Tamoxifen clinical trials
Tamoxifen is named as an intervention in 38 current clinical trials in our Spain, Italy, USA, France, Canada, Mexico, Germany, Israel, China, Belgium, Taiwan, Brazil, Ireland, Netherlands, Portugal, UK, Turkey, South Korea, Japan, India, Poland, Australia, Singapore, Czechia, Sweden, Austria, Switzerland and Denmark registers. 16 are recruiting patients now. The most common phase is Phase 3. The sponsor with the most trials is Eli Lilly and Company (4). The most-studied condition is Breast Cancer. The EU clinical trials register (CTIS) separately lists 3 authorised or ongoing trials, 1 with a site in Ireland.
Where Tamoxifen is approved
All regulators →Of the three regulators tracked here, the first to approve Tamoxifen was the US, on 30 Dec 1977.
- 3 EU orphan designations, most recently for treatment of Duchenne muscular dystrophy (12 Oct 2017, positive)
From the regulators' own registers: FDA Drugs@FDA, the EMA medicines list and Health Canada's Notice of Compliance database. Dates are the first listed approval of a product containing only this substance; combination products and nationally authorised EU medicines are not counted.
What health systems spend on Tamoxifen
All medicines →From NHSBSA Prescription Cost Analysis (Open Government Licence v3.0) and CMS State Drug Utilization Data. Both are gross amounts: neither system publishes its discounts or rebates per drug. Products combining several substances are not counted here.
How Tamoxifen works
All drug targets →- Estrogen receptor alpha modulator ModulatorTarget: ESR1 estrogen receptor 1✓ In ChEMBL and the Guide to Pharmacology
- Duchenne muscular dystrophyPhase 3
- Bipolar disorderPhase 3
- Breast adenocarcinomaPhase 3
- Breast carcinomaPhase 3
- Ductal breast carcinoma in situPhase 3
- Estrogen-receptor negative breast cancerPhase 3
- Estrogen-receptor positive breast cancerPhase 3
- Hepatocellular carcinomaPhase 3
- Invasive ductal breast carcinomaPhase 3
- Liver cancerPhase 3
Mechanisms and diseases from ChEMBL via the Open Targets Platform (release 26.09), ChEMBL record CHEMBL83, CC BY-SA 3.0. Targets checked against the IUPHAR/BPS Guide to PHARMACOLOGY (2026.3.1), ligand 1016, CC BY-SA 4.0. Trial phases are not approvals: approved uses are shown from the regulators' own records where we hold them.
Patient leaflets for Tamoxifen
The package leaflet is the official guide for patients that comes with every medicine. These links go to the regulators that publish it.
- IEIreland: 3 products on the HPRA listEach product record links to the HPRA, which publishes the leaflet and SmPC.
- UKUnited Kingdom: Search MHRA ProductsPatient information leaflets and SmPCs for UK-licensed products.
- USUnited States: Search DailyMedFDA-approved labels, including patient and medication guides.
Leaflets differ between brands and countries; always read the one that comes with your own medicine. This is regulatory information, not medical advice.
Reference identifiers for Tamoxifen
- ATC code
- L02BA01
- ChEMBL
- CHEMBL83
- DrugBank
- DB00675
- PubChem CID
- 2733526
- CAS number
- 10540-29-1
- FDA UNII
- 094ZI81Y45
- Wikidata
- Q412178
- Wikipedia
- Tamoxifen
Codes that identify this medicine in other databases, from Wikidata (CC0), matched by its ChEMBL ID. The ATC code is the WHO classification of what the medicine is used for.
Trials by status
Trials by phase
Clinical trials of Tamoxifen
38 trialsRegisters list studies that are recruiting, about to open, active but closed to enrolment, or enrolling by invitation. The UK and USA registers cover industry-sponsored studies only. Trial titles and statuses are copied from the registry as published.
Tamoxifen in the EU trials register (CTIS)
3 trials · 1 in IrelandAuthorised or ongoing trials in the EU Clinical Trials Information System that list a product containing Tamoxifen. Many trials are registered in both CTIS and ClinicalTrials.gov, so these are shown separately rather than added to the count above. Trials with a site in Ireland are listed first.
| Study | Phase | Status | Sponsor | Countries |
|---|---|---|---|---|
|
J2J-MC-JZLL - preEMBER: A Phase 2, Open-label Study Evaluating Imlunestrant in Premenopausal Women with Estrogen Receptor-Positive, HER2-Negative Breast Cancer.
