A Comparison of FDA and EMA Pregnancy and Lactation Labeling

Challenges of designing and conducting cohort studies and clinical trials in populations of pregnant people

Rheumatic and musculoskeletal diseases often affect individuals of childbearing age. The incidence and prevalence of rheumatic and musculoskeletal diseases is rising. More pregnancies in patients with rheumatic and musculoskeletal diseases are anticipated and some rheumatic and musculoskeletal diseases are associated with pregnancy complications (eg, miscarriages, fetal deaths, preterm births, and hypertensive disorders in pregnancy). Despite the need to understand the use of drugs to treat rheumatic and musculoskeletal diseases in pregnancy, clinical trials in pregnancy are rare, therapeutics in pregnancy are understudied, and pregnant individuals are routinely excluded as premarketing trial participants. Data on the effectiveness and safety of disease-modifying antirheumatic drugs are most often based on post-marketing observational data. Observational studies assessing the bidirectional relationship between rheumatic and musculoskeletal diseases and pregnancy, as well as interventional studies of treatments during pregnancy, are scarce. Historical reluctance to perform studies in what was deemed an at-risk group persists in pharmaceutical companies, regulatory bodies, and ethics boards. Additionally, patients must be engaged partners, which requires trust that the research respects the needs and interests of the patient and complies with the rules intended to protect the pregnant person and the fetus from harm. In this Series paper, we share challenges we have encountered in conducting prospective cohort studies and interventional trials of postmarketing approved medications, assessing pregnancy specific outcomes in pregnant women with rheumatic and musculoskeletal diseases in the EU, the UK, and the USA. We discuss the changing landscape around trials in pregnancy and present possible solutions to our challenges.

PBPK Modeling Approach to Predict the Behavior of Drugs Cleared by Metabolism in Pregnant Subjects and Fetuses

This study aimed to develop a physiologically based pharmacokinetic (PBPK) model that simulates metabolically cleared compounds' pharmacokinetics (PK) in pregnant subjects and fetuses. This model accounts for the differences in tissue sizes, blood flow rates, enzyme expression levels, plasma protein binding, and other physiological factors affecting the drugs' PK in both the pregnant woman and the fetus. The PBPKPlus™ module in GastroPlus® was used to model the PK of metoprolol, midazolam, and metronidazole for both non-pregnant and pregnant groups. For each of the three compounds, the model was first developed and validated against PK data in healthy non-pregnant volunteers and then applied to predict the PK in the pregnant groups. The model accurately described the PK in both the non-pregnant and pregnant groups and explained well the differences in the plasma concentration due to pregnancy. When available, the fetal plasma concentration, placenta, and fetal tissue concentrations were also predicted reasonably well at different stages of pregnancy. The work described the use of a PBPK approach for drug development and demonstrates the ability to predict differences in PK in pregnant subjects and fetal exposure for metabolically cleared compounds.