Arylsulfonamide pyrimidines as VLA-4 antagonists.

A series of (S)-2-(2-(diethylamino)-5-(N-alkyl-N-sulfonamido)pyrimidin-4-ylamino)-3-(4-(carbamoyloxy)phenyl)propanoic acid is discovered as orally available VLA-4 antagonists. Representative compounds 11b and 11p showed efficacy in multiple in vivo animal models. The in vitro selectivity of 11p is also described.

PEG conjugates of potent α4 integrin inhibitors, maintaining sustained levels and bioactivity in vivo, following subcutaneous administration.

Mitsunobu reactions were employed to link t-butyl esters of α4 integrin inhibitors at each of the termini of a three-arm, 40 kDa, branched PEG. Cleavage of the t-butyl esters using HCO2H provided easily isolated PEG derivatives, which are potent α4 integrin inhibitors, and which achieve sustained levels and bioactivity in vivo, following subcutaneous administration to rats.

Orally available and efficacious α4ß1/α4ß7 integrin inhibitors.

A series of potent α4ß1/α4ß7 integrin inhibitors is reported, including an inhibitor 12d with remarkable oral exposure and efficacy in rat models of rheumatoid arthritis and Crohn's disease.

Discovery of a potent, orally bioavailable pyrimidine VLA-4 antagonist effective in a sheep asthma model.

A series of N-(pyrimidin-4-yl)-phenylalanine VLA-4 antagonists is described. Optimization of substituents at the 2 and 5 positions of the pyrimidine ring gave 14, a very potent VLA-4 inhibitor which is orally active in a sheep asthma model.

Discovery of sulfonamide-pyrazole gamma-secretase inhibitors.

Utilizing a pharmacophore hypothesis, previously described gamma-secretase inhibiting HTS hits were evolved into novel tricyclic sulfonamide-pyrazoles, with high in vitro potency, good brain penetration, low metabolic stability, and high clearance.

Amyloid precursor protein selective gamma-secretase inhibitors for treatment of Alzheimer's disease.

INTRODUCTION: Inhibition of gamma-secretase presents a direct target for lowering Aß production in the brain as a therapy for Alzheimer's disease (AD). However, gamma-secretase is known to process multiple substrates in addition to amyloid precursor protein (APP), most notably Notch, which has limited clinical development of inhibitors targeting this enzyme. It has been postulated that APP substrate selective inhibitors of gamma-secretase would be preferable to non-selective inhibitors from a safety perspective for AD therapy. METHODS: In vitro assays monitoring inhibitor potencies at APP γ-site cleavage (equivalent to Aß40), and Notch ε-site cleavage, in conjunction with a single cell assay to simultaneously monitor selectivity for inhibition of Aß production vs. Notch signaling were developed to discover APP selective gamma-secretase inhibitors. In vivo efficacy for acute reduction of brain Aß was determined in the PDAPP transgene model of AD, as well as in wild-type FVB strain mice. In vivo selectivity was determined following seven days x twice per day (b.i.d.) treatment with 15 mg/kg/dose to 1,000 mg/kg/dose ELN475516, and monitoring brain Aß reduction vs. Notch signaling endpoints in periphery. RESULTS: The APP selective gamma-secretase inhibitors ELN318463 and ELN475516 reported here behave as classic gamma-secretase inhibitors, demonstrate 75- to 120-fold selectivity for inhibiting Aß production compared with Notch signaling in cells, and displace an active site directed inhibitor at very high concentrations only in the presence of substrate. ELN318463 demonstrated discordant efficacy for reduction of brain Aß in the PDAPP compared with wild-type FVB, not observed with ELN475516. Improved in vivo safety of ELN475516 was demonstrated in the 7d repeat dose study in wild-type mice, where a 33% reduction of brain Aß was observed in mice terminated three hours post last dose at the lowest dose of inhibitor tested. No overt in-life or post-mortem indications of systemic toxicity, nor RNA and histological end-points indicative of toxicity attributable to inhibition of Notch signaling were observed at any dose tested. CONCLUSIONS: The discordant in vivo activity of ELN318463 suggests that the potency of gamma-secretase inhibitors in AD transgenic mice should be corroborated in wild-type mice. The discovery of ELN475516 demonstrates that it is possible to develop APP selective gamma-secretase inhibitors with potential for treatment for AD.

Synthesis, characterization and evaluation of pro-drugs of VLA-4 antagonists.

A pro-drug strategy to identify orally efficacious VLA-4 antagonists is described. Potential pro-drugs were evaluated for their physical chemical characteristics and in vitro properties, including solubility, stability, permeability and plasma stability. Based on this characterization, promising compounds were identified for in vivo pharmacokinetic evaluation. These studies resulted in the identification of a pro-drug that exhibited desirable blood levels in PK studies in several different species.