies in rats and monkeys provided exposures that were subsequently shown to be well tolerated and safe in human beings.Several studies have shown that interleukin-13 (IL-13) in airways plays a central role in allergic asthma, where it regulates IgE production, eosinophilic inflammation, mucus secretion and airway hyper-responsivenes [1][2][3][4][5][6][7][8]. Interleukin-13 interacts with IL-13-positive cells in airway smooth muscles through a receptor complex consisting of IL-13 receptor alpha 1 (IL-13aR1) and interleukin-4 receptor alpha (IL-4Ra) subunits [4,5,8]. Therefore, neutralization of IL-13 represents a potential therapeutic approach for intervention in asthma [9,10].CNTO 5825 is a human anti-IL-13 monoclonal antibody (mAb) that potently and specifically inhibits binding of human IL-13 to both IL-13Ra1 and IL-13Ra2 [11]. Non-clinical studies have demonstrated that CNTO 5825 inhibited IL-13-mediated actions and supported advancing CNTO 5825 to first-in-human (FIH) study as a potential therapeutic agent for treatment of asthma.The importance of choosing the right and safe starting doses in FIH trials to mitigate risks of new molecular entities (NME) has been highlighted in guidelines from European Medicines Agency (EMA) and Food and Drug Administration (FDA) guidance on starting dose selection [12,13]. An approach that is widely applied for FIH starting dose selection involves allometrically scaling the no observed adverse effect level (NOAEL) obtained from toxicologically relevant species [12,13]. The pharmacokinetic/pharmacodynamic (PK/PD)-guided approach based on predicted...