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ER Reactivation Therapy for Breast Cancer

NCT02188745 · Status: COMPLETED · Phase: PHASE2 · Type: INTERVENTIONAL · Enrollment: 19

Last updated 2024-07-17

No results posted yet for this study

Summary

Before anti-estrogens such as tamoxifen were developed to treat estrogen receptor (ER)-positive breast cancer, high-dose estrogen therapies were used. This seems counterintuitive since anti-estrogens block ER function, while estrogens increase ER function, but these therapies are effective to similar extents for the treatment of metastatic ER+ breast cancer. Estrogen therapies are most effective against cancers that develop resistance to anti-estrogens, likely because such cancers have adapted to grow without ER function, and restoring ER function (with estrogen) is damaging to the cancer cells. In some patients with ER+ breast cancer that becomes resistant to anti-estrogens, treatment with the estrogen 17B-estradiol induces tumor response. Furthermore, when 17B-estradiol-sensitive tumors eventually become resistant to 17B-estradiol, switching back to anti-estrogen therapy is often effective. These observations suggest that cancers can alternate between anti-estrogen-sensitive and 17B-estradiol-sensitive states. The investigators hypothesize that treatment with alternating 17B-estradiol / anti-estrogen therapies on a defined 8-week / 16-week schedule will more effectively prevent cancer growth than continuous treatment with either type of therapy in patients with metastatic anti-estrogen-resistant ER+ breast cancer.

Conditions

Interventions

DRUG

17B-estradiol

Anti-estrogen

DRUG

Letrozole

Aromatase inhibitors work by blocking estrogen receptors; they stop a key enzyme (called aromatase) from changing other hormones into estrogen. This lowers estrogen levels in the body, taking away the fuel that estrogen receptor-positive breast cancers need to grow.

DRUG

Anastrozole

Aromatase inhibitors work differently from tamoxifen and raloxifene. Instead of blocking the estrogen receptors, they stop a key enzyme (called aromatase) from changing other hormones into estrogen. This lowers estrogen levels in the body, taking away the fuel that estrogen receptor-positive breast cancers need to grow.

DRUG

Exemestane

Aromatase inhibitors work differently from tamoxifen and raloxifene. Instead of blocking the estrogen receptors, they stop a key enzyme (called aromatase) from changing other hormones into estrogen. This lowers estrogen levels in the body, taking away the fuel that estrogen receptor-positive breast cancers need to grow.

Sponsors & Collaborators

  • Dartmouth-Hitchcock Medical Center

    lead OTHER

Principal Investigators

  • Mary Chamberlin, MD · Dartmouth-Hitchcock Medical Center

Study Design

Allocation
NA
Purpose
TREATMENT
Masking
NONE
Model
SINGLE_GROUP

Eligibility

Min Age
18 Years
Sex
FEMALE
Healthy Volunteers
No

Timeline & Regulatory

Start
2016-03-11
Primary Completion
2024-01-05
Completion
2024-07-05

Countries

  • United States

Study Locations

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Entities

Drugs
Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT02188745 on ClinicalTrials.gov