High-dose pentoxifylline in patients with AIDS: inhibition of tumor necrosis factor production. National Institute of Allergy and Infectious Diseases AIDS Clinical Trials Group

Tumor necrosis factor-alpha (TNF) may activate human immunodeficiency virus (HIV), antagonize zidovudine activity, and contribute to AIDS wasting syndrome. Pentoxifylline decreases TNF production. In cell culture, pentoxifylline decreases HIV replication and gene expression. Since an AIDS Clinical Trial Group study suggested that pentoxifylline (400 mg thrice daily) is safe in AIDS patients and decreases TNF mRNA levels in peripheral blood mononuclear cells (PBMC), a second cohort received 800 mg thrice daily for 8 weeks. During treatment, the median decrease in TNF production by PBMC cultured with 0.1 microgram/mL lipopolysaccharide (LPS) was 40%. The median change in TNF mRNA was a 34% decrease. Pentoxifylline did not affect HIV levels as detected by quantitative microculture or serum p24 antigen measurements, nor did it alter zidovudine pharmacokinetics. The most common toxicity was gastrointestinal. Pentoxifylline at dosages of less than thrice-daily 800 mg is well tolerated and may decrease TNF mRNA levels and LPS-induced TNF production.

A rapid screening system to determine drug affinities for the intestinal dipeptide transporter 2: affinities of ACE inhibitors

PURPOSE

To assess the affinities of a series of ACE inhibitors for the di/tri/oligopeptide transport system (DTS) using a rapid in vitro system.

METHODS

Monolayers of Caco-2 cells were cultured in plastic wells for 7-9 days and the uptake of Gly-[3H]L-Pro was used as an affinity probe. Gly-[3H]L-Pro (50 nM), together with excess L-Pro (10 mM), to suppress uptake of any [3H]L-Pro produced by degradation of the probe, was incubated with the test compound (usually 1 mM) at pH 6 for 3-mins. The uptake of radiolabel was determined by liquid scintillation counting.

RESULTS

A 2-dimensional six-domain model of the transporter based on the structure of a phosphinate ACE inhibitor (SQ-29852) was constructed to facilitate interpretation of the competitor affinities. The SQ-29852 molecule was divided into six binding domains (A-F) based on functional groups within these regions and the effects of structural variation in four of these domains (A, C-E) were explored. A series of dipeptide-like compounds varying within specific domains were selected from a large number of commercially available ACE inhibitors and SQ-29852 analogues. Domain A had a preference for an uncharged group, with bulky hydrophobic groups reducing affinity. Domain C exhibited a preference for a positive charge over a neutral function, with the space this functional group occupies contributing to affinity. Domain D favoured lipophilic residues and domain E retained activity when the carboxylic acid was esterified.

CONCLUSION

The test system is able to reveal structure-activity relationships of peptidomimetic agents and may well serve as a design tool to optimise affinity for the DTS.

Cost effectiveness of olanzapine in prevention of affective episodes in bipolar disorder in the United Kingdom

This study evaluated the cost effectiveness of olanzapine compared with lithium as maintenance therapy for patients with bipolar I disorder (BP1) in the UK. A Markov model was developed to assess costs and outcomes from the perspective of the UK National Health Service over a 1-year period. Patients enter the model after stabilization of a manic episode and are then treated with olanzapine or lithium. Using the findings of a recent randomized clinical trial, the model considers the monthly risk of manic or depressive episodes and of dropping out from allocated therapy. health care resources associated with acute episodes were derived primarily from a recent UK chart review. Costs of maintenance therapy and monitoring were also considered. Key factors influencing cost effectiveness were identified and included in a stochastic sensitivity analysis. The model estimated that, compared to lithium, olanzapine significantly reduced the annual number of acute mood episodes per patient from 0.81 to 0.58 (difference -0.23; 95% CI: -0.34, -0.12). Per patient average annual care costs fell by 799 UK pounds (95% CI: - 1,824 UK pounds, 59 UK pounds) driven by reduced inpatient days--but the cost difference was not statistically significant. Sensitivity analysis found the results to be robust to plausible variation in the model's parameters. The model estimated that using olanzapine instead of lithium as maintenance therapy for BP1 would significantly reduce the rate of acute mood events resulting in reduced hospital costs. Based on available evidence, there is a high likelihood that olanzapine would reduce costs of care compared to lithium.

