Fulvestrant vs Anastrozole for Breast Cancer

(FALCON Trial)

Recruiting at 103 trial locations

Age: 18+

Sex: Female

Trial Phase: Phase 3

Sponsor: AstraZeneca

Disqualifiers: Life-threatening metastasis, Extensive hepatic, Brain involvement, Symptomatic pulmonary, Prior systemic therapy, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

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

Compensation: Varies

Number of Visits: 24

Duration: 38 months

462 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, but it does mention that you should not have had prior hormonal treatment for breast cancer. If you've had chemotherapy, the last dose must have been more than 28 days before joining the trial.

What data supports the effectiveness of the drugs Fulvestrant and Anastrozole for breast cancer?

Research shows that Fulvestrant and Anastrozole are similarly effective for treating advanced breast cancer in postmenopausal women, with both drugs providing clinical benefits. Fulvestrant is particularly valuable for women with visceral metastases (cancer spread to internal organs) who have not responded to previous hormone treatments. ^{1 2 3 4 5}

What is the safety profile of Fulvestrant and Anastrozole for breast cancer treatment?

Anastrozole (Arimidex) has been shown to have fewer gynecologic side effects compared to tamoxifen in breast cancer treatment. Fulvestrant (Faslodex) and Anastrozole have similar safety profiles when used for advanced breast cancer in postmenopausal women. ^{1 2 3 6 7}

How does the drug Fulvestrant differ from Anastrozole in treating advanced breast cancer?

Fulvestrant is unique because it is a selective estrogen receptor degrader that works by breaking down estrogen receptors, whereas Anastrozole is an aromatase inhibitor that reduces estrogen production. Fulvestrant is administered as an intramuscular injection, while Anastrozole is taken orally. Fulvestrant has shown to be more effective in prolonging progression-free survival in certain patients compared to Anastrozole. ^{1 2 3 8 9}

What is the purpose of this trial?

The purpose of the study is to compare how treatment with Fulvestrant (FASLODEX) or Anastrozole (ARIMIDEX) effects disease progression for women with locally advanced or metastatic breast cancer who have not had prior hormonal treatment.

Research Team

Matthew Ellis, DM

Principal Investigator

Washington University School of Medicine, USA

Shankar S, MD

Principal Investigator

AstraZeneca

John Robertson, MD

Principal Investigator

Graduate Medicine and Health School, University of Nottingham, UK

Eligibility Criteria

This trial is for postmenopausal women aged 60 or above with breast cancer that's either locally advanced or metastatic, and who haven't had hormonal treatment before. They should have a positive hormone receptor status and can have had one chemotherapy line if there's still disease progression.

Inclusion Criteria

I have advanced or metastatic cancer and have had only one chemotherapy treatment.

I am a postmenopausal woman, either by surgery, age, or natural causes.

I have at least one tumor that can be measured and monitored over time.

Exclusion Criteria

I have received hormone therapy for breast cancer.

My cancer has spread to other parts of my body and is life-threatening.

My cancer has not severely affected my liver, brain, or lungs.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive either Fulvestrant or Anastrozole as hormonal treatment for breast cancer

38 months

Every 12 weeks

Follow-up

Participants are monitored for safety and effectiveness after treatment

up to 116 months

12 weekly intervals for survival status

Treatment Details

Interventions

• Anastrozole
• Fulvestrant

Trial Overview The study compares the effects of two drugs on breast cancer: Fulvestrant (FASLODEX) at 500mg versus Anastrozole (ARIMIDEX) at 1mg. It aims to see which drug better slows down disease progression in patients who haven't received prior hormonal therapy.

