The correlation between patient characteristics and expectations of benefit from Phase I clinical trials

BACKGROUND: Patients in Phase I clinical trials sometimes report high expectations regarding the benefit of treatment. The authors examined a range of patient characteristics to determine which factors were associated with greater expectations of benefit from Phase I trials. METHODS: Participants were adult patients with cancer who had been offered participation in Phase I studies and had decided to participate. Patients completed interviewer-administered surveys before initiation of treatment. Physicians assessed Eastern Cooperative Oncology Group performance status for each patient. Statistical analyses (Pearson product moment correlation and t tests) used multiple imputation to account for missing data. RESULTS: Overall, 593 patients who were offered participation in Phase I trials were contacted, and 328 patients agreed to participate in a study of decision making by cancer patients. Of these, 260 patients (79%) enrolled in a Phase I trial. Patients' expectations regarding the chance that their disease would be controlled with experimental therapy were unrelated to age, gender, living situation, education level, or functional status. Expectations were correlated positively with beliefs about the benefit of standard therapy and the maximum benefit patients may experience from experimental therapy. Greater expectations of benefit were associated with better health-related quality of life, stronger religious faith, optimism, relative health stock, monetary risk seeking, and poorer numeracy. CONCLUSIONS: Expectations expressed as beliefs in personal outcomes may be related more to quality of life and personality variables than to patients' knowledge or functional status. Whether such expectations are accurate reflections of knowledge has important implications for evaluating the informed consent process.     

Evaluating a campaign to detect early stage breast tumors in the United States

Growing concern over failure to detect early stage breast cancer has led communities across the United States to participate in the Breast Cancer Awareness Month program. This program mobilizes local public and private institutions, particularly the media, to reach a large audience each October with information on salutary behaviors, including screening, and on resources that can assist newly motivated audiences to adopt the behaviors. Although the scholarly literature includes no assessments of the effect of the program on the actual detection of early stage breast tumors, similar programs targeting other illnesses (e.g., AIDS) are quickly emerging. We attempt such an assessment by applying time-series designs to 92 quarters (beginning January, 1975) of data obtained from cancer registries in the Atlanta and Detroit metropolitan areas as well as in the San Francisco Bay Area. We find that the detection of in situ and local breast tumors increased in all three communities during the quarters that included Breast Cancer Awareness Month. We conclude that community mobilization may have its intended benefit but suggest that community organizers not ignore unintended costs including the emotional and physical sequelae of false positives.     

Baclofen antagonizes intravenous self-administration of nicotine in mice and rats

AIMS: Gamma-aminobutyric acid (GABA)-ergic transmission plays an important role in modulating reinforcing effects of different drugs of misuse. In particular, stimulation of GABA(B) receptors negatively influences self-administration of cocaine, heroin, nicotine, alcohol and gamma-hydroxybutyric acid. The effect and specificity of the GABA(B) agonist baclofen on nicotine misuse were studied on two animal models of self-administration. METHODS: The effects of RS baclofen and the two isomers R baclofen and S baclofen were studied on the acute nicotine self-administration in drug-na?ve mice. The effect of RS baclofen was also studied in rats trained to chronically self-administer nicotine under a continuous reinforcement (FR1) schedule. RESULTS: RS baclofen antagonizes nicotine intravenous self-administration at doses of 1.25-2.5 mg/kg intraperitoneally (i.p.). Furthermore, this effect is sterospecific. R baclofen completely prevented nicotine self-administration at the dose of 0.625 mg/kg i.p., whereas S baclofen was inactive up to the dose of 2.5 mg/kg i.p. In rats trained to self-administer nicotine, pretreatment with RS baclofen at the dose of 2.5 mg/kg i.p. significantly increased the rate of responding for nicotine. This effect was similar to the effect obtained when rats were pretreated with the nicotine central receptor antagonist mecamylamine (1 mg/kg i.p.). CONCLUSIONS: These data show that baclofen is able to antagonize nicotine-rewarding effects in mice and rats and suggest its potential clinical utility for the treatment of nicotine misuse.     

