The discovery and characterization of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor potentiator N-{(3S,4S)-4-[4-(5-cyano-2-thienyl)phenoxy]tetrahydrofuran-3-yl}propane-2-sulfonamide (PF-04958242).

A unique tetrahydrofuran ether class of highly potent α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor potentiators has been identified using rational and structure-based drug design. An acyclic lead compound, containing an ether-linked isopropylsulfonamide and biphenyl group, was pharmacologically augmented by converting it to a conformationally constrained tetrahydrofuran to improve key interactions with the human GluA2 ligand-binding domain. Subsequent replacement of the distal phenyl motif with 2-cyanothiophene to enhance its potency, selectivity, and metabolic stability afforded N-{(3S,4S)-4-[4-(5-cyano-2-thienyl)phenoxy]tetrahydrofuran-3-yl}propane-2-sulfonamide (PF-04958242, 3), whose preclinical characterization suggests an adequate therapeutic index, aided by low projected human oral pharmacokinetic variability, for clinical studies exploring its ability to attenuate cognitive deficits in patients with schizophrenia.

Quantitative pharmacokinetic/pharmacodynamic analyses suggest that the 129/SVE mouse is a suitable preclinical pharmacology model for identifying small-molecule γ-secretase inhibitors.

Alzheimer's disease (AD) poses a serious public health threat to the United States. Disease-modifying drugs slowing AD progression are in urgent need, but they are still unavailable. According to the amyloid cascade hypothesis, inhibition of ß- or γ-secretase, key enzymes for the production of amyloid ß (Aß), may be viable mechanisms for the treatment of AD. For the discovery of γ-secretase inhibitors (GSIs), the APP-overexpressing Tg2576 mouse has been the preclinical model of choice, in part because of the ease of detection of Aß species in its brain, plasma, and cerebrospinal fluid (CSF). Some biological observations and practical considerations, however, argue against the use of the Tg2576 mouse. We reasoned that an animal model would be suitable for GSI discovery if the pharmacokinetic (PK)/pharmacodynamic (PD) relationship of a compound for Aß lowering in this model is predictive of that in human. In this study, we assessed whether the background 129/SVE strain is a suitable preclinical pharmacology model for identifying new GSIs by evaluating the translatability of the intrinsic PK/PD relationships for brain and CSF Aß across the Tg2576 and 129/SVE mouse and human. Using semimechanistically based PK/PD modeling, our analyses indicated that the intrinsic PK/PD relationship for brain Aßx-42 and CSF Aßx-40 in the 129/SVE mouse is indicative of that for human CSF Aß. This result, in conjunction with practical considerations, strongly suggests that the 129/SVE mouse is a suitable model for GSI discovery. Concurrently, the necessity and utilities of PK/PD modeling for rational interpretation of Aß data are established.