A phase 2a study of topical perillyl alcohol cream for chemoprevention of skin cancer.

The chemopreventive and antitumor properties of perillyl alcohol (POH) that were studied preclinically indicate that topical POH inhibits both UVB-induced murine skin carcinogenesis (squamous cell tumor models) and 7,12-dimethylbenz(a)anthracene-induced murine melanoma (transgenic models involving tyrosinase-driven Ras). A previous phase 1 clinical trial in participants with normal-appearing skin showed that topical POH cream was well tolerated at a dose of 0.76% (w/w). Here, we performed a 3-month, double-blind, randomized, placebo-controlled phase 2a trial of two different doses of topical POH in individuals with sun-damaged skin. Participants applied POH cream twice daily to each dorsal forearm. Baseline and end-of-study biopsies were taken from each participant to evaluate whether the topical application of POH was effective in reversing actinic damage as evidenced by normalization of quantitative skin histopathologic scores and change in nuclear chromatin pattern as measured by karyometric analysis. There was a borderline reduction in the histopathologic score of the lower-dose POH group compared with the placebo (P = 0.1), but this was not observed in the high-dose group. However, in the high-dose group, a statistically significant reduction in the proportion of nuclei deviating from normal was observed by the use of karyometric analysis (P < 0.01). There was no statistical significance shown in the lower-dose group. No changes were observed in p53 expression, cellular proliferation (by proliferating cell nuclear antigen expression), or apoptosis in either treatment group compared with the placebo group. These results suggest that whereas our karyometric analyses can detect a modest effect of POH in sun-damaged skin, improved delivery into the epidermis may be necessary.

Results of a phase I multiple-dose clinical study of ursodeoxycholic Acid.

BACKGROUND: The hydrophilic bile acid, ursodeoxycholic acid (UDCA), may indirectly protect against colon carcinogenesis by decreasing the overall proportion of the more hydrophobic bile acids, such as deoxycholic acid (DCA), in aqueous phase stool. In the AOM rat model, treatment with UDCA resulted in a significant decrease in adenoma formation and colorectal cancer. It was hypothesized that there is a dose-response relationship between treatment with the more hydrophilic bile acid, UDCA, and a reduction in the proportion of the more hydrophobic bile acid, DCA, in the aqueous stool phase, suggesting the potential of UDCA as a chemopreventive agent. METHODS: Eighteen participants were randomized to 300, 600, or 900 mg/day UDCA for 21 days in this multiple-dose, double-blinded study. Seventy-two-hour stool samples were collected pretreatment and on days 18-20 of UDCA treatment for bile acid measurements. Pharmacokinetics were performed and blood bile acids were measured at days 1 and 21 of UDCA treatment. RESULTS: There were no serious adverse events associated with UDCA treatment. There was a dose-response increase in the posttreatment to baseline ratio of UDCA to DCA from the 300 mg/day to the 600 mg/day group, but not between the 600 and the 900 mg/day groups, in both aqueous and solid phase stool. This posttreatment increase was statistically significant in aqueous phase stool for the 300 and 600 mg/day treatment groups (P = 0.038 and P = 0.014, respectively), but was only marginally significant in the 900 mg/day treatment group (P = 0.057). Following the first dose administration, a dose-dependent increase in plasma ursodeoxycholic concentrations was observed in fasting subjects; however, when these levels were measured postprandially following 3 weeks of treatment, the areas under the plasma concentration-time profile (AUC) were not statistically different and remained relatively unchanged over time. CONCLUSIONS: UDCA treatment did not decrease the quantity of DCA in fecal water or solids; however, it did decrease the proportion of DCA in fecal water and solids in relation to UDCA. Thus, 3 weeks of UDCA treatment resulted in an overall increase in hydrophilicity of bile acids in the aqueous phase stool, with a peak effect observed with a daily dose of 600 mg/day. Much larger studies are needed to determine the effect of ursodeoxycholic administration on deoxycholic concentration, overall hydrophilicity of stool bile acids, and the long-term effects on intermediate biomarkers of cellular damage.

Fecal bile acid concentrations in a subpopulation of the wheat bran fiber colon polyp trial.

Factors that affect the concentration of secondary bile acids in the aqueous phase of stool may have a greater impact on colon carcinogenesis than those that only modify the total fecal bile acid concentration. This hypothesis was tested using stool samples of a subset of participants enrolled in a Phase III colorectal adenomatous polyp prevention trial, which documented the inability of a 13.5 g/day wheat bran fiber (WBF) supplement to reduce polyp recurrence. Stool was collected from 68 consecutively consented participants who were enrolled in a Phase III clinical trial of WBF for the prevention of adenomatous polyp recurrence. Nineteen (27.9%) of these fecal bile acid substudy participants were on the low fiber (2.0 g/day) intervention group, whereas 49 (72.7%) were on the high fiber (13.5 g/day) intervention group for approximately 3 years. Sixty-four participants had both the aqueous and solid phases of stool samples analyzed for bile acid content. Bile acid concentrations, measured in microg/ml for fecal water and microg/mg for dry feces, were determined for lithochilic, deoxycholic, chenodeoxycholic, cholic, ursodeoxycholic, isodeoxycholic, isoursodeoxycholic, ursocholic, 7-ketolithocholic, and 12-ketolithocholic acids. There were no significant differences between the low and high fiber groups concerning mean or median aqueous phase concentrations of lithocholic or deoxycholic bile acids. In contrast, the median concentrations of deoxycholic acid and other secondary bile acids (including lithochilic, isodeoxycholic, ursodeoxycholic, isoursodeoxycholic, ursocholic, 7-ketolithocholic, and 12-ketolithocholic acids) were significantly lower for the high fiber group in the solid-phase stool (P < 0.05). These results document that a high WBF intervention, taken for a median of 2.4 years, does not significantly reduce aqueous-phase concentrations of secondary bile acids in stool, although their concentrations in solid-phase stool were suppressed. Thus, the inability of the high WBF intervention to reduce colorectal adenoma recurrence may be a consequence of its lack of effect on fecal aqueous-phase secondary bile acid concentrations.