The EPIC-Norfolk Study
Ocular effects of fenretinide, a vitamin A analog, in a chemoprevention trial of bladder cancer.
Cancer detection and prevention 2000 ; 24: 369-75.
Baglietto L, Torrisi R, Arena G, Tosetti F, Gonzaga AG, Pasquetti W, Robertson C, and Decensi A
PubMed ID : 11059568
PMCID :
URL : https://pubmed.ncbi.nlm.nih.gov/11059568/
Abstract
Fenretinide is a vitamin A derivative under investigation in cancer prevention trials. Because all available pharmacologic and toxicologic data were obtained from breast cancer patients, we measured plasma drug, metabolite, and vitamin A levels and studied their relationship with visual and ocular symptoms in a cohort formed mostly by male subjects belonging to a bladder cancer prevention trial. After 1 year, the mean plasma retinol levels (+/- standard deviation [SD]) were 168.2 +/- 75.8 ng/ml in 31 subjects treated with fenretinide and 594.5 +/- 168.4 ng/ml in 36 control subjects (P < .001). Plasma retinol levels were correlated inversely to drug and metabolite concentrations, which in turn were correlated inversely to the interval from last drug intake. The decline of plasma vitamin A levels accounted for a 41.7% cumulative incidence of diminished dark adaptability in the retinoid arm as compared to 6.8% in the control arm (odds ratio = 13.8; 95% confidence interval, 2.9-66.1). Although compliance as assessed by capsule count was high, three subjects originally assigned to the treatment group who proved to be noncompliers (8.8%, or 3 of 34) had no detectable plasma drug or metabolite levels. Our data confirm the specific pharmacologic and visual effects of fenretinide also in a male population and strengthen the importance of multiple blood measurements to monitor treatment compliance in prevention trials.