The effect of food on the pharmacokinetics of oral ibrutinib in healthy participants and patients with chronic lymphocytic leukemia.

Purpose: To assess ibrutinib pharmacokinetics under fasted and fed conditions, impact of food-intake timing, and the safety and tolerability.

Methods: Three studies were analyzed. Study 1 was a randomized, open-label, single-dose, four-way crossover study in 44 healthy participants.

Population pharmacokinetic model of ibrutinib, a Bruton tyrosine kinase inhibitor, in patients with B cell malignancies.

Purpose: Ibrutinib is an oral Bruton's tyrosine kinase inhibitor, recently approved for the treatment of mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) patients with at least one prior therapy. We developed a population pharmacokinetic (PK) model for ibrutinib in patients.

Methods: Ibrutinib PK data (3,477 observations/245 patients) were available from the following clinical studies: (1) A phase I dose-escalation study in recurrent B cell malignancies (dose levels of 1.

Pharmacokinetic/pharmacodynamic modelling-based optimisation of administration schedule for the histone deacetylase inhibitor abexinostat (S78454/PCI-24781) in phase I.

Abexinostat, an oral pan-histone deacetylase inhibitor (HDACi), was evaluated in patients with advanced solid tumours in two single agent phase I studies (PCYC-402 and CL1-78454-002). In PCYC-402 study testing four different administration schedules, the maximum tolerated dose (MTD) was established at 75 mg/m(2) BID (twice daily) and the recommended dose at 60 mg/m(2) BID regardless of the schedule tested. The dose limiting toxicity (DLT), consistently observed across all these schedules, was reversible thrombocytopenia.

The Bruton tyrosine kinase inhibitor PCI-32765 blocks B-cell activation and is efficacious in models of autoimmune disease and B-cell malignancy.

Activation of the B-cell antigen receptor (BCR) signaling pathway contributes to the initiation and maintenance of B-cell malignancies and autoimmune diseases. The Bruton tyrosine kinase (Btk) is specifically required for BCR signaling as demonstrated by human and mouse mutations that disrupt Btk function and prevent B-cell maturation at steps that require a functional BCR pathway. Herein we describe a selective and irreversible Btk inhibitor, PCI-32765, that is currently under clinical development in patients with B-cell non-Hodgkin lymphoma.

Quinazolinone fungal efflux pump inhibitors. Part 3: (N-methyl)piperazine variants and pharmacokinetic optimization.

Further structure-activity relationships of a novel series of fungal efflux pump inhibitors with respect to potentiation of the activity of fluconazole against strains of C. albicans and C. glabrata over-expressing ABC-type efflux pumps are systematically explored.

Development of protegrins for the treatment and prevention of oral mucositis: structure-activity relationships of synthetic protegrin analogues.

Protegrin antimicrobial peptides possess activity against gram-positive and gram-negative bacteria and yeasts. An extensive structure-activity relationship (SAR) study was conducted on several hundred protegrin analogues to gain understanding of the relationship between the primary and secondary structure of the protegrins and their antimicrobial activities, and to identify a protegrin analogue for clinical development. Native sequence protegrins are cationic, amphiphilic peptides that are characterized by the presence of a beta-sheet structure that is maintained by two disulfide bridges.

Characterization of the muscarinic receptor in isolated uterus of sham operated and ovariectomized rats.

1. The pharmacological characteristics of muscarinic receptors in rat isolated uterus were studied in ovariectomized (ov.) and sham operated (sh.

Effect of local application of the antimicrobial peptide IB-367 on the incidence and severity of oral mucositis in hamsters.

Objective: The purpose of this animal study was to determine whether IB-367, an antimicrobial peptide, is able to ameliorate oral mucositis by reducing microflora densities on the mucosal surfaces of the mouth.

Study Design: Oral mucositis was induced in hamsters by intraperitoneal injection of 5-fluorouracil followed by superficial abrasion of the buccal mucosa. A test formulation was applied topically to the buccal mucosa 5 or 6 times per day starting 6 to 8 hours before abrasion.

Protegrin-1: a broad-spectrum, rapidly microbicidal peptide with in vivo activity.

Protegrin-1 (PG-1) is a cysteine-rich, 18-residue beta-sheet peptide isolated from porcine leukocytes with antimicrobial activity against a broad range of microorganisms. The MICs of PG-1 against representative gram-positive and gram-negative bacteria ranged from 0.12 to 2 microg/ml.

[3H]RS 57639, a high affinity, selective 5-HT4 receptor partial agonist, specifically labels guinea-pig striatal and rat cloned (5-HT4S and 5-HT4L) receptors.

RS 57639, by being a partial agonist in rat esophagus but a competitive antagonist in guinea-pig ileum, is one of several ligands which operationally discriminate among 5-HT4 receptors in different tissues. The discovery of splice variants of the 5-HT4 receptor, 5-HT4S and 5-HT4L, raises the possibility that this functional heterogeneity among 5-HT4 receptors may be due to differences in the interaction of ligands with different isoforms of the receptor. To test this idea, the functional and binding interactions of RS 57639 with rat 5-HT4S and 5-HT4L receptors were characterized.

Functional role of M2 and M3 muscarinic receptors in the urinary bladder of rats in vitro and in vivo.

1. Urinary bladder smooth muscle is enriched with muscarinic receptors, the majority of which are of the M2 subtype whereas the remaining minority belong to the M3 subtype. The objective of the present study was to assess the functional role of M2 and M3 receptors in the urinary bladder of rat in vitro and in vivo by use of key discriminatory antagonists.

