What side effects are associated with this type of intervention?

Aromatase inhibitors like Letrozole, used in the treatment of hormone receptor-positive breast cancer, commonly cause side effects such as loss of bone density, increased risk of fractures, and cardiovascular risks. Other frequent side effects include joint pain, hot flashes, and fatigue. Patients should discuss these potential side effects with their healthcare provider to manage and mitigate risks effectively.

What other types of research exist?

Promising novel alternatives to Letrozole for breast cancer patients in 2024 include other aromatase inhibitors like anastrozole and exemestane, as well as selective estrogen receptor modulators (SERMs) such as tamoxifen. Additionally, novel hormonal therapies like selective estrogen receptor degraders (SERDs) and CDK4/6 inhibitors (e.g., palbociclib, ribociclib) are showing promise in clinical trials for hormone receptor-positive breast cancer.

← Back to Search

Aromatase Inhibitor

Letrozole for Breast Cancer

Q: What is the mechanism of action of this treatment?

The most common treatments for hormone receptor-positive breast cancer include endocrine therapies like aromatase inhibitors (e.g., Letrozole) and selective estrogen receptor modulators (SERMs) like tamoxifen. Letrozole works by inhibiting the enzyme aromatase, which is responsible for converting androgens into estrogen, thereby reducing estrogen levels in the body and slowing the growth of estrogen-dependent cancer cells. Tamoxifen, on the other hand, binds to estrogen receptors on cancer cells, blocking estrogen from binding and activating these receptors. These mechanisms are crucial for breast cancer patients because they target the hormonal pathways that fuel the growth of hormone receptor-positive breast cancer, thereby improving treatment outcomes and reducing the risk of recurrence.

Q: What prior FDA approvals exist?

The FDA has approved several aromatase inhibitors for the treatment of hormone receptor-positive breast cancer, similar to letrozole. These include anastrozole and exemestane. These drugs work by inhibiting the enzyme aromatase, which is responsible for converting androgens into estrogen, thereby reducing estrogen levels in the body and slowing the growth of estrogen-dependent breast cancer cells. Letrozole, anastrozole, and exemestane are commonly used in postmenopausal women to treat early and advanced stages of hormone receptor-positive breast cancer.

Phase 2

Waitlist Available

Led By Saranya Chumsri

Research Sponsored by Mayo Clinic

Eligibility Criteria Checklist

Specific guidelines that determine who can or cannot participate in a clinical trial

Must have

Histologically confirmed un-resected operable invasive adenocarcinoma of the breast ≥ 0.5 cm with estrogen receptor (ER) and/or progesterone receptor (PR) positive ≥ 10%, and no human epidermal growth factor receptor 2 (HER2) amplification or overexpression

Willing and able to provide research tissue samples

Must not have

Immunocompromised patients including patients known to be human immunodeficiency virus (HIV) positive or those on chronic steroids

Known history of active autoimmune disease that has required systemic treatment within =< 30 days (i.e., with use of disease modifying agents, corticosteroids, or immunosuppressive drugs) prior to pre-registration

Timeline

Screening 3 weeks

Treatment Varies

Follow Up up to 8 weeks

Awards & highlights

All Individual Drugs Already Approved

Approved for 10 Other Conditions

No Placebo-Only Group

Summary

This trial tests letrozole, a drug that lowers estrogen levels, in patients with a specific type of breast cancer that can be surgically removed. By reducing estrogen, letrozole can help slow or stop the growth of these cancer cells. Letrozole is a highly specific and potent aromatase inhibitor that has been shown to significantly reduce estrogen levels and is used in various breast cancer treatments.

Who is the study for?

This trial is for postmenopausal women over 18 with newly diagnosed, operable breast cancer that's hormone receptor-positive and HER2-negative. Participants must not have had prior treatments for their current breast cancer but may have taken preventive agents like tamoxifen.

What is being tested?

The study tests Letrozole, a medication reducing estrogen to slow or stop the growth of certain breast cancers. It involves collecting biospecimens from patients who can undergo surgery to remove their cancer.

What are the potential side effects?

Letrozole may cause joint pain, hot flashes, weakness, fatigue, increased sweating and cholesterol levels. Rarely it might lead to bone thinning (osteoporosis) or trigger heart problems.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below

Select...

My breast cancer is ER or PR positive, HER2 negative, and can be operated on.

Select...

I am willing to give tissue samples for research.

Select...

I am a woman aged 18 or older.

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:

Select...

I have a weakened immune system, possibly due to HIV or long-term steroid use.

Select...

I have an autoimmune disease treated with medication in the last 30 days.

Timeline

Screening ~ 3 weeks3 visits

Treatment ~ Varies

Follow Up ~ up to 8 weeks

Screening ~ 3 weeks

Treatment ~ Varies

Follow Up ~up to 8 weeks

This trial's timeline: 3 weeks for screening, Varies for treatment, and up to 8 weeks for reporting.

Treatment Details

Study Objectives

Study objectives can provide a clearer picture of what you can expect from a treatment.

Primary study objectives

Differences in tumor microenvironment subpopulations in aromatase inhibitor (AI)-sensitive version (vs.) AI-resistant hormone receptor (HR)+ breast cancer

Secondary study objectives

Effects of estrogen deprivation on the immune microenvironment

Effects of estrogen deprivation on tumor immune microenvironment

Side effects data

From 2018 Phase 4 trial • 79 Patients • NCT02137538

10%

Fracture

Acne

Scoliosis

Hair loss

Sacroiliitis

Neuro event

100%

80%

60%

40%

20%

Study treatment Arm

Anastrozole

Letrozole

Awards & Highlights

All Individual Drugs Already Approved

Therapies where all constituent drugs have already been approved are likely to have better-understood side effect profiles.

Approved for 10 Other Conditions

This treatment demonstrated efficacy for 10 other conditions.

No Placebo-Only Group

All patients enrolled in this study will receive some form of active treatment.

Trial Design

1Treatment groups

Experimental Treatment

Group I: Treatment (letrozole)Experimental Treatment2 Interventions

Patients receive letrozole PO QD for 2-8 weeks prior to surgery in the absence of disease progression or unacceptable toxicity. Patients then undergo collection of blood and tissue samples.

Treatment

First Studied

Drug Approval Stage

How many patients have taken this drug

Biospecimen Collection

2004

Completed Phase 3

~2030

Letrozole

FDA approved

0 / 5Eligibility criteria met

Research Highlights

Information in this section is not a recommendation. We encourage patients to speak with their healthcare team when evaluating any treatment decision.

Mechanism Of Action

Side Effect Profile

Prior Approvals

Other Research

The most common treatments for hormone receptor-positive breast cancer include endocrine therapies like aromatase inhibitors (e.g., Letrozole) and selective estrogen receptor modulators (SERMs) like tamoxifen. Letrozole works by inhibiting the enzyme aromatase, which is responsible for converting androgens into estrogen, thereby reducing estrogen levels in the body and slowing the growth of estrogen-dependent cancer cells. Tamoxifen, on the other hand, binds to estrogen receptors on cancer cells, blocking estrogen from binding and activating these receptors. These mechanisms are crucial for breast cancer patients because they target the hormonal pathways that fuel the growth of hormone receptor-positive breast cancer, thereby improving treatment outcomes and reducing the risk of recurrence.