Virginia L. Wyss

Drotrecogin alfa (activated) in patients with severe sepsis presenting with purpura fulminans, meningitis, or meningococcal disease: a retrospective analysis of patients enrolled in recent clinical studies

IntroductionWe report data from adult and pediatric patients with severe sepsis from studies evaluating drotrecogin alfa (activated) (DrotAA) and presenting with purpura fulminans (PF), meningitis (MEN), or meningococcal disease (MD) (PF/MEN/MD). Such conditions may be associated with an increased bleeding risk but occur in a relatively small proportion of patients presenting with severe sepsis; pooling data across clinical trials provides an opportunity for improving the characterization of outcomes.MethodsA retrospective analysis of placebo-controlled, open-label, and compassionate-use trials was conducted. Adult patients received infusions of either DrotAA or placebo. All pediatric patients (<18 years old) received DrotAA. 189 adult and 121 pediatric patients presented with PF/MEN/MD.ResultsFewer adult patients with PF/MEN/MD met cardiovascular (68.3% versus 78.8%) or respiratory (57.8% versus 80.5%) organ dysfunction entry criteria than those without. DrotAA-treated adult patients with PF/MEN/MD (n = 163) had an observed 28-day mortality rate of 19.0%, a 28-day serious bleeding event (SBE) rate of 6.1%, and an intracranial hemorrhage (ICH) rate of 4.3%. Six of the seven ICHs occurred in patients with MEN (three of whom were more than 65 years old with a history of hypertension). DrotAA-treated adult patients without PF/MEN/MD (n = 3,088) had an observed 28-day mortality rate of 25.5%, a 28-day SBE rate of 5.8%, and an ICH rate of 1.0%. In contrast, a greater number of pediatric patients with PF/MEN/MD met the cardiovascular organ dysfunction entry criterion (93.5% versus 82.5%) than those without. DrotAA-treated PF/MEN/MD pediatric patients (n = 119) had a 14-day mortality rate of 10.1%, an SBE rate of 5.9%, and an ICH rate of 2.5%. DrotAA-treated pediatric patients without PF/MEN/MD (n = 142) had a 14-day mortality rate of 14.1%, an SBE rate of 9.2%, and an ICH rate of 3.5%.ConclusionDrotAA-treated adult patients with severe sepsis presenting with PF/MEN/MD had a similar SBE rate, a lower observed 28-day mortality rate, and a higher observed rate of ICH than DrotAA-treated patients without PF/MEN/MD. DrotAA-treated pediatric patients with severe sepsis with PF/MEN/MD may differ from adults, because all three outcome rates (SBE, mortality, and ICH) were lower in pediatric patients with PF/MEN/MD.

Cardiac inotropic responses to calcium and forskolin are not altered by prolonged isoproterenol infusion.

Effects of prolonged isoproterenol infusion upon the density of cardiac calcium channels, calcium-mediated contractile responses, and the ability of forskolin to enhance tension development and cyclic AMP accumulation were studied in ventricular muscle preparations from Sprague-Dawley rats. Isoproterenol infusion (400 micrograms/kg per h s.c., 4 days) significantly decreased calcium channel density (Bmax) in cardiac microsomal membranes as quantified by a 32% decrease in specific [3H]nitrendipine binding sites; binding affinity (KD) was unchanged. A 57% decrease of beta-adrenoceptors confirmed homologous down regulation. To examine functional effects of decreased [3H]nitrendipine binding sites, responses to calcium, BAY K8644 and nifedipine were determined in isolated right ventricular strips. Significant decreases in basal developed tension were observed in muscles from isoproterenol-infused rats. However, concentration-dependent increases in contractility in response to CaCl2 or BAY K8644 were comparable, and the negative inotropic effect of nifedipine was unchanged. Whereas isoproterenol infusion was associated with significantly decreased basal cardiac cyclic AMP concentrations, exposure of ventricular strips from either vehicle- or isoproterenol-infused rats to 10 microM forskolin resulted in comparable increases in cyclic AMP and in developed tension. Cumulative, submaximal concentrations of forskolin also produced similar increases in contractility with maximum responses in ventricular strips from vehicle-infused animals attained at 4.4 microM forskolin. Higher concentrations resulted in automaticity. By contrast, ventricle from isoproterenol-infused animals responded to 14.4 microM forskolin with maximal increases in force of contraction.

Fused bicyclic Gly-Asp β-turn mimics with potent affinity for GPIIb-IIIa. Exploration of the arginine isostere

6-[4-Amidinobenzoyl]amino]-tetralone-2-acetic acid is a potent antagonist of GPIIb-IIIa. Substitution in the meta position of the benzamidine, or replacement with a heteroaryl amidine was tolerated in this series. Use of an acyl-linked 4-alkyl piperidine as an arginine isostere also provided active compounds. Compounds from this series provided substantial systemic exposure in the rat following oral administration.

Cardiovascular effect and stimulus-dependent inhibition of superoxide generation from human neutrophils by tibenelast, 5,6-diethoxybenzo(b) thiophene-2-carboxylic acid, sodium salt (LY186655)☆

Tibenelast (LY186655), 5,6,-diethoxybenzo(b)thiophene-2-carboxylic acid, sodium salt, is an orally active anti-anaphylactic compound in guinea pigs, and has been shown to prevent bronchospasm in moderately severe asthmatic patients. Pharmacological studies with tibenelast demonstrated that it is a selective phosphodiesterase (PDE) inhibitor in that it is moderately active against the lung and stomach enzyme while being a very weak inhibitor of the heart enzyme. The compound was without cardiovascular effects at anti-anaphylactic doses. In contrast to theophylline, tibenelast did not have a direct inotropic effect in the cat papillary muscle system. The concentration that inhibited 50% of the enzymatic activity (IC50) for tibenelast was 20- to 30-fold lower for neutrophil PDE than for PDE of other tissues. It was 100 times more potent than aminophylline in inhibiting superoxide generation from platelet-activating factor (PAF)-primed polymorphonuclear leukocytes (PMNL) challenged with chemotactic factor, N-formyl-methionyl-leucyl-phenylalanine. However, tibenelast was less effective in the tumor necrosis factor-primed system, and did not inhibit superoxide generation during phagocytosis or when other soluble stimuli, such as phorbo-12-myristate-13-acetate or the calcium ionophore A23187, were used. Furthermore, tibenelast did not inhibit enzymes involved in arachidonic acid metabolism. These results suggest that tibenelast probably inhibits superoxide release from PMNL via a selective inhibition on PDE.

Development of dual-acting agents for thromboxane receptor antagonism and thromboxane synthase inhibition. 2. Design, synthesis, and evaluation of a novel series of phenyl oxazole derivatives

Synthesis and initial in vitro evaluation of a novel series of phenyl oxazole derivatives are described. An SAR study of the novel dual-acting TRA/TSI agent has revealed that the lipophilicity of the oxazole amide substituents greatly influences the TRA activity but not the TSI. The chain length of the alkenoic acid side chain affects both TRA and TSI. The optimal chain length for the combined activities was found to be n = 4 (heptenoic acid).