Clinical Trials

Numerous clinical trials evaluate Endoxifen HCl across diverse therapeutic indications, primarily focusing on estrogen receptor-positive, HER2-negative, and invasive breast cancers, mammographic breast density, and non-oncologic conditions such as bipolar I disorder. Spanning Phase 1 through Phase 3—including neoadjuvant Phase 2 evaluations and early-phase dose-optimization studies—these trials are sponsored by pharmaceutical companies like Atossa Therapeutics and Jina Pharmaceuticals alongside academic institutions such as Karolinska University Hospital. The recruitment statuses across these protocols include active recruitment, completed studies, and active, non-recruiting trials.

NCT Number Recruitment Conditions Sponsor/Collaborators Start Date Phases
NCT01042379 RECRUITING
Breast Neoplasms; Breast Cancer; Breast Tumors; Angiosarcoma; TNBC - Triple-Negative Breast Cancer; HER2-positive Breast Cancer; HER2-negative Breast Cancer; Hormone Receptor Positive Tumor; Hormone Receptor Negative Tumor; Early-stage Breast Cancer; Locally Advanced Breast Cancer
QuantumLeap Healthcare Collaborative
 2010-03-01 PHASE2
NCT06075953 RECRUITING
Ductal Carcinoma in Situ
QuantumLeap Healthcare Collaborative
 2024-02-17 PHASE2
NCT05607004 ACTIVE_NOT_RECRUITING
Breast Neoplasms; Invasive Breast Cancer; Estrogen-receptor-positive Breast Cancer; HER2-negative Breast Cancer
Atossa Therapeutics, Inc.
 2023-02-14 PHASE2
NCT06608641 ACTIVE_NOT_RECRUITING
Bipolar 1 Disorder
Jina Pharmaceuticals Inc.
 2024-03-19 PHASE3
NCT05068388 COMPLETED
Breast Density
Atossa Therapeutics, Inc.
 2021-12-21 PHASE2
NCT05607004 Recruiting
Breast Neoplasms|Invasive Breast Cancer|Estrogen-receptor-positive Breast Cancer|HER2-negative Breast Cancer
Atossa Therapeutics Inc.|InClin
 2023-02-14 Phase 2
NCT05133674 Unknown status
Breast Cancer|Breast Carcinoma|Breast Tumors|Cancer of Breast|Malignant Neoplasm of Breast
Karolinska University Hospital
 2022-04-04 Phase 2
NCT03931928 COMPLETED
Breast Cancer; DCIS
Robert Bosch Gesellschaft für Medizinische Forschung mbH (RBMF)
 2019-09-10 PHASE2
NCT03317405 ACTIVE_NOT_RECRUITING
Breast Carcinoma In Situ; Breast Ductal Carcinoma In Situ; Breast Lobular Carcinoma In Situ; Stage I Breast Cancer AJCC v7; Stage IA Breast Cancer AJCC v7; Stage IB Breast Cancer AJCC v7; Stage II Breast Cancer AJCC v6 and v7; Stage IIA Breast Cancer AJCC v6 and v7; Stage IIB Breast Cancer AJCC v6 and v7; Stage III Breast Cancer AJCC v7; Stage IIIA Breast Cancer AJCC v7; Stage IIIB Breast Cancer AJCC v7; Stage IIIC Breast Cancer AJCC v7
National Cancer Institute (NCI)
 2018-10-31 PHASE1
NCT04315792 COMPLETED
Bipolar I Disorder
Jina Pharmaceuticals Inc.
 2020-08-03 PHASE3
NCT04961632 Active not recruiting
Breast Cancer
National Cancer Centre Singapore|National Medical Research Council (NMRC) Singapore
 2020-12-23 Phase 1
NCT02311933 ACTIVE_NOT_RECRUITING
Recurrent Breast Carcinoma; Stage III Breast Cancer AJCC v7; Stage IIIA Breast Cancer AJCC v7; Stage IIIB Breast Cancer AJCC v7; Stage IIIC Breast Cancer AJCC v7; Stage IV Breast Cancer AJCC v6 and v7
National Cancer Institute (NCI)
 2015-05-28 PHASE2
NCT01273168 COMPLETED
Hormone Receptor-Positive Breast; Gynecologic; Desmoid; Hormone Receptor-Positive Neoplasms
National Cancer Institute (NCI)
 2011-03-01 PHASE1
NCT04315792 Recruiting
Bipolar I Disorder
Jina Pharmaceuticals Inc.|Novum Pharmaceutical Research Services|Lambda Therapeutic Research Ltd.|Intas Pharmaceuticals Ltd.
 2020-03-23 Phase 3
NCT04312347 Completed
ER+ Breast Cancer
Nalagenetics Pte Ltd
 2019-09-06 Not Applicable
NCT04616430 COMPLETED
Mammographic Breast Density
Atossa Therapeutics, Inc.
 2018-04-09 PHASE2
NCT01327781 ACTIVE_NOT_RECRUITING
HER2/Neu Positive; Recurrent Breast Carcinoma; Stage IIIC Breast Cancer AJCC v7; Stage IV Breast Cancer AJCC v6 and v7
National Cancer Institute (NCI)
 2011-03-25 PHASE1

(data from https://clinicaltrials.gov, updated on 2026-05-06)

Check the Endoxifen HCl product page for in-depth specifications, including solubility, stock solutions, MOA, and working concentrations.

Compliance for Clinical Use

Mechanism and Biochemical Profile

Endoxifen HCl functions as a potent active metabolite of tamoxifen that selectively binds to estrogen receptors, thereby blocking downstream estrogen-dependent transcriptional activation and proliferative signaling pathways. By suppressing estrogen-driven cell growth and survival, this potent receptor antagonism directly inhibits tumor progression in clinical settings such as estrogen receptor-positive breast cancer and reduced mammographic breast density.

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.