Clinical Trials

Multiple clinical trials, encompassing Phase 2 and Phase 3 investigations, have evaluated 4-hydroxytamoxifen for treating estrogen receptor-positive breast cancer, ductal carcinoma in situ, mammographic breast density, and cyclic mastalgia. Sponsored by academic institutions and industry entities, these studies encompass completed, terminated, and active protocols assessing topical and transdermal formulations against oral tamoxifen. Overall, these trials reflect a focused effort to evaluate localized transdermal delivery for mitigating benign and malignant breast pathologies while minimizing systemic toxicity.

NCT Number Recruitment Conditions Sponsor/Collaborators Start Date Phases
NCT04009044 ACTIVE_NOT_RECRUITING
Cancer Survivor; Ductal Breast Carcinoma In Situ; Invasive Breast Carcinoma
Northwestern University
 2020-02-17 PHASE2
NCT04570956 TERMINATED
Breast Atypical Hyperplasia; Breast Lobular Carcinoma in Situ; Breast Atypical Lobular Hyperplasia; Breast Carcinoma
Mayo Clinic
 2021-07-26 PHASE2
NCT05133674 Unknown status
Breast Cancer|Breast Carcinoma|Breast Tumors|Cancer of Breast|Malignant Neoplasm of Breast
Karolinska University Hospital
 2022-04-04 Phase 2
NCT03063619 COMPLETED
Mammographically Dense Breast
M.D. Anderson Cancer Center
 2018-01-30 PHASE2
NCT02993159 COMPLETED
Ductal Breast Carcinoma In Situ; Estrogen Receptor Positive
Northwestern University
 2017-05-31 PHASE2
NCT03199963 TERMINATED
Mammographic Breast Density
BHR Pharma, LLC
 2017-08-21 PHASE3
NCT00952731 COMPLETED
Ductal Breast Carcinoma in Situ; Estrogen Receptor-positive Breast Cancer
Northwestern University
 2009-12 PHASE2
NCT00084344 COMPLETED
Breast Cancer
Northwestern University
 2003-04
NCT00272714 COMPLETED
Cyclic Breast Pain, Cyclic Mastalgia
ASCEND Therapeutics
 2003-03 PHASE2

(data from https://clinicaltrials.gov, updated on 2025-10-09)

Check the 4-Hydroxytamoxifen (Afimoxifene) product page for in-depth specifications, including solubility, stock solutions, MOA, and working concentrations.

Compliance for Clinical Use

Mechanism and Biochemical Profile

4-Hydroxytamoxifen acts as a selective estrogen receptor modulator that directly binds to the estrogen receptor, competitively inhibiting estrogen binding and blocking downstream receptor dimerization and transcriptional activity. This inhibition arrests estrogen-dependent cell cycle progression and suppresses cellular proliferation, providing therapeutic efficacy against estrogen receptor-positive breast cancer, ductal carcinoma in situ, and related breast pathologies studied in clinical trials.

Appendix RUO and cGMP Quality Standards

Quality Dimension RUO (Research Use Only) cGMP (Current Good Manufacturing Practice)
Clinical Applicability Prohibited in human clinical trials or medical diagnostics. Mandatory for human clinical trials (Phase I–III) and therapies.
Regulatory Status Non-regulated grade; exempt from drug manufacturing laws. Legally enforced by health authorities (e.g., FDA, EMA, NMPA).
Facility Environment Unclassified analytical or research laboratories. Validated Cleanrooms (ISO Class 5–8) with continuous monitoring.
Quality Control Basic purity and activity testing. Rigorous safety release testing (Sterility, Endotoxin, Mycoplasma).
Process Validation Basic equipment calibration; no process validation required. Full qualification (IQ/OQ/PQ) and complete batch records.
Quality Assurance Vendor self-declared without required formal QMS. Mandatory QA/QC unit, Change Control, CAPA, and vendor audits.
Regulatory Impact High risk of IND rejection if used as a critical raw material. Required for IND/NDA filings, supported by Drug Master Files (DMF).

Footnotes

Regulatory Note: Governed by FDA (21 CFR Parts 210/211/312), EMA (EudraLex Vol 4), ICH Guidelines (E6/Q7/Q9/Q10), and compendial standards (USP <71>/<85>/<1043>).

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Note: Technical data last updated: Sep 1, 2026.