Potent and Selective Human Prostaglandin F (FP) Receptor Antagonist (BAY-6672) for the Treatment of Idiopathic Pulmonary Fibrosis (IPF).

Idiopathic pulmonary fibrosis (IPF) is a rare and devastating chronic lung disease of unknown etiology. Despite the approved treatment options nintedanib and pirfenidone, the medical need for a safe and well-tolerated antifibrotic treatment of IPF remains high. The human prostaglandin F receptor (hFP-R) is widely expressed in the lung tissue and constitutes an attractive target for the treatment of fibrotic lung diseases. Herein, we present our research toward novel quinoline-based hFP-R antagonists, including synthesis and detailed structure-activity relationship (SAR). Starting from a high-throughput screening (HTS) hit of our corporate compound library, multiple parameter improvements-including increase of the relative oral bioavailability Frel from 3 to ≥100%-led to a highly potent and selective hFP-R antagonist with complete oral absorption from suspension. BAY-6672 (46) represents-to the best of our knowledge-the first reported FP-R antagonist to demonstrate in vivo efficacy in a preclinical animal model of lung fibrosis, thus paving the way for a new treatment option in IPF.

Quantitative Assessment of Drug Delivery to Tissues and Association with Phospholipidosis: A Case Study with Two Structurally Related Diamines in Development.

Drug induced phospholipidosis (PLD) may be observed in the preclinical phase of drug development and pose strategic questions. As lysosomes have a central role in pathogenesis of PLD, assessment of lysosomal concentrations is important for understanding the pharmacokinetic basis of PLD manifestation and forecast of potential clinical appearance. Herein we present a systematic approach to provide insight into tissue-specific PLD by evaluation of unbound intracellular and lysosomal (reflecting acidic organelles) concentrations of two structurally related diprotic amines, GRT1 and GRT2. Their intratissue distribution was assessed using brain and lung slice assays. GRT1 induced PLD both in vitro and in vivo. GRT1 showed a high intracellular accumulation that was more pronounced in the lung, but did not cause cerebral PLD due to its effective efflux at the blood-brain barrier. Compared to GRT1, GRT2 revealed higher interstitial fluid concentrations in lung and brain, but more than 30-fold lower lysosomal trapping capacity. No signs of PLD were seen with GRT2. The different profile of GRT2 relative to GRT1 is due to a structural change resulting in a reduced basicity of one amino group. Hence, by distinct chemical modifications, undesired lysosomal trapping can be separated from desired drug delivery into different organs. In summary, assessment of intracellular unbound concentrations was instrumental in delineating the intercompound and intertissue differences in PLD induction in vivo and could be applied for identification of potential lysosomotropic compounds in drug development.