Aromatase Inhibitors + Abemaciclib for Breast Cancer

(MONARCH 3 Trial)

Recruiting at 300 trial locations

Age: 18+

Sex: Female

Trial Phase: Phase 3

Sponsor: Eli Lilly and Company

Must be taking: Nonsteroidal aromatase inhibitors

Must not be taking: Endocrine therapy, Chemotherapy

Disqualifiers: Visceral crisis, CNS metastasis, others

Pivotal Trial (Near Approval) This treatment is in the last trial phase before FDA approval

Prior Safety Data This treatment has passed at least one previous human trial

Breakthrough Therapy This drug has been fast-tracked for approval by the FDA given its high promise

Compensation: Varies

Number of Visits: Unknown

Duration: Up to 32 months

493 Participants Needed

Trial Summary

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications. However, you cannot participate if you are currently receiving certain treatments like chemotherapy for breast cancer or investigational drugs. It's best to discuss your specific medications with the trial team.

What data supports the effectiveness of the drug combination of aromatase inhibitors and abemaciclib for breast cancer?

Research shows that abemaciclib, when combined with endocrine therapy, significantly improves outcomes for patients with hormone receptor-positive, HER2-negative advanced breast cancer, as seen in the MONARCH 2 and 3 trials. Additionally, aromatase inhibitors like letrozole and anastrozole are effective in treating hormone-sensitive metastatic breast cancer, making this combination a promising option. ^{1 2 3 4 5}

Is the combination of aromatase inhibitors and abemaciclib safe for humans?

The combination of abemaciclib and aromatase inhibitors has been shown to have a tolerable safety profile in patients with advanced breast cancer, with common side effects including diarrhea, neutropenia (low white blood cell count), and leukopenia (reduced white blood cells). ^{1 2 3 4 6}

How is the drug combination of aromatase inhibitors and Abemaciclib unique for breast cancer treatment?

This treatment combines aromatase inhibitors (which block estrogen production) with Abemaciclib (a drug that inhibits cancer cell growth), offering a novel approach by targeting both hormone production and cell division in breast cancer, potentially improving effectiveness compared to using aromatase inhibitors alone. ^{7 8 9 10 11}

What is the purpose of this trial?

The main purpose of this study is to evaluate how effective nonsteroidal aromatase inhibitors (NSAI) plus abemaciclib are in postmenopausal women with breast cancer. Participants will be randomized to abemaciclib or placebo in a 2:1 ratio.

Research Team

Call 1-877-CTLILLY (1-877-285-4559) or 1-317-615-4559 Mon - Fri 9 AM - 5 PM Eastern time (UTC/GMT - 5 hours, EST)

Principal Investigator

Eli Lilly and Company

Eligibility Criteria

This trial is for postmenopausal women with hormone receptor-positive, HER2-negative breast cancer who can swallow capsules and have either measurable disease or bone-only disease. They should not have received certain prior treatments like everolimus or chemotherapy for advanced breast cancer, nor should they have central nervous system metastasis or be in another conflicting study.

Inclusion Criteria

I am fully active and can carry on all pre-disease activities without restriction.

I've stopped and recovered from radiotherapy aimed at easing symptoms or preventing bone fractures.

My breast cancer is hormone receptor-positive and HER2-negative.

Exclusion Criteria

Are currently receiving an investigational drug in a clinical trial or participating in any other type of medical research judged not to be scientifically or medically compatible with this study

I haven't taken any unapproved drugs within the last 14 or 21 days, depending on the drug type.

I started treatment with bisphosphonates or RANK-L inhibitors less than a week ago.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive either 150 mg Abemaciclib or placebo orally every 12 hours plus either 1 mg anastrozole or 2.5 mg letrozole orally once daily for 28-day cycles

Up to 32 months

Follow-up

Participants are monitored for safety and effectiveness after treatment

4-8 weeks

Open-label extension (optional)

Participants may opt into continuation of treatment long-term

Long-term

Treatment Details

Interventions

• Abemaciclib
• Anastrozole
• Letrozole

Trial Overview The effectiveness of nonsteroidal aromatase inhibitors (like Anastrozole and Letrozole) combined with Abemaciclib versus a placebo is being tested. Participants will randomly receive either the drug combination or a placebo at a ratio of 2:1.

