Wesley Peter Blackaby

Identification of an Orally Bioavailable, Potent, and Selective Inhibitor of GlyT1.

Amalgamation of the structure-activity relationship of two series of GlyT1 inhibitors developed at Merck led to the discovery of a clinical candidate, compound 16 (DCCCyB), which demonstrated excellent in vivo occupancy of GlyT1 transporters in rhesus monkey as determined by displacement of a PET tracer ligand.

Optimisation of a series of potent, selective and orally bioavailable GlyT1 inhibitors.

A series of heterocyclic sulfonamides have been developed which are potent and selective inhibitors of hGlyT1. SAR studies to optimise the in vitro and in vivo properties are described. Optimisation of the central scaffold resulted in cyclohexane sulfones 28 and 29, which have good PK properties and show promise for further development.

Probing Mechanisms of CYP3A Time-Dependent Inhibition Using a Truncated Model System

Time-dependent inhibition (TDI) of cytochrome P450 (CYP) enzymes may incur serious undesirable drug-drug interactions and in rare cases drug-induced idiosyncratic toxicity. The reactive metabolites are often generated through multiple sequential biotransformations and form adducts with CYP enzymes to inactivate their function. The complexity of these processes makes addressing TDI liability very challenging. Strategies to mitigate TDI are therefore highly valuable in discovering safe therapies to benefit patients. In this Letter, we disclose our simplified approach toward addressing CYP3A TDI liabilities, guided by metabolic mechanism hypotheses. By adding a methyl group onto the α carbon of a basic amine, TDI activities of both the truncated and full molecules (7a and 11) were completely eliminated. We propose that truncated molecules, albeit with caveats, may be used as surrogates for full molecules to investigate TDI.