Persistent organic pollutants in food: public health implications

Persistent organic pollutants are a heterogeneous group of chemicals sharing a number a common properties, including long term persistence and diffusion in the environment, and bioaccumulation through the food chain. Animal experiments and epidemiological studies suggest that the most sensitive adverse effects, such as disturbances on metabolism, development, and reproductive system, may occur in the range of current human exposure. Although the potential cancer risk of persistent organic pollutants remains undefined, the implementation of actions to reduce the exposure to these substances, which mainly occurs through the diet, is important.     

Possible enhancement of the first-pass metabolism of phenacetin by ingestion of grape juice in Chinese subjects

AIMS: This serendipitous study revealed an unexpected effect of Jufeng grape juice on the CYP1A2-mediated metabolism of phenacetin. Investigation of the inhibition of CYP1A2 by grapefruit juice was involved but a translation error led to the grape juice substitution. METHODS: Twelve healthy subjects took a single oral dose of phenacetin (900 mg) on two randomized occasions together with 200 ml water or grape juice. Plasma phenacetin and paracetamol concentrations were assessed by h.p.l.c. RESULTS: Ingestion of grape juice was associated with reduced plasma phenacetin concentrations, while paracetamol levels were unaffected. Paracetamol to phenacetin AUC ratios increased from 13.9+/-3.1 to 24.3+/-3.8 after ingestion of grape juice. CONCLUSIONS: These findings suggest enhanced first-pass metabolism of phenacetin, due to CYP1A2 activation by grape juice or to desaturation of CYP1A2 isoenzymes secondary to a slower rate of phenacetin absorption.     

Relative potency values derived from hepatic vitamin A reduction in male and female Sprague-Dawley rats following subchronic dietary exposure to individual polychlorinated dibenzo-p-dioxin and dibenzofuran congeners and a mixture thereof

This study investigated the potency of individual polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) to reduce hepatic vitamin A in the rat. Dose-response relationships were determined following long-term dietary exposure to 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7, 8-pentachlorodibenzofuran, 1,2,3,4,8-pentachlorodibenzofuran, 1,2,3, 7,8-pentachlorodibenzofuran, 1,2,3,6,7,8-hexachlorodibenzofuran, 1,2, 3,7,8-pentachlorodibenzo-p-dioxin, octachlorodibenzo-p-dioxin, octachlorodibenzofuran, or mixtures of some of these congeners. The aim was to estimate vitamin A-related relative potency (REP) values for each congener in relation to that of TCDD and to investigate if these values were in accordance with REP values estimated for the subchronic toxicity observed in the same study. An additional aim was to investigate if the effect on hepatic vitamin A levels was additive compared to the effect of the individual congeners. The obtained results demonstrate that hepatic vitamin A reduction occurs as a consequence of long-term low-level exposure to 2,3,7, 8-substituted but not to non-2,3,7,8-substituted congeners. Female rats were slightly more responsive to this effect as judged from the lower EC50 values for all the congeners in this sex. The vitamin A-related REP values were similar for female and male rats and were in good agreement with the estimated REP values for subchronic toxicity in the same animals. The vitamin A effect of the individual congeners in the mixture tended to be somewhat less than pure additive for male rats and very close to pure additive for female rats. In conclusion, the presented data show that reduction of hepatic vitamin A is a sensitive marker of an altered retinoid homeostasis following long-term low-dose exposure to dioxin-like compounds, which essentially conforms to their assumed additive mechanism of action.     

The cyclo-oxygenase inhibitor nimesulide induces conditioned place preference in rats

Two cyclo-oxygenase inhibitors, indomethacin and nimesulide, have been shown to potentiate morphine-induced stimulation of meso-accumbens dopamine neurons. In this study, an unbiased conditioned place preference procedure was used to evaluate whether nimesulide produces motivational effect after systemic administration in rats. These results show that nimesulide, at doses 0.1, 0.5 and 1 mg/kg, even lower than those usually applied for inflammatory conditions, induces conditioned place preference in rats, suggesting that it might possess rewarding properties in humans.