Participant Groups

Group I: Abemaciclib + NSAI Experimental Treatment 3 Interventions

150 milligrams (mg) Abemaciclib orally every 12 hours plus either 1 mg anastrozole or 2.5 mg letrozole orally once daily for 28 days (28 day cycles).

Group II: Placebo + NSAI Placebo Group 3 Interventions

Placebo orally every 12 hours plus either 1 mg anastrozole or 2.5 mg letrozole orally once daily for 28 days (28 day cycles).

Abemaciclib is already approved in United States, European Union for the following indications:

Approved in United States as Verzenio for:

• Hormone receptor-positive (HR+), human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer
• HR+, HER2- node-positive early breast cancer

Approved in European Union as Verzenio for:

• HR+, HER2- advanced or metastatic breast cancer
• HR+, HER2- node-positive early breast cancer

Who Is Running the Clinical Trial?

Eli Lilly and Company

Lead Sponsor

Trials

2,708

Recruited

3,720,000+

Dr. Daniel Skovronsky

Eli Lilly and Company

Chief Medical Officer since 2018

MD from Harvard Medical School

David A. Ricks

Eli Lilly and Company

Chief Executive Officer since 2017

BSc from Purdue University, MBA from Indiana University

Findings from Research

In a pooled analysis of 1152 patients from the MONARCH 2 and MONARCH 3 studies, abemaciclib combined with endocrine therapy showed a consistent improvement in progression-free survival (PFS) across all age groups, indicating its efficacy in treating HR+, HER2- advanced breast cancer regardless of age.

Older patients experienced higher rates of clinically relevant side effects, such as diarrhea and nausea, but these were manageable with dose adjustments, suggesting that while safety concerns exist, the treatment remains effective for older populations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety and efficacy of abemaciclib plus endocrine therapy in older patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer: an age-specific subgroup analysis of MONARCH 2 and 3 trials. Goetz, MP., Okera, M., Wildiers, H., et al.[2022]

In a phase III trial, abemaciclib combined with endocrine therapy significantly reduced the risk of breast cancer recurrence in patients with hormone receptor positive (HR+), HER2-negative, node-positive early breast cancer, regardless of prior chemotherapy or tumor characteristics.

The combination treatment was generally well-tolerated, with manageable side effects such as diarrhea, infections, and neutropenia, making it a valuable option for high-risk patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Abemaciclib: A Review in Early Breast Cancer with a High Risk of Recurrence. Fung, S., Blair, HA.[2023]

Interim results from the MONARCH3 study show that abemaciclib, a CDK4/6 inhibitor, is an effective first-line treatment for advanced ER-positive, HER2-negative breast cancer.

Patients receiving abemaciclib in combination with letrozole experienced significantly improved progression-free survival compared to those receiving a placebo with endocrine therapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

First-Line Abemaciclib Effective in ER+ Breast Cancer. [2019]

In a phase III study involving 493 postmenopausal women with HR-positive, HER2-negative advanced breast cancer, abemaciclib significantly improved progression-free survival compared to placebo, with a hazard ratio of 0.54, indicating a strong efficacy as initial therapy.

The most common side effect of abemaciclib was diarrhea, occurring in 81.3% of patients, but most cases were mild (grade 1), suggesting that while there are some adverse effects, the treatment has a tolerable safety profile.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

MONARCH 3: Abemaciclib As Initial Therapy for Advanced Breast Cancer. Goetz, MP., Toi, M., Campone, M., et al.[2022]

In a study involving 3697 postmenopausal women with hormone receptor-positive early breast cancer, the upfront treatment with aromatase inhibitors for 5 years did not show superior disease-free survival compared to a switch strategy of 2 years of tamoxifen followed by 3 years of aromatase inhibitors, with 5-year disease-free survival rates of 89.8% and 88.5%, respectively.