A rapid screening system to determine drug affinities for the intestinal dipeptide transporter 1: system characterisation

PURPOSE

To establish an in vitro system for the rapid assessment of the affinities of potential substrates for the di/tri/oligopeptide transport system (DTS).

METHODS

Monolayers of Caco-2 cells were cultured in plastic wells for 7-9 days and the uptake of Gly-[3H]L-Pro, a specific and relatively stable substrate for the DTS was used as an affinity probe. Gly-[3H]L-Pro (50 nM), together with excess L-Pro (10 mM), to suppress uptake of any [3H]L-Pro produced by degradation of the probe, was incubated with the test compound (usually 1 mM) at pH 6 for 3 min. The uptake of radiolabel was determined by liquid scintillation counting.

RESULTS

High specific-uptake (> 85%) of Gly-[3H]L-Pro was obtained with cells grown for 7-9 days. Gly-[3H]L-Pro uptake had a substantial active concentration-dependent component (Km of 0.39 +/- 0.02 mM, Vmax of 0.98 +/- 0.04 nmol min(-1) (mg protein)(-1). This process was shown to be specific for the DTS as evidenced by the significant inhibition by compounds reported to be transported by this system and the lack of inhibition by amino acids. The use of low competitor concentrations (1 mM) enabled a range of inhibition values (0-89%) of a series of competitors (amino acids, dipeptides and beta-lactam antibiotics) to be estimated, illustrating that structurally similar compounds can be ranked for affinity to the DTS.

CONCLUSION

A screening system, using Caco-2 cells and the dipeptide Gly-[3H]L-Pro as a displaceable probe, was developed to assess a variety of compounds for recognition by the di/tri/oligopeptide transport system. This fully describes the first system that allows structurally related compounds to be ranked on the basis of their affinity for the DTS recognition site.

Prodrugs of BMS-183920: metabolism and permeability considerations

The oral bioavailability of BMS-183920, a diacidic, potent angiotensin II receptor antagonist, is low in rats (approximately 11%). In vivo studies in bile duct-cannulated rats indicated that BMS-183920 was metabolically stable and that the low bioavailability was due to incomplete intestinal absorption. Five acyl-ester prodrugs were synthesized which were 5-15 times more permeable than BMS-183920 through Caco-2 cells. However, limited studies in rats indicated that the oral bioavailability of BMS-183920 was improved only 2-fold, in the best case. The lack of a substantial increase in bioavailability was apparently due to presystemic prodrug hydrolysis or metabolism via N-glucuronidation. Bioavailability of BMS-183920 after oral dosing of a tetrazole-ester prodrug averaged 37%, the most significant improvement within this prodrug series. Interestingly, in vitro studies indicated that the tetrazole-ester prodrug was a substrate for glucuronosyl transferase; however, its rate of bioactivation (hydrolysis) was sufficiently high to provide a substantial increase in bioavailability of BMS-183920. Therefore, while prodrug modification of BMS-183920 improved Caco-2 cell permeability and oral absorption in vivo, the relative extents of hydrolysis (bioactivation) vs metabolism of the prodrug determined whether a substantial improvement in bioavailability was achieved.

Distribution of the dipeptide transporter system along the gastrointestinal tract of rats based on absorption of a stable and specific probe, SQ-29852

