Phase I Trial of Endoxifen Gel Versus Placebo in Women Undergoing Breast Surgery
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ClinicalTrials.gov Identifier: NCT03317405 |
Recruitment Status :
Active, not recruiting
First Posted : October 23, 2017
Last Update Posted : March 9, 2022
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Condition or disease | Intervention/treatment | Phase |
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Breast Ductal Carcinoma In Situ Breast Lobular Carcinoma In Situ Stage 0 Breast Cancer AJCC v6 and v7 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 | Drug: Endoxifen Hydrochloride Other: Placebo Administration Other: Questionnaire Administration | Phase 1 |
PRIMARY OBJECTIVE:
I. To establish the dermal tolerability and safety of endoxifen hydrochloride (endoxifen [ENX]) gel administered topically to both breasts at two doses: 10 mg daily (5 mg per breast) and 20 mg daily (10 mg per breast) in comparison to vehicle placebo gel, using objective assessments based on Common Terminology Criteria for Adverse Events (CTCAE) criteria.
SECONDARY OBJECTIVES:
I. To measure the breast tissue concentrations of (E) and (Z) isomers of N-desmethyl-4-hydroxytamoxifen (ENX) and 4-hydroxytamoxifen (4-OHT) at each dose (10 mg per day and 20 mg per day).
II. To measure the plasma concentrations of (E) and (Z) isomers ENX and 4-OHT at each dose (10 mg per day and 20 mg per day).
III. To measure serum estrogenic response to topical ENX gel therapy in comparison to vehicle placebo gel (sex hormone binding globulin and insulin-like growth factor [IGF] pathway proteins).
IV. To assess changes in coagulation parameters (factor VIII, factor IX, vWF, protein S) in response to ENX gel therapy in comparison to vehicle placebo gel.
V. To assess symptoms related to use of endoxifen gel in comparison to vehicle placebo gel, as assessed by the Breast Cancer Prevention Trial (BCPT) Eight Symptom Scale (BESS) questionnaire.
EXPLORATORY OBJECTIVE:
I. Using pathological lesion-matched pre- and post-therapy tissue samples, to explore the potential therapeutic effects of the two doses of ENX gel in comparison to vehicle placebo gel: a) by IHC, Ki67 labelling (for cell proliferation), estrogen receptor (ER), progesterone receptor (PR) expression (for estrogen blockade); b) by expression of a panel of genes reported to change with ENX exposure (using nanostring assays).
OUTLINE: Participants are randomized in Cohorts 1 and 2. All subjects in Cohort 3 will receive active agent.
COHORT I: Participants apply endoxifen hydrochloride gel to both breast skin and keep it untouched over at least 4 hours once daily for 21-28 days before breast surgery.
COHORT II: Participants apply placebo to both breast skin and keep it untouched over at least 4 hours once daily for 21-28 days before breast surgery.
COHORT III: Participants apply endoxifen hydrochloride gel to both breast skin and keep it untouched over at least 4 hours once daily for 21-28 days before breast surgery.
After completion of study treatment, participants are followed up at 60 days.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 33 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Triple (Participant, Investigator, Outcomes Assessor) |
Primary Purpose: | Prevention |
Official Title: | Phase I Trial of Endoxifen Gel Versus Placebo Gel in Women Undergoing Breast Surgery |
Actual Study Start Date : | October 31, 2018 |
Actual Primary Completion Date : | February 22, 2021 |
Estimated Study Completion Date : | February 22, 2023 |

Arm | Intervention/treatment |
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Experimental: Cohort I (endoxifen hydrochloride)
Participants apply endoxifen hydrochloride gel to both breast skin and keep it untouched over at least 4 hours once daily for 21-28 days before breast surgery.
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Drug: Endoxifen Hydrochloride
Apply to the skin
Other Names:
Other: Questionnaire Administration Ancillary studies |
Placebo Comparator: Cohort II (placebo)
Participants apply placebo to both breast skin and keep it untouched over at least 4 hours once daily for 21-28 days before breast surgery.
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Other: Placebo Administration
Apply to the skin Other: Questionnaire Administration Ancillary studies |
- Incidence of skin toxicity [ Time Frame: Up to 60 days ]Will be assessed by Common Terminology Criteria for Adverse Events version 4.
- Drug concentration [ Time Frame: Up to 60 days ]Will be assessed in breast tissue and blood.
- Breast tissue biomarkers [ Time Frame: Up to 60 days ]Ki67 labeling index, progesterone receptor and estrogen receptor expression, and expression of a panel of genes reported to change with Z-endoxifen hydrochloride (ENX) exposure, will be measured in breast tissue samples obtained at diagnostic core needle biopsy performed prior to study entry, and compared to the measurements in post-therapy surgical samples.
- Coagulation proteins [ Time Frame: Up to 60 days ]Will assess coagulation proteins measures of systemic estrogenicity in plasma.
- Treatment related symptoms [ Time Frame: Up to 60 days ]Assessed using the Behavioral and Emotional Screening System questionnaire. Average, median and range of scores for each noted group will be provided as descriptive measures of location and variance.
- Tissue biologic response [ Time Frame: Up to 60 days ]Will be compared as pre- and post-therapy values, to explore the potential therapeutic effects of the two doses of ENX. A nonparametric test of the central parameter being zero will be performed.

