Glucuronidation by UGT1A1 Is the Dominant Pathway of the Metabolic Disposition of Belinostat in Liver Cancer Patients

10.1371/journal.pone.0054522PLoS ONE81

'Risky' research and participants' interests: The ethics of phase 2C clinical trials

Biomedical research involving human participants is highly regulated and subject to stringent ethical requirements. Clinical research ethics, regulation and policy have tended to focus almost exclusively on the protection of participants' interests against harms that might result from taking part in research. Less consideration, however, has been given to the interests that patients may themselves have in research participation, even in trials that may be beyond the bounds of current clinical research practice. In this paper, we consider the case of a suggested extension to clinical trial protocols to explore the ethics of participation in ‘risky’ research. We argue that patients may have a strong interest in taking part in research, and that even when greater-than-usual risks may be present, such research can be both ethically and scientifically justified. Finally, we suggest that there might be scope in some cases to assert a right to participate in research, and that the possibility of such a right merits further consideration. </jats:p

Glucuronidation by UGT1A1 Is the Dominant Pathway of the Metabolic Disposition of Belinostat in Liver Cancer Patients

Belinostat is a hydroxamate class HDAC inhibitor that has demonstrated activity in peripheral T-cell lymphoma and is undergoing clinical trials for non-hematologic malignancies. We studied the pharmacokinetics of belinostat in hepatocellular carcinoma patients to determine the main pathway of metabolism of belinostat. The pharmacokinetics of belinostat in liver cancer patients were characterized by rapid plasma clearance of belinostat with extensive metabolism with more than 4-fold greater relative systemic exposure of major metabolite, belinostat glucuronide than that of belinostat. There was significant interindividual variability of belinostat glucuronidation. The major pathway of metabolism involves UGT1A1-mediated glucuronidation and a good correlation has been identified between belinostat glucuronide formation and glucuronidation of known UGT1A1 substrates. In addition, liver microsomes harboring UGT1A1*28 alleles have lower glucuronidation activity for belinostat compared to those with wildtype UGT1A1. The main metabolic pathway of belinostat is through glucuronidation mediated primarily by UGT1A1, a highly polymorphic enzyme. The clinical significance of this finding remains to be determined.ClinicalTrials.gov NCT00321594</p