Report on characterisation In vitro human/animal mammary epithelial cell culture models, including comparison between in vitro models

Task 3.2: Development of an improved in vitro model to identify parameters determining the rate and extent of blood-milk excretion (M4-M48) (KUL, NVS, UNIBO, Bionotus, Covance). The aim is to develop and characterise an improved in vitro model for drug passage from maternal blood to human breast milk. The model will be based on cultured human mammary epithelial cells11,12. In parallel, a mammary epithelial cell model corresponding to the species selected for Task 3.3 will be established. Primary cultures of mammary epithelial cells, grown as monolayers or on inserts, will be utilised to determine transfer rate data for the model drugs across mammary epithelial cells13. The literature search performed in Task 3.1 will be used to inform the development of the in vitro models. At least 10 model compounds selected in Task 3.1 will be used in a first wave of in vitro experiments. High-throughput and sensitive LC-MSMS methods will be developed and validated according to EMA/FDA guidelines and EBF recommendations. These methods will be applied for accurate and precise measurement of drugs in in vitro samples. As a secondary objective, the data obtained in Task 3.2 will be compared to data generated on existing models of trans-epithelial transport (e.g., Caco-2 / MDCK / PAMPA) to investigate whether those existing models could predict the mammary cell culture data and could be used as replacement. This would allow utilisation of a large amount of existing data from easy-to-access assays that are commonly found in discovery programs across industry.