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | Female |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Women scheduled for unilateral or bilateral mastectomy for breast cancer therapy, pathology confirmed stage 0-III (including ductal carcinoma in situ), or prophylaxis (BRCA1/2 mutation carriers, women with strong family history or lobular carcinoma in situ or other conditions where prophylactic mastectomy has been elected)
- Age >= 18 years (since breast cancer is not a pediatric disease and no safety data are available for ENX use in children)
- Eastern Cooperative Oncology Group (ECOG) performance status =< 1 (Karnofsky >= 70%)
- Total bilirubin < 1.5 x upper limit of normal (ULN) (in women with prior documented bilirubin elevations consistent with Gilbert's syndrome, total bilirubin up to 3 x ULN will be allowed)
- Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase [SGOT]) < 2.5 x ULN
- Alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) < 2.5 x ULN
- Creatinine < 2 x ULN
- Alkaline phosphatase < 2.5 x ULN
- Blood urea nitrogen < 2 x ULN
- Ability to understand and the willingness to sign a written informed consent document which includes a requirement to apply study agent to sensitive body parts daily
- Willingness and ability to schedule mastectomy 21-28 days following start of study agent; women with breast implants may participate
- Willingness to avoid exposing breast skin to natural or artificial sunlight (i.e. tanning beds) for the duration of study agent dosing
- Negative urine or serum pregnancy test result, for participants of child bearing potential; female of child-bearing potential is any woman (regardless of sexual orientation, whether she has undergone a tubal ligation, or remains celibate by choice) who meets the following criteria: has not undergone a hysterectomy or bilateral oophorectomy; AND has had a menstrual period at any time in the preceding 12 consecutive months)
- The effects of topical ENX gel on the developing human fetus are unknown; for this reason, women of child-bearing potential and their male partners must agree to use effective forms of birth control (abstinence is not an allowed method) prior to study entry and for the duration of study participation; should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her study physician immediately
Exclusion Criteria:
- The presence of gross skin invasion/ulceration by the breast cancer, or inflammatory changes with skin edema AND erythema; Note: Paget's disease is permitted
- Women receiving a "nipple delay" procedure prior to mastectomy
- Women with skin diseases (psoriasis, eczema)
- A history of thromboembolic disorder
- Endometrial intraepithelial neoplasia (also known as atypical hyperplasia) or a high risk of uterine cancer, defined here as known carriers of Lynch syndrome mutations (MLH1, MSH2, MSH6, PMS2)
- Participants may not have received any other investigational agents in the previous 3 months
- History of allergic reactions attributed to compounds of similar chemical or biologic composition to tamoxifen
- Taken tamoxifen or other selective estrogen/progesterone receptor modulators (SERMs/SPRMs) within two years prior to entering study or been required to discontinue SERM therapy due to thromboembolic or uterine toxicity
- Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements
- History of prior breast cancer-specific therapy within the previous 2 years (chemotherapy, radiation, anti-HER2 agents, endocrine agents, everolimus, CDK4-6 inhibitors); previous unilateral radiation of the contralateral side in women scheduled for mastectomy is allowed; study gel will be applied to both breasts
- History of prior mastectomy
- Pregnant or breastfeeding
- Patients receiving neoadjuvant chemotherapy with curative intent
- Men are excluded from this study since breast cancer is men is rare and there are no data regarding skin penetration of topical breast cancer prevention agents through male chest wall skin (which is thicker and harrier than female chest wall skin)
- Current users of other topical medications on the breast skin must be willing and able to discontinue use for the duration of participation; body lotion and other non-medicinal topical compounds may be applied > 4 hours after study gel application

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03317405
United States, California | |
Cedars Sinai Medical Center | |
Los Angeles, California, United States, 90048 | |
United States, Illinois | |
Northwestern University | |
Chicago, Illinois, United States, 60611 | |
United States, New York | |
Memorial Sloan Kettering Cancer Center | |
New York, New York, United States, 10065 |
Principal Investigator: | Seema A Khan | Northwestern University |
Documents provided by National Cancer Institute (NCI):
Responsible Party: | National Cancer Institute (NCI) |
ClinicalTrials.gov Identifier: | NCT03317405 |
Other Study ID Numbers: |
NCI-2017-01921 NCI-2017-01921 ( Registry Identifier: CTRP (Clinical Trial Reporting Program) ) N01-CN-2012-00035 NCI2017-09-01 ( Other Identifier: Northwestern University ) NWU2017-09-01 ( Other Identifier: DCP ) N01CN00035 ( U.S. NIH Grant/Contract ) P30CA060553 ( U.S. NIH Grant/Contract ) |
First Posted: | October 23, 2017 Key Record Dates |
Last Update Posted: | March 9, 2022 |
Last Verified: | February 2022 |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Carcinoma Breast Neoplasms Carcinoma in Situ Carcinoma, Ductal Carcinoma, Intraductal, Noninfiltrating Breast Carcinoma In Situ Carcinoma, Lobular Carcinoma, Ductal, Breast Neoplasms, Glandular and Epithelial Neoplasms by Histologic Type Neoplasms Neoplasms by Site Breast Diseases |
Skin Diseases Adenocarcinoma Neoplasms, Ductal, Lobular, and Medullary Tamoxifen Estrogen Antagonists Hormone Antagonists Hormones, Hormone Substitutes, and Hormone Antagonists Physiological Effects of Drugs Antineoplastic Agents, Hormonal Antineoplastic Agents Selective Estrogen Receptor Modulators Estrogen Receptor Modulators Bone Density Conservation Agents |