PharmacoKINEtics of TAMoxifen and Its Metabolites in Breast Cancer Patients: the Influence of a Dose Increase in Phenotypic Poor Metabolizers of CYP2D6 (KINETAM)

• Status: Completed
• Trial end date: 2012-05-01
• Target enrollment: 0
• Participant gender: Female

Summary

All women on tamoxifen receive the standard dose of 20mg QD, irrespective of the use of potential CYP2D6 inhibitors, and are not tested for CYP2D6 polymorphisms prior to start of tamoxifen treatment.However CYP2D6 polymorphisms and/or the use of CYP2D6 inhibitors as co-medication may influence the treatment outcome of tamoxifen.

The investigators propose a prospective study in women taking tamoxifen at a dose of 20mg QD. In each woman, information will be collected on endoxifen levels, CYP2D6 status, adherence and use of co-medication. In women who are phenotypically poor metabolizers of tamoxifen, a dose increase to 40mg QD will be applied and the effect of this intervention on tamoxifen pharmacokinetics will be evaluated after 4 weeks.

• Phase: Phase 1
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: Radboud University
• Treatments: Tamoxifen

Criteria

Inclusion Criteria:

• Subject is at least 18 years at screening.

• Subject is able and willing to sign the Informed Consent Form prior to screening evaluations.

• Subject is a female patient with (a history of) breast cancer and has been treated with tamoxifen 20mg QD for at least 4 weeks and is expected to be treated for at least another 4 weeks

Exclusion Criteria:

• Inability to understand the nature and extent of the trial and the procedures required.

• Participation in a drug trial within 60 days prior to the first dose.