8 (��=0.05). We decided inhibitor bulk to end the study with slightly less CC patients (n=9), because we were not able to recruit more patients despite extensive efforts. Statistical analysis The effects of CDCA ingestion on GB volumes and FGF 19 levels during the first 6 hrs and potential differences between the two patient groups were compared by repeated measures ANOVA with Bonferroni correction. Differences between individual time points within each group were assessed by a paired t-test. Baseline characteristics and various individual parameters for GB dynamics, FGF19 dynamics and faecal bile acid excretion were compared between the two groups (patients with CC and disease controls) using Mann-Whitney U tests.
For analysis of gene expression, fold-change relative to a group of untreated disease controls was compared between CDCA-treated CC patients and disease controls using a Mann-Whitney U test. Correlations between FGF19 levels and GB volumes or fecal bile acid excretion were explored by Spearman correlation. A two-sided P-value <0.05 was considered statistically significant. Statistical analysis was performed using SPSS 15.0. Results Clinical patient characteristics Between September, 2009 and May, 2011 a total of nine patients with quiescent CC and 14 disease controls were enrolled in this study. Inclusion was not consecutive since only 23 of the potential 129 candidates consented to follow the demanding protocol and met the inclusion criteria (Figure 1). Two disease controls were included but did not receive CDCA, since baseline gallbladder volumes could not be reliably assessed with ultrasound.
These patients were excluded from further analysis. Mean age was 51 years (��SD 15) in CC patients and 50 years (��SD 12) in disease controls. Six CC patients (67%) and six disease controls (50%) were of male gender. In the CC group, mean duration of disease was 20 years (SD ��10). Mean weight and BMI were respectively 75 kilograms (��SD 11) and 23.6 (��SD 2.2) in CC patients and 79 kilograms (��SD 15) and 24.8 (��SD 2.7) in disease controls. None of these characteristics were significantly different between the two groups. Disease characteristics of CC patients during previous and current colonoscopies are given in Table 1. In one patient from each patient group, the cecum was not reached and biopsies could therefore not be taken. In the short study period compliance with CDCA ingestion (based on pill counts at day 
was 100% in all patients (taking in account dose reductions performed by the physician because of perceived side effects), except one who had by accident been Dacomitinib taking one pill less for one day. Mean cumulative CDCA dose was 111 mg/kg * 8days (��SD 13.4) in CC patients and 117 mg/kg * 8 days (��SD 9.90) in disease controls (p=0.26).