Physiologically Based Pharmacokinetic Modeling in Pregnancy: A Systematic Review of Published Models

Physiologically based pharmacokinetic (PBPK) modeling and simulation in neonatal drug development: how clinicians can contribute

Introduction: Legal initiatives to stimulate neonatal drug development should be accompanied by development of valid research tools. Physiologically based (PB)-pharmacokinetic (PK) modeling and simulation are established tools, accepted by regulatory authorities. Consequently, PBPK holds promise to be a strong research tool to support neonatal drug development. Area covered: The currently available PBPK models still have poor predictive performance in neonates. Using an illustrative approach on distinct PK processes of absorption, distribution, metabolism, excretion, and real-world data in neonates, we provide evidence on the need to further refine available PBPK system parameters through generation and integration of new knowledge. This necessitates cross talk between clinicians and modelers to integrate knowledge (PK datasets, system knowledge, maturational physiology) or test and refine PBPK models. Expert opinion: Besides refining these models for 'small molecules', PBPK model development should also be more widely applied for therapeutic proteins and to determine exposure through breastfeeding. Researchers should also be aware that PBPK modeling in combination with clinical observations can also be used to elucidate age-related changes that are almost impossible to study based on in vivo or in vitro data. This approach has been explored for hepatic biliary excretion, renal tubular activity, and central nervous system exposure.

Antenatal sildenafil administration to prevent pulmonary hypertension in congenital diaphragmatic hernia (SToP-PH): study protocol for a phase I/IIb placenta transfer and safety study

Background

Congenital diaphragmatic hernia is an orphan disease with high neonatal mortality and significant morbidity. An important cause for this is pulmonary hypertension, for which no effective postnatal therapy is available to date. An innovative strategy aiming at treating or preventing pulmonary hypertension more effectively is urgently needed. Prenatal sildenafil administration to expectant mothers prevented fetal and neonatal vascular changes leading to pulmonary hypertension in several animal models, and is, therefore, a promising approach. Before transferring this antenatal medical approach to the clinic, more information is needed on transplacental transfer and safety of sildenafil in humans.

Methods

This is a randomized, investigator-blinded, double-armed, parallel-group, phase I/IIb study with as a primary objective to measure the in-vivo transplacental transfer of sildenafil in women in the second and early third trimester of pregnancy (sub-study 1; weeks: 20.0–32.6) and at term (sub-study 2; weeks: 36.6–40). Participants will be randomized to two different sildenafil doses: 25 or 75 mg. In sub-study 1, a single dose of the investigational product will be administered to women undergoing termination of pregnancy, and maternal and fetal blood samples will be collected for determination of sildenafil concentrations. In sub-study 2, sildenafil will be administered three times daily from 3 days before planned delivery until actual delivery, following which maternal and umbilical cord samples will be collected. Proxies of maternal and fetal tolerance as well as markers of fetal pulmonary vasodilation will also be measured.

Discussion

This is the first study evaluating in-vivo transplacental passage of sildenafil in humans.

Trial registration

EU Clinical Trials Register 2016–002619-17, validated on 12 August 2016.

Trial sponsor: UZ Leuven, Herestraat 49, 3000 Leuven.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2897-8) contains supplementary material, which is available to authorized users.