Catalyzing the Critical Path Initiative: FDA's progress in drug development activities.

The US Food and Drug Administration (FDA) has directed considerable effort towards modernizing its regulatory processes over the past decade to address the challenges in the drug development sector. Through partnerships and input from stakeholders, multiple initiatives are under way, many projects have been launched, several have resulted in tangible results, and many are ongoing and under discussion. We are learning that collaborative efforts can better inform and leverage existing knowledge, that the challenges of data sharing and intellectual property can be overcome, and that there is wide interest in partnering to address key public health regulatory science issues.

A conformational constraint improves a beta-secretase inhibitor but for an unexpected reason.

During our ongoing efforts to develop a small molecule inhibitor targeting the beta-amyloid cleaving enzyme (BACE-1), we discovered a class of compounds bearing an aminoimidazole motif. Initial optimization led to potent compounds that have high Pgp efflux ratios. Crystal structure-aided design furnished conformationally constrained compounds that are both potent and have relatively low Pgp efflux ratios.

Identification of a small molecule beta-secretase inhibitor that binds without catalytic aspartate engagement.

A small molecule inhibitor of beta-secretase with a unique binding mode has been developed. Crystallographic determination of the enzyme-inhibitor complex shows the catalytic aspartate residues in the active site are not engaged in inhibitor binding. This unprecedented binding mode in the field of aspartyl protease inhibition is described.