2025-523258-15-00 · Neoplasms
|
Phase 2 | Ongoing | Eli Lilly & Co | Ireland + 4 more |
|
NoELA_No Endocrine therapy in small HR+ HER2- low relapse risk Luminal A early breast cancer, a single-arm de-escalation trial
2025-523683-20-00 · CTIS ↗ · Neoplasms
|
Phase 2 | Authorised | Unicancer | France |
|
ENDO-67 project: Investigating ENDOcrine therapy-related questions using Ki67 changes in the window-of-opportunity before breast surgery
2025-521385-10-00 · CTIS ↗ · Neoplasms
|
Phase 4 | Authorised | Erasmus Universitair Medisch Centrum Rotterdam (Erasmus MC) | Netherlands |
Tamoxifen across our data
Ireland · EU · USThe same active substance in our other registers, matched by its exact name. Each entry links to the register record it comes from.
Licensed in Ireland (HPRA)
3 single-substance products containing Tamoxifen on the HPRA medicines list.
- Tamox 10 mg Film-coated tabletsRowex Limited, · PA0711/022/001 · Marketed
- Tamox 20 mg film-coated tabletsRowex Limited, · PA0711/022/002 · Marketed
- Tamoxifen 20 mg tabletsViatris Limited · PA23266/052/001 · Marketed
Supply shortages
No entry for Tamoxifen in the EMA, FDA or German BfArM shortage lists we track.
Conditions studied with Tamoxifen
53 conditionsAll 53 conditions
| Condition (as registered) | Trials |
|---|---|
| Breast Cancer | 13 |
| Breast Neoplasms | 4 |
| HER2-negative Breast Cancer | 3 |
| Breast Cancer, Early Breast Cancer | 2 |
| Hormone Receptor Positive Tumor | 2 |
| Early-Stage Breast Carcinoma | 2 |
| Solid Tumors, Adult | 1 |
| ER-positive Breast Cancer | 1 |
| Stage IIB Breast Cancer | 1 |
| Stage III Breast Cancer | 1 |
| Malignant Neoplasm | 1 |
| Estrogen Receptor (ER)-Positive, HER2-negative, Locally Advanced or Metastatic Breast Cancer | 1 |
| Hot Flashes | 1 |
| Metastatic Breast Cancer | 1 |
| Ductal Carcinoma In Situ, DCIS | 1 |
| Pancreatic Neoplasms | 1 |
| Ductal Carcinoma in Situ | 1 |
| Extensive Disease | 1 |
| Mastectomy | 1 |
| ER+ Breast Cancer | 1 |
| Premenopausal Breast Cancer | 1 |
| Carcinoma, Intraductal, Noninfiltrating | 1 |
| Recurrence, Local Neoplasm | 1 |
| Atypical Hyperplasia | 1 |
| Endometrial Cancer Stage III | 1 |
| Endometrial Cancer Stage IV | 1 |
| Endometrial Cancer Recurrent | 1 |
| Estrogen Receptor Positive Tumor | 1 |
| CNS Embryonal Tumor | 1 |
| CNS, Medulloblastoma | 1 |
| Atypical Teratoid Rhabdoid Tumor | 1 |
| Medulloblastoma, Childhood | 1 |
| Hypogonadism | 1 |
| Prostate Cancer | 1 |
| Glioblastoma Multiforme | 1 |
| Ovarian Cancer | 1 |
| Early-stage Breast Cancer | 1 |
| High Risk Breast Carcinoma | 1 |
| HER2-positive Breast Cancer | 1 |
| Invasive Carcinoma of the Breast | 1 |
| Node Negative Breast Cancer | 1 |
| Breast Ductal Carcinoma In Situ | 1 |
| Invasive Breast Carcinoma | 1 |
| Multicentric Breast Carcinoma | 1 |
| Multifocal Breast Carcinoma | 1 |
| Breast Adenocarcinoma | 1 |
| Hormone Receptor Positive | 1 |
| Stage IA Breast Cancer AJCC v7 | 1 |
| Stage IB Breast Cancer AJCC v7 | 1 |
| Recurrent Breast Carcinoma | 1 |
| Stage III Breast Cancer AJCC v7 | 1 |
| Stage IIIA Breast Cancer AJCC v7 | 1 |
| Stage IIIB Breast Cancer AJCC v7 | 1 |
Sponsors
lead sponsor per trial+ 10 more sponsors in the trial list above.
