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Tamoxifen (open label)
Tamoxifen is a selective estrogen receptor modulator (SERM) that blocks estrogen signaling in breast tissue by competitively binding to estrogen receptors.
Tamoxifen is a selective estrogen receptor modulator (SERM) that blocks estrogen signaling in breast tissue by competitively binding to estrogen receptors. Used for Metastatic breast cancer, estrogen receptor-positive, Adjuvant treatment of early-stage breast cancer, estrogen receptor-positive, Breast cancer risk reduction in high-risk women.
At a glance
| Generic name | Tamoxifen (open label) |
|---|---|
| Also known as | Nolvadex, Genox, Tamifen |
| Sponsor | Oregon Health and Science University |
| Drug class | Selective estrogen receptor modulator (SERM) |
| Target | Estrogen receptor alpha (ERα) |
| Modality | Small molecule |
| Therapeutic area | Oncology |
| Phase | FDA-approved |
Mechanism of action
Tamoxifen acts as an antagonist at estrogen receptors in breast cancer cells, preventing estrogen-driven proliferation. In other tissues such as bone and endometrium, it can exhibit partial agonist activity. This selective modulation makes it effective for both treatment and prevention of estrogen receptor-positive breast cancer.
Approved indications
- Metastatic breast cancer, estrogen receptor-positive
- Adjuvant treatment of early-stage breast cancer, estrogen receptor-positive
- Breast cancer risk reduction in high-risk women
Common side effects
- Hot flashes
- Vaginal discharge
- Nausea
- Vaginal bleeding
- Endometrial cancer
- Thromboembolic events
- Cataracts
Key clinical trials
- A Study of Elacestrant Versus Standard Endocrine Therapy in Women and Men With ER+,HER2-, Early Breast Cancer With High Risk of Recurrence (PHASE3)
- A Study of Imlunestrant (LY3484356) in Premenopausal Women With Estrogen Receptor-Positive (ER+) Human Epidermal Growth Factor Receptor 2 Negative (HER2-) Early Breast Cancer (PHASE2)
- A Phase III Trial Comparing HRS-8080 With Standard Endocrine Therapy in Patients With High-Risk Early Breast Cancer (PHASE3)
- Letrozole, Anastrozole, Exemestane, or Tamoxifen Citrate in Treating Postmenopausal Women With Breast Cancer (PHASE3)
- A Study of MK-5684 in People With Certain Solid Tumors (MK-5684-015/OMAHA-015) (PHASE2)
- A Study of Camizestrant in ER+/HER2- Early Breast Cancer After at Least 2 Years of Standard Adjuvant Endocrine Therapy (PHASE3)
- Phase 2 Study of Amcenestrant (SAR439859) Versus Physician's Choice in Locally Advanced or Metastatic ER-positive Breast Cancer (PHASE2)
- A Study Evaluating the Efficacy and Safety of Adjuvant Giredestrant Compared With Physician's Choice of Adjuvant Endocrine Monotherapy in Participants With Estrogen Receptor-Positive, HER2-Negative Early Breast Cancer (lidERA Breast Cancer) (PHASE3)
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| ClinicalTrials.gov | Trial enrolment, design, endpoints, results |
Competitive intelligence
For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:
- Tamoxifen (open label) CI brief — competitive landscape report
- Tamoxifen (open label) updates RSS · CI watch RSS
- Oregon Health and Science University portfolio CI