Peptidic drugs such as beta-lactam aminocephalosporin antibiotics (e.g., cephalexin) and the ACE inhibitors lisinopril, quinapril, and benzazepril are apparently absorbed, at least in part, by the intestinal dipeptide transporter system (DTS). Although many properties of the DTS have been elucidated, including isolation of the carrier protein, little is known about the distribution of this transporter along the gastrointestinal (GI) tract. The objectives of the present study were to (1) validate that SQ-29852 (a lysylproline ACE inhibitor) is a stable and specific probe for evaluation of the DTS in rats and (2) provide fundamental in vivo information on the distribution of the DTS along the GI tract of rats. Most of the previous studies that explored the location of the DTS typically involved either in vitro uptake or in situ disappearance of unstable or nonspecific probes. SQ-29852, on the other hand, is an ideal probe for evaluation of the DTS because it is chemically and metabolically stable and it is absorbed almost exclusively by the DTS. SQ-29852 appears to be a specific probe for the DTS because the dose-dependent reduction in absorption from about 60% to less than 8% (3 and 3000 mg/kg, respectively) suggests that at least 85% of an orally administered low dose of SQ-29852 is absorbed by a saturable process, which was shown previously to be the DTS. [14C]SQ-29852 was administered by gavage to intact rats and via an indwelling cannula in one of the following sections of the intestine: duodenum, jejunum, ileum and proximal colon (n = 4 for each site). On the basis of the recovery of [14C]SQ-29852 in urine, the DTS is apparently distributed throughout the entire GI tract of rats, including the proximal colon. The present results are consistent with previously reported results on the absorption of natural dipeptides in humans and rats and immunohistochemical evaluation in rats; however, they disagree with a recent report in humans with amoxicillin. This difference is discussed in terms of the specificity and stability of various drugs that have been used as probes of the DTS.

Abstract P6-12-14: Quality of life and ability to work in patients at different disease stages of HER2+ breast cancer

OBJECTIVES: Health-related quality of life (HRQoL) and ability to work in patients treated for HER2+ early breast cancer (EBC) are poorly understood. This study compared HRQoL and ability to work in 3 HER2+ patient cohorts: EBC during adjuvant treatment, EBC after treatment, and metastatic disease (MBC).

METHODS: A cross-sectional observational cohort study of 299 female consenting patients with HER2+BC, from 14 UK secondary care centres. Group1 (n=89): receiving targeted HER2 therapy±chemotherapy for EBC; Group2 (n=108): in follow up post-targeted treatment for eBC; Group3 (n=102): MBC on treatment. Data collected between Dec 2016-Mar 2017: HRQoL, demographic and employment status data collected via patient-reported questionnaires (including EQ-5D-5L and Functional Assessment of Cancer Therapy [FACT-B]); clinical data collected from medical records. Inter-group differences were assessed using univariate Analysis of variance (ANOVA) and chi-square tests as appropriate. [NCT03099200].

RESULTS: Table1 shows patient demographics, disease characteristics, employment status, and EQ-5D-5L scores. Group1 and Group2 patients did not differ in overall health utility or visual analogue scale (VAS) scores. However, Group3 patients reported significantly poorer health utility than Group1 (p<0.02) and Group2 (p<0.001), and significantly worse VAS scores than Group2 (p<0.001). Significantly fewer Group2 patients and more Group3 patients were unable to work (p<0.003), and fewer Group3 patients were employed than expected (by chi-square, p<0.003).

CONCLUSIONS: HRQoL in patients with EBC was similar whether on or off treatment, and better than those with MBC. HRQoL scores reported on the generic EQ-5D will be compared with those from the disease-specific FACT-B. A smaller proportion of patients with MBC were employed compared to the EBC groups, reflecting the impact of advanced disease. Fewer patients with EBC reported being unable to work than we expected, suggesting these patients maintain function.

Table1

 Group1 (n=89)Group2 (n=108)Group3 (n=102)Age (years)↑55 (11)58 (11)55 (11)Hormone receptor status¥Positive64 (72%)84 (78%)74 (73%)Negative25 (28%)24 (22%)26 (26%)Unknown0 (0%)0 (0%)2 (2%)Time since diagnosis (months)+EBC9 (6)45 (32) (n=103)80 (82) (n=71*)MBC--39 (36) (n=101)Employment status¥Employed45 (51%)55 (51%)28 (28%)§Not employed41 (46%)52 (48%)69 (68%)Retired22 (25%)39 (36%)33 (32%)Unable to work7 (8%)5 (5%)§27 (27%)§Other12 (14%)8 (7%)9 (9%)Unknown3 (3%)1 (1%)5 (5%)EQ-5D summary scoresVisual analogue scale72.7 (18.4)†77.0 (17.5)†65.8 (22.9)† (n=99)Utility value0.809 (0.170)† (n=86)0.818 (0.181)†0.695 (0.262)† (n=97)↑mean (standard deviation); ¥n (%); +median (interquartile range); *excludes 27/102 patients (27%) with de novo MBC. Bold text: observed differences between three groups at significance thresholds of ‡p<0.05, §p<0.003 or †p<0.001. EBC/MBC: early/metastatic breast cancer. %s have been rounded so may not total 100%

