1 This manuscript presents the preclinical profile of lumiracoxib, a novel cyclooxygenase-2 (COX-2) selective inhibitor. 2 Lumiracoxib inhibited purified COX-1 and COX-2 with K i values of 3 and 0.06 mM, respectively. In cellular assays, lumiracoxib had an IC 50 of 0.14 mM in COX-2-expressing dermal fibroblasts, but caused no inhibition of COX-1 at concentrations up to 30 mM (HEK 293 cells transfected with human COX-1). 3 In a human whole blood assay, IC 50 values for lumiracoxib were 0.13 mM for COX-2 and 67 mM for COX-1 (COX-1/COX-2 selectivity ratio 515). 4 Lumiracoxib was rapidly absorbed following oral administration in rats with peak plasma levels being reached between 0.5 and 1 h. 5 Ex vivo, lumiracoxib inhibited COX-1-derived thromboxane B 2 (TxB 2 ) generation with an ID 50 of 33 mg kg À1, whereas COX-2-derived production of prostaglandin E 2 (PGE 2 ) in the lipopolysaccharidestimulated rat air pouch was inhibited with an ID 50 value of 0.24 mg kg À1 . 6 Efficacy of lumiracoxib in rat models of hyperalgesia, oedema, pyresis and arthritis was dosedependent and similar to diclofenac. However, consistent with its low COX-1 inhibitory activity, lumiracoxib at a dose of 100 mg kg À1 orally caused no ulcers and was significantly less ulcerogenic than diclofenac (Po0.05). 7 Lumiracoxib is a highly selective COX-2 inhibitor with anti-inflammatory, analgesic and antipyretic activities comparable with diclofenac, the reference NSAID, but with much improved gastrointestinal safety. British Journal of Pharmacology (2005) 144, 538-550. doi:10.1038/sj.bjp.0706078 Published online 17 January 2005 Keywords: Lumiracoxib; COX-2; cyclooxygenase-2 selective inhibitor; preclinical Abbreviations: AUC, area-under-curve of the concentration vs time curve; C max , maximum drug plasma concentration; CFA, complete Freund's adjuvant; 51 Cr-EDTA, chromium-51 labelled EDTA; COX, cyclooxygenase; D 30 , dose at which 30% inhibition was achieved; DMSO, dimethyl sulphoxide; F 0 , fraction of uninhibited enzyme at equilibrium; GI, gastrointestinal; HEK, human embryonic kidney; IL-1, interleukin-1; K i , inhibitor constant; k on , second-order rate constant representing speed at which an inhibitor binds to an enzyme; I, inhibitor concentration; LC/MS/MS, liquid chromatography/mass spectrometry/mass spectrometry; LPS, lipopolysaccharide; NSAID, nonsteroidal anti-inflammatory drug; O 2 , oxygen; PGE 2 , prostaglandin E 2 ; s, arachidonic acid concentration; t 1/2 , half-life; t opt , time to optimal velocity; TxB 2 , thromboxane B 2 ; V 0 , velocity in the absence of inhibitor; V obs , observed velocity in the presence of inhibitor; V opt , highest observed O 2 consumption velocity; V max , Michaelis-Menten constant for the maximal calculated velocity

Novel indeno[1,2-c]isoquinolinone derivatives were synthesized and evaluated as inhibitors of the nuclear enzyme poly(ADP-ribose) polymerase-1 (PARP-1). These potent nonmutagenic PARP-1 inhibitors possess an additional five-membered ring between the B and C rings of 6(5H)-phenanthridinone. The most potent PARP-1 inhibitors were obtained from the substitution of the D ring at the C-9 position, in particular sulfonamide and N-acyl analogues (6 and 11). The 9-sulfonamide analogues 11a and 12a exhibited IC(50) values of 1 and 10 nM, respectively.

ELX‐02 is an investigational synthetic eukaryotic ribosome–selective glycoside optimized as a translational read‐through molecule that induces read through of nonsense mutations, resulting in normally localized full‐length functional proteins. ELX‐02 is being developed as a therapy for genetic diseases caused by nonsense mutations. Two phase 1a, randomized, double‐blind placebo‐controlled, single‐ascending‐dose studies were conducted in healthy human subjects to evaluate the safety and pharmacokinetics of ELX‐02. Single subcutaneously injected doses of ELX‐02 between 0.3 mg/kg and 7.5 mg/kg showed an acceptable safety profile without severe or serious drug‐related adverse events, including a lack of renal and ototoxicity events. Injection of ELX‐02 resulted in a rapid time to peak concentration and elimination phase, with complete elimination from the vascular compartment within 10 hours. ELX‐02 area under the concentration‐time curve to infinity showed dose‐exposure linearity (24‐fold increase for a 25‐fold dose increase), and the maximum concentration showed dose proportionality (17‐fold increase for a 25‐fold increase). The mean apparent volume of distribution was dose dependent, suggesting an increased distribution and tissue uptake of ELX‐02 at higher doses. The primary route of excretion was in the urine, with the majority of the compound excreted unchanged. These results support the evaluation of the safety, pharmacokinetics, and efficacy of repeat dosing in future studies.

