Population Pharmacokinetics (PopPK) Support for Pediatric Dosing of Biological Products

This study assesses the use of population pharmacokinetics (PopPK) in supporting pediatric dosing of novel biological drug products. The labeling for biologic drug products approved by the US Food and Drug Administration (FDA) from 2002 until 2021 was reviewed to identify those with a pediatric indication. For the drugs with a pediatric indication, the dosing regimen(s) based on age groups, dosing strategy, the use of PopPK to support the dose, and the types of pediatric clinical trials were reviewed. Data were collected from FDA's review documents and product labels on the Drugs@FDA website, and as needed, more clinical trial details were collected from PubMed and clinicaltrials.gov. The role of PopPK analyses in dosing was captured when mentioned in the label or review as playing a role in selecting the approved pediatric dose and/or in verifying the adequacy of the studied dose to support labeling. Between 2002 and 2021, FDA approved 169 biological products, and 78 of 169 (46%) products have an approved indication for which the label contains dosing recommendations for pediatric use. For the 78 products approved in pediatrics, there was a total of 180 clinical trials that included pediatric patients. Phase 3 pediatric trials commonly supported pediatric approval and dosing for the reviewed products (64%, 50/78 products; 56.1%, 101/180 trials). PopPK analyses were reported to play a critical role in dose selection, prediction, and verification for 40 of the 78 products (51%), including informing pediatric dosing in the absence of pediatric data (e.g., drugs approved under animal rule), comparing exposures to the exposure range observed in adults, and informing alternative dosing strategies in certain age or body weight groups. PopPK analyses have been applied in a variety of ways to inform pediatric dosing and support extrapolation from adult data or other pediatric age groups for biologics. Understanding and learning from these past cases on the use of pharmacometrics tools to support pediatric dosing of biological products can inform future pediatric development programs.