Tamoxifen
As of the edition of 20 October 2026, Tamoxifen is a small molecule: marketed, first approved in 1982 (US); acts on ESR1; no US protection is listed.
Sources: FDA Orange Book and Purple Book, other approval registers, ClinicalTrials.gov, ChEMBL.
The drug
- Status
- Marketed; latest approval 1989
- Kind
- Small molecule
- Brand name
- Nolvadex
- First approved
- 1 January 1982 (US)
- Approvals on record
- 6 in 4 regions
- Holder of the most recent approval
- Mayne Pharma Commercial; 5 holders in all
- Registered trials
- 301, 28 stopped early
- Disease areas
- Cancer; Skin and connective tissue; Urinary and reproductive; Nervous system; Pregnancy and women's health; Hormones
US protection
No US protection is listed.
The FDA registers list no drug-substance patent or exclusivity that counts for this drug.
This is the US only.
Target
| Gene | Protein | UniProt |
|---|---|---|
| ESR1 | Estrogen receptor | P03372 |
Registered trials
| Phase | Trials | Completed | Active | Stopped early |
|---|---|---|---|---|
| Phase not stated | 32 | 13 | 2 | 2 |
| Phase 1 | 28 | 16 | 6 | 3 |
| Phase 2 | 136 | 70 | 33 | 16 |
| Phase 3 | 91 | 49 | 16 | 6 |
| Phase 4 | 14 | 9 | 1 | 1 |
| All trials | 301 |
Who has held its approvals
| Company | Role | Years |
|---|---|---|
| Orion Pharma | Applicant | 1987 to now |
| AstraZeneca | Applicant and Lead sponsor of trials | 1994 to now |
| Savient Pharmaceuticals | Later holder | 2005 to now |
| Mayne Pharma Commercial | Acquired holder | 2023 to now |
| Stuart Therapeutics | Earlier holder |