By country register
A trial with sites in more than one country appears in each of those registers. CTIS does not publish a recruiting flag; its trials may also appear in the registers above.
Related compounds
Questions about Tamoxifen trials
How many clinical trials are testing Tamoxifen?
38 current trials in our Spain, Italy, USA, France, Canada, Mexico, Germany, Israel, China, Belgium, Taiwan, Brazil, Ireland, Netherlands, Portugal, UK, Turkey, South Korea, Japan, India, Poland, Australia, Singapore, Czechia, Sweden, Austria, Switzerland and Denmark registers name Tamoxifen as a drug or biological intervention, as of the registry sync on 10 November 2026. Completed and withdrawn studies are not counted.
Are Tamoxifen trials recruiting patients?
Yes. 16 of the 38 trials are recruiting: 5 with sites in Spain, 5 with sites in Italy, 4 with sites in USA, 6 with sites in France, 5 with sites in Canada, 1 with sites in Mexico, 4 with sites in Germany, 1 with sites in Israel, 5 with sites in China, 4 with sites in Belgium, 3 with sites in Taiwan, 2 with sites in Brazil, 3 with sites in Ireland, 4 with sites in Netherlands, 2 with sites in Portugal, 2 with sites in UK, 2 with sites in Turkey, 1 with sites in South Korea, 2 with sites in Japan, 1 with sites in India, 1 with sites in Poland, 1 with sites in Australia, 2 with sites in Singapore, 1 with sites in Czechia, 1 with sites in Sweden, 1 with sites in Austria and 1 with sites in Switzerland. Eligibility and site contacts are on each trial's record. Only the study team can confirm whether a patient is eligible.
Who sponsors Tamoxifen clinical trials?
Eli Lilly and Company (4), Fudan University (3), Dana-Farber Cancer Institute (3) and National Cancer Institute (NCI) (3), among 25 lead sponsors in total. The number in brackets is how many trials each organisation leads.
Are there Tamoxifen clinical trials in Ireland?
Yes. 7 trials in our Ireland register (ClinicalTrials.gov), and 1 trial in the EU register (CTIS) list a site in Ireland. Some may be the same study registered in both. See the Irish clinical trials register for sites and contacts.
Is Tamoxifen licensed in Ireland?
Yes. The HPRA medicines list includes 3 single-substance products containing Tamoxifen, for example Tamox 10 mg Film-coated tablets (Rowex Limited,). A licence does not mean a product is currently marketed or reimbursed; see each product's record.
Is there a Tamoxifen shortage?
Not in the lists we track: Tamoxifen has no entry in the EMA, FDA or German BfArM shortage registers as of their latest sync.
Where does this information come from?
Every trial, status, phase and sponsor on this page is copied from public ClinicalTrials.gov records by a daily sync. Nothing here describes how Tamoxifen works or whether it is effective, and it is not medical advice.
How this page is built
Everything on this page is copied from public ClinicalTrials.gov registry records — it is not written from memory, and nothing here describes how Tamoxifen works or whether it is effective. Each trial links to its own record so you can check it yourself.
- ClinicalTrials.gov (U.S. National Library of Medicine) ↗ Trial IDs, titles, intervention names and synonyms, phase, overall status, lead sponsor and conditions for every trial on this page
This page is built automatically: a daily sync job reads the registry records behind our country trial registers, collects every trial that lists Tamoxifen (or a registered synonym) as a drug or biological intervention, and tabulates the registry fields directly. Placebos and generic comparators are excluded. There is no AI drafting and no per-compound editorial pass, and the page has not been clinically reviewed. The “last verified” date above is the timestamp of that sync, not a review date. Our general editorial approach is described in our editorial standards and corrections policy. The ClinicalTrials.gov data on this page was last retrieved on 10 Nov 2026. How every register is built: methodology · fixes we have made: corrections log.