Adventures in drug discovery: potent agents based on ligands for cell-surface receptors.

How does one go about discovering new drugs? This question is addressed by descriptions of drug discovery research in three project areas that pertain to antagonist ligands for cell-surface receptors. The molecular targets of interest are protease-activated receptor-1 (PAR-1), vasopressin receptors (V1a and V2 subtypes), and the fibrinogen receptor (GPIIb/IIIa). I present different approaches to the identification of high-affinity ligands for these receptors, en route to drug candidates. The PAR-1 project resulted in a pharmacological tool compound that facilitated in vivo proof-of-principle studies, whereas the vasopressin and fibrinogen receptor projects resulted in several preclinical development compounds, three of which advanced into human clinical trials.