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NCT Number: NCT01075802

Study of Tamoxifen Dose Escalation in Breast Cancer Patients With CYP2D6 Polymorphisms

Tamoxifen is an important drug for the treatment of breast cancer. Used adjuvantly after operation in early breast cancer, tamoxifen reduces annual recurrence rate by half and cancer death by one third. Used preventatively it also reduces the risk of breast cancer by 50% in women at high risk for developing the disease Tamoxifen needs to be activated in the body to an active form called endoxifen, mainly by the enzyme called CYP2D6. Patients have variable capability to activate tamoxifen due to variable function of this enzyme. Studies showed clear correlation of specific genetic variant of CYP2D6 with endoxifen blood levels. It is estimated that up to 25% Caucasian population have reduced or even absent CYP2D6 function. More recently, there were studies that showed the correlation with genetic variant of CYP2D6 and breast cancer relapse in early breast cancer patients treated with tamoxifen. Food and Drug Authority (FDA) in America and recommended checking CYP2D6 genotype in patients receiving tamoxifen treatment, but they did not specify how to interpret the genotype results and what kind actions to take in patient with adverse genotype. The aim of the investigators study is to see if increasing tamoxifen in patients with genetic polymorphism of CYP2D6 will increase endoxifen level to the same range of most patients who have wild type (normal functional)CYP2D6.

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Key information

Conditions

Breast Cancer Breast Diseases Breast Neoplasms CYP2D6 Polymorphism Neoplasms Neoplasms by Site Skin Diseases Skin and Connective Tissue Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

St George Hospital, Sydney, New South Wales, Australia

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • ECOG performance status ≤ 1
  • Life expectancy ≥ 6 months
  • Histologically or cytologically confirmed early, locally advanced or metastatic breast cancer
  • Oestrogen receptor positive
  • About to start tamoxifen treatment or already on tamoxifen 20mg daily
  • Adequate hepatic and renal function

Exclusion criteria

  • Concurrent chemotherapy or radiotherapy
  • Treatment with medications that may alter cytochrome P450 (CYP450)3A4/5 and CYP2D6 activities
  • History of thrombosis
  • History of non-compliance with previous or current treatment;
  • Medical or psychiatric conditions that compromise the patient's ability to give informed consent

Treatment and study plan

Tamoxifen

Drug

Dose escalation

Primary outcomes

  1. Effects of genotype of CYP2D on plasma and serum concentration of tamoxifen and its metabolites, with consequent recommendation for dosage adjustment

    Time frame: dose escalation over 40 weeks

  2. To test whether Tamoxifen dose escalation in patients with genetic polymorphism of CYP2D6 will increase endoxifen blood levels to a target level

    Time frame: Dose escalation over 40 weeks

  3. Correlate tamoxifen and its metabolites concentration with tamoxifen side effects

    Time frame: dose escalation over 40 weeks

Sponsors and collaborators

Lead sponsor

Western Sydney Local Health District

Other

Collaborators

  • St George Hospital, Australia

Registry information

Official study title

A Multi-Centre Study of Tamoxifen Dose Escalation Study in Breast Cancer Patients With CYP2D6 Polymorphisms

Acronym: TADE

Important dates

Study start
2010
Primary completion
2012
Study completion
2012
First posted
Feb 25, 2010
Registry last updated
May 6, 2013

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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