The beta 1 sodium channel subunit modifies the interactions of neurotoxins and local anesthetics with the rat brain IIA alpha sodium channel in isolated membranes but not in intact cells.

Mammalian brain sodium channels consist of an alpha subunit and two smaller beta subunits. The role of the beta 1 subunit in modulating ligand interactions at these channels was examined using a cell line stably expressing human beta1 and rat brain IIA alpha subunits. Coexpression of the beta 1 subunit had no effect on the potencies of sodium channel blockers in inhibiting whole cell [3H]batrachotoxinin A benzoate ([3H]BTX) binding or veratridine-stimulated [14C]guanidinium influx.

Allosteric interactions among agonists and antagonists at 5-hydroxytryptamine3 receptors.

Cooperation in the action of agonists suggests that there are multiple binding sites on 5-hydroxytryptamine3 (5-HT3) receptors. The purpose of this study was to characterize these binding sites and their interactions on both native and cloned 5-HT3 receptors. The affinities of competitive 5-HT3 receptor antagonists were similar regardless of whether the receptors were labeled with [3H]RS-42358, [3H]granisetron, or 1-(m-[3H]chlorophenyl)biguanide ([3H]mCPG).

The interaction of RS 25259-197, a potent and selective antagonist, with 5-HT3 receptors, in vitro.

1. A series of isoquinolines have been identified as 5-HT3 receptor antagonists. One of these, RS 25259-197 [(3aS)-2-[(S)-1-azabicyclo[2.

[3H]RS-23597-190, a potent 5-hydroxytryptamine4 antagonist labels sigma-1 but not sigma-2 binding sites in guinea pig brain.

Recent findings have suggested a relationship between 5-hydroxytryptamine (5-HT)4 receptors and sigma binding sites. To test this idea, the affinity of 5-HT4 receptor ligands for sigma binding sites was examined. In contrast to the 5-HT4 receptor ligands BIMU-1 [endo-N-(8-methyl-8-azabicyclo[3.

[3H]BIMU-1, a 5-hydroxytryptamine3 receptor ligand in NG-108 cells, selectively labels sigma-2 binding sites in guinea pig hippocampus.

The binding of [3H]endo-N-(8-methyl-8-azabicyclo[3.2.1.

Different densities of 5-HT3 receptors are labeled by [3H]quipazine, [3H]GR 65630 and [3H]granisetron.

The binding of three, structurally distinct, 5-hydroxytryptamine3 (5-HT3) receptor radioligands was characterized in rat cerebral cortex, rabbit ileum myenteric plexus and NG-108-15 neuroblastoma cells. The density of sites labeled by the three ligands in rat cortex or in rabbit ileum was markedly different. [3H]Quipazine labeled more sites than [3H]GR 65630 in rat cortex (4.

Serum epoxide hydrolase (preneoplastic antigen) in human and experimental liver injury.

Reports of an increase in a serum epoxide hydrolase (sEH), immunochemically related to microsomal EH in humans and rats with hepatocellular carcinoma (HCC), suggested its use as a serum marker for this disease. We have now measured sEH levels (as either immunochemically determined content or enzyme activity) in a number of human and experimental models of liver disease. sEH was elevated above the normal range in at least 50% of individuals with HCC, including: 3 of 6 northern Californians; 4 of 7 Koreans with hepatitis B-associated HCC; hepatitis B-associated HCC in woodchucks; and male rats receiving chronic treatment with aflatoxin B1 or ciprofibrate.

Characteristics of 5-HT3 binding sites in NG108-15, NCB-20 neuroblastoma cells and rat cerebral cortex using [3H]-quipazine and [3H]-GR65630 binding.

1. The biochemical and pharmacological properties of 5-HT3 receptors in homogenates of NG108-15 and NCB-20 neuroblastoma cells and rat cerebral cortex have been ascertained by the use of [3H]-quipazine and [3H]-GR65630 binding. 2.

Assessment of imiloxan as a selective alpha 2B-adrenoceptor antagonist.

1. The alpha 2-adrenoceptor binding sites of rabbit spleen and rat kidney, labelled with [3H]-rauwolscine, were characterized using a range of subtype selective ligands. 2.

Differences between the alpha 2-adrenoceptor in rat submaxillary gland and the alpha 2A-and alpha 2B-adrenoceptor subtypes.

1. The alpha 2-adrenoceptors of rat submaxillary gland, labelled with [3H]-rauwolscine, were characterized by use of a range of subtype selective ligands and were compared to rabbit spleen alpha 2A-adrenoceptors and rat kidney alpha 2B-adrenoceptors. 2.

Identification of a single alpha 1-adrenoceptor corresponding to the alpha 1A-subtype in rat submaxillary gland.

1. The alpha 1-adrenoceptors present in membranes of rat liver, cortex and submaxillary gland were labelled with [3H]-prazosin and the affinity of 15 ligands for these receptors was determined. 2.

Use of primary cultures of human hepatocytes in toxicology studies.

Often results from toxicological studies using rodent models cannot be directly extrapolated to probable effects in human beings. In order to examine the genotoxic potential of chemicals in human liver cells, a human hepatocyte DNA repair assay has been defined. Procedures were optimized to prepare primary cultures of human hepatocytes from discarded surgical material.

Sodium cholate extraction of rat liver nuclear xenobiotic-metabolizing enzymes.

DNA is the purported target of several carcinogenic and mutagenic agents. Nuclear enzymes which could generate or detoxify reactive metabolites are of major concern. Several such enzymes have been identified within nuclei, but obtaining samples with enriched content or activity is difficult, time-consuming, and uses harsh isolation techniques.