Patiromer for the management of hyperkalemia in heart failure with reduced ejection fraction: the DIAMOND trial.

AIMS: To investigate the impact of patiromer on the serum potassium level and its ability to enable specified target doses of renin-angiotensin-aldosterone system inhibitor (RAASi) use in patients with heart failure and reduced ejection fraction (HFrEF). METHODS AND RESULTS: A total of 1642 patients with HFrEF and current or a history of RAASi-related hyperkalemia were screened and 1195 were enrolled in the run-in phase with patiromer and optimization of the RAASi therapy [≥50% recommended dose of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker/angiotensin receptor-neprilysin inhibitor, and 50 mg of mineralocorticoid receptor antagonist (MRA) spironolactone or eplerenone]. Specified target doses of the RAASi therapy were achieved in 878 (84.6%) patients; 439 were randomized to patiromer and 439 to placebo. All patients, physicians, and outcome assessors were blinded to treatment assignment. The primary endpoint was between-group difference in the adjusted mean change in serum potassium. Five hierarchical secondary endpoints were assessed. At the end of treatment, the median (interquartile range) duration of follow-up was 27 (13-43) weeks, the adjusted mean change in potassium was +0.03 mmol/l in the patiromer group and +0.13 mmol/l in the placebo group [difference in the adjusted mean change between patiromer and placebo: -0.10 mmol/l (95% confidence interval, CI -0.13, 0.07); P < 0.001]. Risk of hyperkalemia >5.5 mmol/l [hazard ratio (HR) 0.63; 95% CI 0.45, 0.87; P = 0.006), reduction of MRA dose (HR 0.62; 95% CI 0.45, 0.87; P = 0.006), and total adjusted hyperkalemia events/100 person-years (77.7 vs. 118.2; HR 0.66; 95% CI 0.53, 0.81; P < 0.001) were lower with patiromer. Hyperkalemia-related morbidity-adjusted events (win ratio 1.53, P < 0.001) and total RAASi use score (win ratio 1.25, P = 0.048) favored the patiromer arm. Adverse events were similar between groups. CONCLUSION: Concurrent use of patiromer and high-dose MRAs reduces the risk of recurrent hyperkalemia (ClinicalTrials.gov: NCT03888066).

Lack of Exposure in a First-in-Man Study Due to Aldehyde Oxidase Metabolism: Investigated by Use of 14C-microdose, Humanized Mice, Monkey Pharmacokinetics, and In Vitro Methods.

Inclusion of a microdose of 14C-labeled drug in the first-in-man study of new investigational drugs and subsequent analysis by accelerator mass spectrometry has become an integrated part of drug development at Lundbeck. It has been found to be highly informative with regard to investigations of the routes and rates of excretion of the drug and the human metabolite profiles according to metabolites in safety testing guidance and also when additional metabolism-related issues needed to be addressed. In the first-in-man study with the NCE Lu AF09535, contrary to anticipated, surprisingly low exposure was observed when measuring the parent compound using conventional bioanalysis. Parallel accelerator mass spectrometry analysis revealed that the low exposure was almost exclusively attributable to extensive metabolism. The metabolism observed in humans was mediated via a human specific metabolic pathway, whereas an equivalent extent of metabolism was not observed in preclinical species. In vitro, incubation studies in human liver cytosol revealed involvement of aldehyde oxidase (AO) in the biotransformation of Lu AF09535. In vivo, substantially lower plasma exposure of Lu AF09535 was observed in chimeric mice with humanized livers compared with control animals. In addition, Lu AF09535 exhibited very low oral bioavailability in monkeys despite relatively low clearance after intravenous administration in contrast to the pharmacokinetics in rats and dogs, both showing low clearance and high bioavailability. The in vitro and in vivo methods applied were proved useful for identifying and evaluating AO-dependent metabolism. Different strategies to integrate these methods for prediction of in vivo human clearance of AO substrates were evaluated.

Negative clinical results from a randomised, double-blind, placebo-controlled trial evaluating the efficacy of two doses of immunologically enhanced, grass subcutaneous immunotherapy despite dose-dependent immunological response.

OBJECTIVE: Specific immunotherapy is the only treatment for the underlying allergic disease in patients with respiratory allergies. The primary objective of this trial was to evaluate the efficacy and safety of two maintenance doses of immunologically enhanced, standardised quality (SQ+) grass subcutaneous immunotherapy (SCIT) [4,000 SQ+ and 15,000 SQ+; AVANZ(®) Phleum pratense (ALK)] compared with placebo. METHODS: This was a randomised, double-blind, placebo-controlled, phase II/III trial. The primary evaluation was based on the combined rhinoconjunctivitis score during the entire grass pollen season. Adult subjects with grass pollen-induced allergic rhinoconjunctivitis interfering with usual activities or sleep despite symptomatic medication use, were enrolled. RESULTS: Four hundred and fifty subjects were randomised to receive either 4,000 SQ+ (n = 150), 15,000 SQ+ (n = 152) or placebo (n = 148). The average grass pollen exposure was 27 grains/m(3)/day. No statistically significant differences between the active groups and the placebo group were found for clinical endpoints (p > 0.05). Highly statistically significant (p < 0.001) increases in IgG4 and IgE-blocking factor were found for both active groups versus placebo. The most frequently reported adverse events were mild-to-moderate local injection-site reactions; events were generally more frequent with 15,000 SQ+ than with 4,000 SQ+ and placebo. The most common adverse events leading to premature discontinuation from the trial were anaphylactic reactions (one subject from the placebo group and five subjects from the 15,000 SQ+ group). CONCLUSIONS: The inconclusive results were most probably influenced by a very low grass pollen season. Other factors such as the extent of the pre-seasonal treatment could potentially have contributed. The tolerability profile was acceptable for further development.

