Tamoxifen Response by CYP2D6 Genotype-Based Treatment in Patients with Metastatic or Recurrent Breast Cancer

Tamoxifen Response by CYP2D6 Genotype-Based Treatment in Patients with Metastatic or Recurrent Breast Cancer - TARGET-1 study

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

JPRN

Registry ID

JPRN-UMIN000009155

Enrollment

180

Registered

2012-10-20

Start date

2016-09-14

Completion date

Unknown

Last updated

2026-06-29

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

Conditions

Hormone receptor-positive metastatic or recurrent breast cancer

Interventions

CYP2D6 wt/wt : 20mg/day for 24 weeks CYP2D6 wt/V or V/V : 20mg/day for 24 weeks CYP2D6 wt/V or V/V : 40mg/day for 24 weeks

Eligibility

Sex/Gender

Female

Inclusion criteria

Inclusion criteria: 1) Metastatic or recurrent breast cancer 2) Estrogen-receptor positive 3) Patients who are planning to undergo tamoxifen treatment for the primary treatment breast cancer 4) Patients having measurable target lesions 5) ECOG performance status (PS) 0-1 6) Patients having no severely impaired main organs and marrow 7) Patients who are expected to survive more than 6 months after the first registration day 8) Patients must receive an adequate explanation of the trial before enrollment and sign a written informed consent document

Exclusion criteria

Exclusion criteria: 1) HER2 status positive 2) Prior endocrine therapy for recurrent or metastatic disease 3) Prior chemotherapy for recurrent or metastatic disease 4) Patients having active double cancer 5) Patients having CNS metastasis 6) Patients receiving continuous systemic administration of steroids 7) Patients receiving prohibited concomitant medications 8) Patients having difficulty to enroll to the study for psychiatric reasons 9) Patients who are pregnant (or might be pregnant), nursing, or those who will not use contraceptive methods 10) Other cases determined as being unsuitable by the investigators

Design outcomes

Primary

Measure	Time frame
Progression free rate at 6 months after the patient randomization	—

Secondary

Measure	Time frame
1) Response rate (CR+PR) 2) Clinical benefit (CR+PR + SD for longer than 6 months) 3) Relationship between trough levels of tamoxifen, endoxifen, 4-hydroxytamoxifen and N-desmethyltamoxifen at steady state and efficacy and/or adverse reactions 4) Exploration of factors affecting the response	—

Countries

Japan

Contacts

Public ContactKenji Tamura

National Cancer Center Hospital Department of Breast and Medical Oncology

ketamura@ncc.go.jp03-3542-2511

Outcome results

None listed

Source: JPRN (via WHO ICTRP) · Data processed: Jul 3, 2026