Adrian Gill

Kinetic efficiency: the missing metric for enhancing compound quality?

The kinetics of ligand-target interactions have been recognised as being instrumental in dictating the efficacy of drug action. Increased focus on kinetic signatures in drug discovery has concincided with improvements in label free methodology for measuring kinetic parameters. Simultaneously, focus has also been applied to increasing the quality of compounds, in terms of their physicochemical properties. To facilitate this drive towards higher compound quality, metrics such as ligand efficiency and enthalpic efficiency have been employed. We propose another metric, kinetic efficiency, that may be used pragmatically to help identify those compounds displaying differentiated kinetic behaviour. The combination of these metrics has the potential to improve decision-making in drug discovery leading to higher quality compounds and series.

Stapled Vasoactive Intestinal Peptide (VIP) Derivatives Improve VPAC2 Agonism and Glucose-Dependent Insulin Secretion

Agonists of vasoactive intestinal peptide receptor 2 (VPAC2) stimulate glucose-dependent insulin secretion, making them attractive candidates for the treatment of hyperglycaemia and type-II diabetes. Vasoactive intestinal peptide (VIP) is an endogenous peptide hormone that potently agonizes VPAC2. However, VIP has a short serum half-life and poor pharmacokinetics in vivo and is susceptible to proteolytic degradation, making its development as a therapeutic agent challenging. Here, we investigated two peptide cyclization strategies, lactamisation and olefin-metathesis stapling, and their effects on VPAC2 agonism, peptide secondary structure, protease stability, and cell membrane permeability. VIP analogues showing significantly enhanced VPAC2 agonist potency, glucose-dependent insulin secretion activity, and increased helical content were discovered; however, neither cyclization strategy appeared to effect proteolytic stability or cell permeability of the resulting peptides.

Heart Regeneration: Opportunities and Challenges for Drug Discovery with Novel Chemical and Therapeutic Methods or Agents

Following a heart attack, more than a billion cardiac muscle cells (cardiomyocytes) can be killed, leading to heart failure and sudden death. Much research in this area is now focused on the regeneration of heart tissue through differentiation of stem cells, proliferation of existing cardiomyocytes and cardiac progenitor cells, and reprogramming of fibroblasts into cardiomyocytes. Different chemical modalities (i.e. methods or agents), ranging from small molecules and RNA approaches (including both microRNA and anti-microRNA) to modified peptides and proteins, are showing potential to meet this medical need. In this Review, we outline the recent advances in these areas and describe both the modality and progress, including novel screening strategies to identify hits, and the upcoming challenges and opportunities to develop these hits into pharmaceuticals, at which chemistry plays a key role.

What is the most important approach in current drug discovery: doing the right things or doing things right?

Doing the right things or doing things right: what is the most important focus for current drug discovery to secure delivery of new drugs of sustainable value to patients, healthcare professionals and healthcare providers? Some of the challenges faced today in drug discovery are addressed here: the relationship between R&D speed, cost and quality; how selection of performance metrics can affect the quality of the R&D output; the importance of leadership and management; how process orientation can affect, for example, creativity and innovation; the importance of selecting the right pharmacologic target and the right chemical lead; and why the use of drug-target kinetic and thermodynamic data to drive lead selection and lead optimization could increase success rates.

Optimisation of pharmacokinetic properties in a neutral series of 11β-HSD1 inhibitors

11β-HSD1 is increasingly seen as an attractive target for the treatment of type II diabetes and other elements of the metabolic syndrome. In this program of work we describe how a series of neutral 2-thioalkyl-pyridine 11β-HSD1 inhibitors were optimized in terms of their pharmacokinetic properties to give compounds with excellent bioavailability in both rat and dog through a core change to pyrimidine. A potential reactive metabolite issue with 4-thioalkyl-pyrimidines was circumvented by a switch from sulfur to carbon substitution.