Investigations of Long-Acting Formulations in Children, Adolescents, and Pregnant Women: A Systematic Review

Background/Objectives: Long-acting and extended-release drug delivery strategies have greatly improved treatment for a variety of medical conditions. Special populations, specifically infants, children, young people, and pregnant and postpartum women, could greatly benefit from access to these strategies but are often excluded from clinical trials. We conducted a systematic review of all clinical studies involving the use of a long-acting intramuscular injection or implant in infants, children, young people, and pregnant and postpartum people. Methods: Pubmed, Embase, and Cochrane Library trials were searched. Studies published from 1980 through 2018 were included. After abstract review and duplication removal, full-text articles were obtained for further review, reviewed by two independent reviewers, and disagreements were resolved by a third reviewer. Results: a total of 101 studies of long-acting therapeutics were completed in these populations, and most (80%) of these had a sample size of <100 individuals. Therapeutics for only a small pool of indications were examined in these studies, with 72% of the studies investigating hormonal contraception or other types of hormonal treatments. Only 9.3% of the studies in children and 16.7% of the studies in pregnant people collected any pharmacokinetic (PK) data. Conclusions: Long-acting formulations may behave differently (both pharmacokinetically and pharmacodynamically) in childhood, adolescence, and pregnancy as compared to non-pregnant adulthood. Therefore, it is imperative to increase and improve upon the studies investigating long-acting formulations in order to close the knowledge gap and improve care and treatment in these special populations.