ATAC - Pharmacokinetics (PK) Sub-Protocol

A Randomised, Double Blind Trial to Assess the Pharmacokinetics of Arimidex Alone, Nolvadex Alone, or Arimidex and Nolvadex in Combination, When Used as Adjuvant Treatment for Breast Cancer in Postmenopausal Women

Status

Completed

Phases

Phase 3

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT00784862

Enrollment

9358

Registered

2008-11-04

Start date

1998-06-30

Completion date

1999-03-31

Last updated

2009-05-15

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Breast Cancer

Brief summary

To assess the effect of ARIMIDEX on the pharmacokinetics of tamoxifen and the effects of tamoxifen on the pharmacokinetics of ARIMIDEX..

Interventions

DRUGAnastrozole

1mg, orally, once daily

DRUGTamoxifen

20mg, orally, once daily

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

DOUBLE (Subject, Investigator)

Eligibility

Sex/Gender

FEMALE

Age

45 Years to No maximum

Healthy volunteers

Inclusion criteria

* Eligible for entry into the main ATAC trial 1033IL/0029 * Patients must have been taking ATAC trial medication for at least 3 months (i.e. patients must have reached at least visit 2 of the main ATAC study) * Patients should be taking their medication in the mornings for at least 3 months * Patients must be 100% compliant over the preceding fourteen days

Exclusion criteria

* Excluded from entry into the main ATAC trial (1033IL/0029) * Patients whose concurrent treatment includes diazepam or drugs which might affect tamoxifen steady state levels or steroid hormone status. These include ketoconazole (antifungal) or related compounds

Design outcomes

Primary

Measure	Time frame
Steady state plasma trough concentrations of tamoxifen, desmethyltamoxifen and anastrozole	24±4 hours after previous dose

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026