As validated by actual patient data from a phase I study, the human PK of PF-03446962 were predicted within 1- to 2-fold of observations. NONMEM 7 was used to model monkey PK data and simulate human PK profiles based on the construct of a TMDD model using a population-based approach. Systems parameters as determined experimentally or obtained from the literature, such as binding affinity (k(on) and k(off)), internalization of the drug-target complex (k(int)), target degradation rate (k(deg)), and target abundance (R(0)), were directly integrated into the modeling and prediction. Because of the growing emphasis placed on popPK analyses by regulatory authorities, and the wealth of information that these analyses provide, it is more important than ever to consider how popPK fits into your own drug development program. Here, we present a model-based method for predicting the PK of PF-03446962, an IgG2 antibody directed against human ALK1 (activin receptor-like kinase 1) receptor. Population PK analyses are a crucial aspect of almost all drug development programs. This pastes your copied text into the NONMEM window. Then in the NONMEM window type the cd command as above and then right click once. PK prediction is especially challenging for monoclonal antibodies exhibiting nonlinear PK attributed to target-mediated drug disposition (TMDD). If you would rather copy and paste the pathway into NONMEM you can do so: Highlight the pathway to the folder in your explore window and copy it. In the drug discovery and development setting, the ability to accurately predict the human pharmacokinetics (PK) of a candidate compound from preclinical data is critical for informing the effective design of the first-in-human trial.