Participant Groups

Group I: faslodex+placebo Experimental Treatment 2 Interventions

Blinded: Fulvestrant 500mg intramuscular injection (2x250mg) plus dummy Anastrozole tablets

Group II: arimidex +placebo Active Control 2 Interventions

Blinded: Anastrozole 1mg tablets plus dummy Fulvestrant intramuscular injection (2x0mg)

Anastrozole is already approved in European Union, United States, Canada, Japan for the following indications:

Approved in European Union as Arimidex for:

• Breast cancer
• Early breast cancer in postmenopausal women

Approved in United States as Arimidex for:

• Adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer
• First-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor unknown locally advanced or metastatic breast cancer

Approved in Canada as Arimidex for:

• Adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer
• Treatment of postmenopausal women with hormone receptor-positive advanced breast cancer

Approved in Japan as Arimidex for:

• Breast cancer

Who Is Running the Clinical Trial?

AstraZeneca

Lead Sponsor

Trials

4,491

Recruited

290,540,000+

Sir Pascal Soriot

AstraZeneca

Chief Executive Officer since 2012

Veterinary Medicine from École nationale vétérinaire d'Alfort, MBA from HEC Paris

Dr. Cristian Massacesi

AstraZeneca

Chief Medical Officer since 2021

MD from Marche Polytechnic University, Oncology training at Royal Marsden Hospital, Kaplan Comprehensive Cancer Center, and European Institute of Oncology

Pascal Soriot

AstraZeneca

Chief Executive Officer since 2012

Veterinary Medicine from École nationale vétérinaire d'Alfort, MBA from HEC Paris

Cristian Massacesi

AstraZeneca

Chief Medical Officer since 2021

MD from Marche Polytechnic University, Medical Oncology training at Royal Marsden Hospital, Kaplan Comprehensive Cancer Center, and European Institute of Oncology

Findings from Research

Fulvestrant (Faslodex) is as effective as anastrozole (Arimidex) for treating advanced breast cancer in postmenopausal women, with similar objective response rates across different patient subgroups.

Both treatments provided comparable clinical benefits, making fulvestrant a valuable option for patients with visceral metastases who have not responded to previous endocrine therapies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Fulvestrant (Faslodex) versus anastrozole for the second-line treatment of advanced breast cancer in subgroups of postmenopausal women with visceral and non-visceral metastases: combined results from two multicentre trials. Mauriac, L., Pippen, JE., Quaresma Albano, J., et al.[2019]

Anastrozole is as effective as tamoxifen for treating advanced breast cancer in postmenopausal women, showing a slightly higher objective response rate (21% vs. 17%) and a significant clinical benefit in 59% of patients compared to 46% for tamoxifen.

Anastrozole offers a significant advantage in time to progression (median of 11.1 months vs. 5.6 months for tamoxifen) and has a lower incidence of side effects, such as thromboembolic events and vaginal bleeding, making it a preferable first-line therapy option.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Anastrozole is superior to tamoxifen as first-line therapy for advanced breast cancer in postmenopausal women: results of a North American multicenter randomized trial. Arimidex Study Group. Nabholtz, JM., Buzdar, A., Pollak, M., et al.[2022]

In a study of 6241 postmenopausal women with early-stage breast cancer, anastrozole was found to have significantly fewer treatment-related adverse events compared to tamoxifen, indicating better tolerability.

Anastrozole also demonstrated a more favorable risk-benefit profile, with lower rates of serious adverse events and recurrence compared to tamoxifen, making it a preferable option for adjuvant treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comprehensive side-effect profile of anastrozole and tamoxifen as adjuvant treatment for early-stage breast cancer: long-term safety analysis of the ATAC trial. Buzdar, A., Howell, A., Cuzick, J., et al.[2022]

In a study involving 668 postmenopausal women with advanced breast cancer, anastrozole was found to be as effective as tamoxifen, with similar median time to progression (8.2 months for anastrozole vs. 8.3 months for tamoxifen).