No significant differences in efficacy were found among the three aromatase inhibitors (anastrozole, exemestane, and letrozole), suggesting that factors like patient preference and tolerability should guide treatment decisions rather than efficacy alone.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Adjuvant anastrozole versus exemestane versus letrozole, upfront or after 2 years of tamoxifen, in endocrine-sensitive breast cancer (FATA-GIM3): a randomised, phase 3 trial. De Placido, S., Gallo, C., De Laurentiis, M., et al.[2019]

In a study using a breast tumor model with ovariectomized mice, letrozole was found to significantly extend the time for tumor progression compared to tamoxifen alone or in combination with letrozole, with letrozole alone allowing tumors to double in size after 34 weeks versus 16 weeks for tamoxifen.

Tumors that progressed while on tamoxifen remained sensitive to second-line treatment with letrozole, indicating a potential treatment pathway, while tumors progressing on letrozole did not respond to subsequent antiestrogen therapies, highlighting the need for further research on effective second-line options.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Therapeutic strategies using the aromatase inhibitor letrozole and tamoxifen in a breast cancer model. Long, BJ., Jelovac, D., Handratta, V., et al.[2022]

Anastrozole and letrozole are effective oral treatments for advanced breast cancer in postmenopausal women, especially when other therapies like tamoxifen have not worked.

Both drugs are claimed to be more effective and less toxic than the standard treatment, megestrol acetate, although the review assesses the validity of these claims.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

New aromatase inhibitors for breast cancer. [2019]

Three new third-generation aromatase inhibitors (anastrozole, letrozole, and vorozole) have shown superior efficacy and tolerability compared to previous treatments for post-menopausal women with metastatic breast cancer after tamoxifen therapy, based on phase III trials.

Letrozole is significantly more effective than megestrol acetate, while all three inhibitors are better tolerated than progestin treatments, particularly regarding weight gain, marking a clear advancement in second-line hormonal therapies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The third-generation non-steroidal aromatase inhibitors: a review of their clinical benefits in the second-line hormonal treatment of advanced breast cancer. Hamilton, A., Piccart, M.[2020]

References

1. Netherlands pubmed.ncbi.nlm.nih.gov

Safety and efficacy of abemaciclib plus endocrine therapy in older patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer: an age-specific subgroup analysis of MONARCH 2 and 3 trials. [2022]

2. France pubmed.ncbi.nlm.nih.gov

Abemaciclib: A Review in Early Breast Cancer with a High Risk of Recurrence. [2023]

3. United States pubmed.ncbi.nlm.nih.gov

First-Line Abemaciclib Effective in ER+ Breast Cancer. [2019]

4. United States pubmed.ncbi.nlm.nih.gov

A comparison of the efficacy of aromatase inhibitors in second-line treatment of metastatic breast cancer. [2019]

5. United States pubmed.ncbi.nlm.nih.gov

Aromatase inhibitors in early breast cancer therapy. [2019]

6. United States pubmed.ncbi.nlm.nih.gov

MONARCH 3: Abemaciclib As Initial Therapy for Advanced Breast Cancer. [2022]

7. England pubmed.ncbi.nlm.nih.gov

Adjuvant anastrozole versus exemestane versus letrozole, upfront or after 2 years of tamoxifen, in endocrine-sensitive breast cancer (FATA-GIM3): a randomised, phase 3 trial. [2019]

8. England pubmed.ncbi.nlm.nih.gov

Abiraterone acetate, exemestane or the combination in postmenopausal patients with estrogen receptor-positive metastatic breast cancer. [2022]

9. United States pubmed.ncbi.nlm.nih.gov

Therapeutic strategies using the aromatase inhibitor letrozole and tamoxifen in a breast cancer model. [2022]

10. England pubmed.ncbi.nlm.nih.gov

New aromatase inhibitors for breast cancer. [2019]

11. England pubmed.ncbi.nlm.nih.gov

The third-generation non-steroidal aromatase inhibitors: a review of their clinical benefits in the second-line hormonal treatment of advanced breast cancer. [2020]