We describe novel rifamycin derivatives (new chemical entities [NCEs]) that retain significant activity against a comprehensive collection of Staphylococcus aureus strains that are resistant to rifamycins. This collection of resistant strains contains 21 of the 26 known single-amino-acid alterations in RpoB, the target of rifamycins. Some NCEs also demonstrated a lower frequency of resistance development than rifampin and rifalazil in S. aureus as measured in a resistance emergence test. When assayed for activity against the strongest rifamycin-resistant mutants, several NCEs had MICs of 2 g/ml, in contrast to MICs of rifampin and rifalazil, which were 512 g/ml for the same strains. The properties of these NCEs therefore demonstrate a significant improvement over those of earlier rifamycins, which have been limited primarily to combination therapy due to resistance development, and suggest a potential use of these NCEs for monotherapy in several clinical indications.

Novel rifamycins (new chemical entities [NCEs]) having MICs of 0.002 to 0.03 g/ml against Staphylococcus aureus and retaining some activity against rifampin-resistant mutants were tested for in vivo efficacy against susceptible and rifampin-resistant strains of S. aureus. Rifalazil and rifampin had a 50% effective dose (ED 50 ) of 0.06 mg/kg of body weight when administered as a single intravenous (i.v.) dose in a murine septicemia model against a susceptible strain of S. aureus. The majority of NCEs showed efficacy at a lower i.v. dose (0.003 to 0.06 mg/kg). In addition, half of the NCEs tested for oral efficacy had ED 50 s in the range of 0.015 to 0.13 mg/kg, i.e., lower or equivalent to the oral ED 50 s of rifampin and rifalazil. NCEs were also tested in the septicemia model against a rifampin-resistant strain of S. aureus. Twenty-four of 169 NCEs were efficacious when administered as a single oral dose of 80 mg/kg. These NCEs were examined in the murine thigh infection model against a susceptible strain of S. aureus. Several NCEs dosed by intraperitoneal injection at 0.06 mg/kg caused a significant difference in bacterial titer compared with placebo-treated animals. No NCEs showed efficacy in the thigh model against a highly rifampin-resistant strain. However, several NCEs showed an effect when tested against a partially rifampin-resistant strain. The NCEs having a 25-hydroxyl moiety were more effective as a group than their 25-O-acetyl counterparts. These model systems defined candidate NCEs as components of potential combination therapies to treat systemic infections or as monotherapeutic agents for topical applications.Rifalazil [3Ј-hydroxy-5Ј-(4-isobutyl-1-piperazinyl) benzoxazinorifamycin], also referred to as KRM-1648 or ABI-1648, is a rifamycin derivative with exceptionally low MICs against gram-positive bacteria (7,19), Helicobacter pylori (1), and Chlamydia (9,18,21,22). The potency of rifalazil and the other rifamycins derives from their specific inhibition of bacterial RNA polymerase (6). Preclinical animal studies suggest that rifalazil has efficacy against Chlamydia pneumoniae (9), Clostridium difficile (2), Mycobacterium tuberculosis (8,19,20), and Staphylococcus aureus (7). In addition, rifalazil has been tested in phase 2 human clinical trials for the treatment of tuberculosis (5) L-992b, 2004). One of the attributes of rifamycins, including rifalazil, is the propensity for resistance to develop as a result of the occurrence of mutations in the rpoB gene. These mutations cause modifications in the binding site of the target enzyme, the ␤ subunit of RNA polymerase, in pathogens such as M. tuberculosis (13, 17, 25, 26), S. aureus (23, 24), and Streptococcus pyogenes (3). Thus, rifamycins have been confined primarily to multiple-drug therapy where resistance development is less of an issue.Recently, we described a collection of over 700 novel rifamycins which are related in structure to rifalazil. More than 50% of these new chemical entities (NCEs) are more active against gram-positive bacteri...