Citation Format: Verrill M, Wardley A, Retzler J, Smith AB, McNicol D, Dando S, Tran I, Leslie I, Schmid P. Quality of life and ability to work in patients at different disease stages of HER2+ breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-12-14.

[Improved product characteristics of nicotine gums: an unexplored area for higher compliance with nicotine replacement therapy]

OBJECTIVE

To assess consumer acceptance of new flavoured nicotine gums in comparison with existing nicotinegums.

METHOD

A total of 607 adult smokers who intended to cut down or give up smoking were included in two randomised, single-blind, central location, acceptance tests. A new fruit-flavoured nicotine gum (Gum A = Nicorette Freshfruit) was compared with an existing fruit-flavoured nicotine gum (Gum B = Nicotinell fruit), and a new menthol-flavoured gum (Gum N = Nicorette Icy White) was compared with two existing mint-flavoured gums (Gum M = Nicotinell mint; Gum Q = NiQuitin mint). For all gums, the nicotine 2 mg and 4 mg strengths were tested. Each subject compared two of the nicotine gums, either 2 mg or 4 mg and either fruit-flavoured or menthol/ mint-flavoured, and assessed several characteristics, including sweetness, flavour, crunchiness, and overall liking, at predefined intervals.

RESULTS

For the fruit-flavoured gums the percentage of subjects who rated sweetness and flavour to be "just right"after 5 minutes of chewing was significantly higher for Gum A than for Gum B at both strengths. Comparison of the mint/menthol-flavoured gums revealed significantly superior ratings for Gum N over both Gum M and Gum Q. With regard to expectations of which gum would be more likely help quit smoking, significantly more participants expressed greater confidence in Gum A than Gum B for the fruit-flavoured gums. Similarly, for the mint/menthol-flavoured gums significantly more subjects had greater confidence in Gum N than Gum Mor Gum Q.

CONCLUSIONS

Product characteristics of nicotine gums, such as crunchiness, sweetness and flavour, appear to be crucial for the expectations that smokers have in the likelihood that any particular nicotine gum will help them to quit smoking. Thus, improved organoleptic characteristics of nicotine gums may lead to higher compliance, resulting in higher plasma nicotine levels and thereby in a higher quit rate.

L-2-oxothiazolidine-4-carboxylic acid (procysteine) inhibits expression of the human immunodeficiency virus and expression of the interleukin-2 receptor alpha chain

These studies were undertaken to examine the in vitro effects of the cysteine pro-drug L-2-oxothiazolidine-4-carboxylic acid (Procysteine) on human immunodeficiency virus expression. Procysteine inhibited HIV expression in human peripheral blood mononuclear cells as detected by measurement of supernatant core antigen. In transient transfection assays, Procysteine inhibited gene expression controlled by the HIV-1 promoter in activated Jurkat cells but not in resting Jurkat cells. Gel-shift assays showed that Procysteine inhibited NF-kappa B DNA binding activity in nuclear extracts. Procysteine did not affect the production of interleukin-2 by peripheral blood mononuclear cells of healthy HIV-seronegative subjects, as measured by bioassay but it decreased the density of cell-surface interleukin-2 receptors detected by flow cytometry after stimulation with phytohemagglutinin (PHA). Thus, Procysteine inhibits HIV expression, HIV promoter activity, and NF-kappa B binding activity in vitro. Procysteine does not affect interleukin-2 production but inhibits interleukin-2 receptor expression in PHA-stimulated peripheral blood mononuclear cells.