Exploration of cathepsin S inhibitors characterized by a triazole P1-P2 amide replacement.

This paper details exploration of a class of triazole-based cathepsin S inhibitors originally reported by Ellman and co-workers. SAR studies involving modifications across the whole inhibitor provide a perspective on the strengths and weaknesses of this class of inhibitors. In addition, we put the unique characteristics of this class of compounds into perspective with other classes of cathepsin S inhibitors.

1,4-Diazepane compounds as potent and selective CB2 agonists: optimization of metabolic stability.

A high-throughput screening campaign has identified 1,4-diazepane compounds which are potent Cannabinoid receptor 2 agonists with excellent selectivity against the Cannabinoid receptor 1. This class of compounds suffered from low metabolic stability. Following various strategies, compounds with a good stability in liver microsomes and rat PK profile have been identified.

Once-weekly liposomal amphotericin B as Candida prophylaxis in very low birth weight premature infants: a prospective, randomized, open-label, placebo-controlled pilot study.

OBJECTIVE: This study was conducted to evaluate once-weekly liposomal amphotericin B (L-AmB) for Candida prophylaxis in very low birth weight (VLBW) neonates. METHODS: This prospective, randomized, open-label, placebo-controlled study included neonates who were <32 weeks' gestational age, <7 days old, and weighing <1500 g at birth. Subjects were randomized to receive L-AmB 5 mg/kg per week or placebo (dextrose water) and were followed until 6 weeks of age. Surveillance cultures were obtained at baseline, at 72 hours, and weekly thereafter. Study drug was continued until 6 weeks after birth or the discontinuation of high-risk treatments and invasive devices, whichever occurred first. Blood cultures were obtained as clinically indicated. The primary end point was development of Candida colonization by 6 weeks' postnatal age; secondary end points included development of invasive candidiasis and occurrence of treatment-related adverse events. Safety variables included renal and hepatic function tests, incidence of grade III-IV intraventricular hemorrhage (IVH) and necrotizing enterocolitis (NEC), and mortality. RESULTS: Forty subjects were enrolled and randomized to receive L-AmB (12 males, 8 females; 50% white) or placebo (12 males, 8 females; 35% white). Subjects were evenly distributed by gestational age, age at enrollment, birth weight, race, and sex. Consent was withdrawn after completion of study treatment in 1 subject (L-AmB); 1 subject in each study arm died during the study; and 3 subjects were transferred back to their referring institutions (1 L-AmB, 2 placebo). Thus, 17 subjects in each arm completed all study procedures, although all 40 subjects were evaluable. Colonization before administration of study drug was noted in 4 L-AmB subjects (20%) and 1 placebo subject (5%); 1 (5%) and 3 (15%) subjects in the respective groups developed colonization while receiving study drug. No L-AmB subjects and 1 placebo subject developed candidiasis. One subject in each group died; these deaths were not considered related to study drug or fungal infection. There were no clinical differences between groups in the incidence of grade III-IV IVH, NEC, hypokalemia, nephrotoxicity, need for platelet or packed red blood cell transfusion, or mortality. CONCLUSIONS: L-AmB 5 mg/kg once weekly was generally well tolerated in these VLBW infants. The data did not allow evaluation of efficacy. A larger, multicenter, randomized clinical trial of L-AmB for Candida prophylaxis that is appropriately powered is warranted.

Microfluidic culture of single human embryonic stem cell colonies.

We have developed a miniaturized microfluidic culture system that allows experimentation on individual human embryonic stem cell (hESC) colonies in dynamic (flow applied) or static (without flow) conditions. The system consists of three inlet channels that converge into a cell-culture channel and provides the capability to spatially and temporally deliver specific treatments by using patterned laminar fluid flow to different parts of a single hESC colony. We show that microfluidic culture for 96 h with or without flow results in similar maintenance of hESC self-renewal, the capability to differentiate into three germ cell lineages, and to maintain a normal karyotype, as in standard culture dishes. Localized delivery of a fluorescent nucleic acid dye was achieved with laminar flow, producing staining only in nuclei of exposed cells. Likewise, cells in desired regions of colonies could be removed with enzymatic treatment and collected for analysis. Re-coating the enzyme treated area of the channel with extracellular matrix led to re-growth of hESC colonies into this region. Our study demonstrates the culture of hESCs in a microfluidic device that can deliver specific treatments to desired regions of a single colony. This miniaturized culture system allows in situ treatment and analysis with the ability to obtain cell samples from part of a colony without micromanipulation and to perform sensitive molecular analysis while permitting further growth of the hESC colony.

5-Aminomethylbenzimidazoles as potent ITK antagonists.

Benzamide 1 demonstrated good potency as a selective ITK inhibitor, however the amide moiety was found to be hydrolytically labile in vivo, resulting in low oral exposure and the generation of mutagenic aromatic amine metabolites. Replacing the benzamide with a benzylamine linker not only addressed the toxicity issue, but also improved the cellular and functional potency as well as the drug-like properties. SAR studies around the benzylamines and the identification of 10n and 10o as excellent tools for proof-of-concept studies are described.

Arylsulfonamide CB2 receptor agonists: SAR and optimization of CB2 selectivity.

A high-throughput screening campaign resulted in the discovery of a highly potent dual cannabinoid receptor 1 (CB1) and 2 (CB2) agonist. Following a thorough SAR exploration, a series of selective CB2 full agonists were identified.

Discovery of potent and selective PKC-theta inhibitors.

An uHTS campaign was performed to identify selective inhibitors of PKC-theta. Initial triaging of the hit set based on selectivity and historical analysis led to the identification of 2,4-diamino-5-nitropyrimidines as potent and selective PKC-theta inhibitors. A homology model and initial SAR is presented demonstrating that a 2-arylalkylamino substituent in conjunction with suitable 4-diamino substituent are essential for achieving selectivity over many kinases. Additional hit to lead profiling is presented on selected compounds.