Impact of low-level fluoroquinolone resistance genes qnrA1, qnrB19 and qnrS1 on ciprofloxacin treatment of isogenic Escherichia coli strains in a murine urinary tract infection model.

OBJECTIVES: To study the impact of qnrA1, qnrB19 and qnrS1 on the ciprofloxacin treatment of urinary tract infection (UTI). METHODS: From a wild-type (wt) Escherichia coli UTI isolate, three isogenic strains were constructed carrying low-level ciprofloxacin resistance genes qnrA1, qnrB19 or qnrS1 (ciprofloxacin MIC range: 0.19-0.38 mg/L). Time-kill studies were performed for all four isogenic strains at the following concentrations: 1×, 2×, 4×, 8× and 16× MIC. Ciprofloxacin serum and urine pharmacokinetics was determined to calculate a murine dose equivalent (AUC(24)) to the standard human dose of 500 mg twice daily, which corresponded to 0.2 mg/mouse four times daily. In the murine UTI model, mice infected with each of the isogenic qnr strains or the wt strain were treated with ciprofloxacin (0.2 mg/mouse) or saline (only the E. coli wt) subcutaneously four times daily for 3 days starting 24 h after bacterial inoculation. RESULTS: In vitro, the strains responded to ciprofloxacin concentrations of 4-16× MIC by several log(10) reductions. In vivo, despite ciprofloxacin reaching urine concentrations far exceeding the MICs for the strains (500 mg/L), ciprofloxacin was significantly less efficient at reducing the urine and bladder bacterial counts of qnrA1-, qnrB19- and qnrS1-positive strains compared with the ciprofloxacin-treated wt strain (P < 0.05). None of the four strains infected the kidneys well, with median cfu counts of <1 log(10). CONCLUSIONS: Although qnr genes only confer low levels of resistance to ciprofloxacin, a reduced bactericidal activity of ciprofloxacin was observed in both urine and bladder in the murine model of UTI.

Synthesis and characterization of water-soluble free-base, zinc and copper porphyrin-oligonucleotide conjugates.

We describe the synthesis and characterization of a series of water-soluble free-base, zinc, and copper porphyrin-oligonucleotide (ODN) conjugates. A non-charged tetraarylporphyrin was directly attached to the 5'-position of thymine via a short amide linker. Such a linker should allow for rigid connection to the adjacent nucleobases, thus increasing the sensitivity for monitoring conformational changes of the ODNs by electronic circular dichroism due to capping effects or ligand binding. Two complementary synthetic approaches have been used to incorporate porphyrin chromophores into the DNA. In the first approach a porphyrin carboxylic acid is conjugated to 5'-amino-ODN. In the second approach the phosphoramidite of the porphyrin-amido-thymidine is coupled to 5'-hydroxy-ODN using standard automated phosphoramidite chemistry. In both cases a spontaneous metallation of the free-base porphyrin in porphyrin-DNA conjugates was observed during the porphyrin-DNA conjugate cleavage from the solid support and its consequent deprotection using concentrated aqueous ammonia. Zinc and copper porphyrin-DNA conjugates were isolated by HPLC and characterized together with the anticipated free-base porphyrin-DNA conjugate. Authentic zinc and copper porphyrin-DNA conjugates were intentionally prepared from intentionally metallated porphyrins to compare their spectroscopic and HPLC characteristics with isolated metallospecies and to confirm the spontaneous metallation.

New alpha(1)-adrenoceptor antagonists derived from the antipsychotic sertindole - carbon-11 labelling and pet examination of brain uptake in the cynomolgus monkey.

Central alpha(1)-adrenergic receptors are potential targets for recently developed antipsychotic drugs. Two new 11C labeled potent and selective alpha(1)-adrenoceptor antagonists, 1- [2- [4-[1-(4-fluorophenyl)-5-(2-[(11)C]methyl-tetrazol-5-yl)-1H-indol-3-yl]-1-piperidinyl]ethyl]-imidazolidin-2-one ([(11)C]2) and 1- [2- [4-[1-(4-fluorophenyl)-5-(1-[(11)C]methyl-(1,2,3-triazol-4-yl)-1H-indol-3-yl]-1-piperidinyl]ethyl]-imidazolidin-2-one ([(11)C]3) were prepared and evaluated for imaging of central alpha(1)-adrenergic receptors in the cynomolgus monkey brain. For both compounds, the total brain radioactivity was only about 0.6% of the radioactivity injected i.v. There was no evident binding in regions known to contain alpha(1)-adrenoceptors. This observation suggests that the affinity of the radioligands in primates in vivo is not sufficient to provide a signal for specific binding that can be differentiated from the background. In addition, active efflux by P-glycoprotein may be responsible for the low total brain-uptake of the two radioligands. Both compounds showed a highly polarised and verapamile sensitive transport across monolayers of Caco-2 cells. The total brain-uptake of [(3)H]2 was 6 times higher in mdr1a(-/-) knock-out mice lacking the gene encoding P-glycoprotein compared to wild type mice. Pretreatment of one monkey with Cyclosporin A (15 mg/kg) resulted in 40% higher brain uptake for [(11)C]3 when compared with baseline. These observations support the view that efflux by P-glycoprotein can be of quantitative importance for the total brain-uptake of some PET radioligands.