Anastrozole demonstrated a lower incidence of side effects, such as thromboembolic events (4.8% vs. 7.3%) and vaginal bleeding (1.2% vs. 2.4%), suggesting it may be a safer first-line treatment option for advanced breast cancer.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Anastrozole versus tamoxifen as first-line therapy for advanced breast cancer in 668 postmenopausal women: results of the Tamoxifen or Arimidex Randomized Group Efficacy and Tolerability study. Bonneterre, J., Thürlimann, B., Robertson, JF., et al.[2022]

In a study of 54 postmenopausal women with metastatic breast cancer, fulvestrant demonstrated clinical benefit in 38.9% of patients, with a median time to progression of 6.4 months, indicating its efficacy even after multiple prior treatments.

Fulvestrant was well tolerated, with no severe toxicities (grade 3/4) reported, suggesting it is a safe option for patients with advanced breast cancer who have limited treatment options.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Fulvestrant ('Faslodex') in heavily pretreated postmenopausal patients with advanced breast cancer: single centre clinical experience from the compassionate use programme. Mlineritsch, B., Psenak, O., Mayer, P., et al.[2018]

In a retrospective analysis of the ATAC trial, women taking tamoxifen experienced significantly more gynecologic adverse events (34.2%) compared to those taking anastrozole (20.5%), leading to more medical interventions, including a nearly fourfold increase in hysterectomies.

The findings support the use of anastrozole as the preferred initial treatment for early hormone receptor-positive breast cancer due to its lower incidence of gynecologic complications, particularly since most adverse events with tamoxifen occurred within the first 2.5 years.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A lower incidence of gynecologic adverse events and interventions with anastrozole than with tamoxifen in the ATAC trial. Duffy, SR., Distler, W., Howell, A., et al.[2018]

Fulvestrant is a new antiestrogen that has been shown to be effective in treating postmenopausal women with advanced breast cancer, especially after they have not responded to tamoxifen, and it has no partial agonistic effects unlike tamoxifen.

Clinical studies have demonstrated that fulvestrant has comparable efficacy to anastrozole and good tolerance among patients, leading to its approval for use in the USA and EU for those who have progressed on prior anti-estrogen therapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Fulvestrant: a new agent in endocrine treatment for breast cancer]. Juretić, A., Sarić, N., Bisof, V., et al.[2018]

References

1. England pubmed.ncbi.nlm.nih.gov

Fulvestrant (Faslodex) versus anastrozole for the second-line treatment of advanced breast cancer in subgroups of postmenopausal women with visceral and non-visceral metastases: combined results from two multicentre trials. [2019]

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

Anastrozole is superior to tamoxifen as first-line therapy for advanced breast cancer in postmenopausal women: results of a North American multicenter randomized trial. Arimidex Study Group. [2022]

3. England pubmed.ncbi.nlm.nih.gov

Comprehensive side-effect profile of anastrozole and tamoxifen as adjuvant treatment for early-stage breast cancer: long-term safety analysis of the ATAC trial. [2022]

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

Anastrozole versus tamoxifen as first-line therapy for advanced breast cancer in 668 postmenopausal women: results of the Tamoxifen or Arimidex Randomized Group Efficacy and Tolerability study. [2022]

5. Netherlands pubmed.ncbi.nlm.nih.gov

Fulvestrant ('Faslodex') in heavily pretreated postmenopausal patients with advanced breast cancer: single centre clinical experience from the compassionate use programme. [2018]

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

Influence of comorbidities and age on risk of death without recurrence: a retrospective analysis of the Arimidex, Tamoxifen Alone or in Combination trial. [2022]

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

A lower incidence of gynecologic adverse events and interventions with anastrozole than with tamoxifen in the ATAC trial. [2018]

8. Croatia pubmed.ncbi.nlm.nih.gov

[Fulvestrant: a new agent in endocrine treatment for breast cancer]. [2018]

9. New Zealand pubmed.ncbi.nlm.nih.gov

Fulvestrant: A Review in Advanced Breast Cancer Not Previously Treated with Endocrine Therapy. [2018]