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How long can you take Faslodex?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on June 19, 2023.

Official answer

by Drugs.com

Key Points

  • Faslodex (fulvestrant) is a drug therapy used in women to treat advanced or metastatic breast cancer. In consultation with your doctor, you may continue Faslodex treatment as long as you are having a positive effect without serious side effects. Faslodex may be also combined with other medications to increase its effectiveness, if needed.
  • Drug therapy regimens are individualized for each person with advanced breast cancer. Your doctor will follow your progress and provide information about your length of treatment.
  • Faslodex is given as an intramuscular shot every month, In the first month, you’ll need a shot every two weeks to help build up your medication levels.

Faslodex studies

Looking at clinical studies submitted to the FDA for approval of Faslodex can give you an idea of how well other women responded to Faslodex treatment. Your circumstance is individual and these results may not apply to you specifically, so it's always best to discuss clinical trial results with your doctor. There may be other studies, as well.

FALCON Phase III study

In the FALCON study, Faslodex was compared to anastrozole (Arimidex), another hormonal therapy in 462 postmenopausal women with advanced or metastatic breast cancer. Most women (99%) had not been previously treated with endocrine therapy. However, some women may have received chemotherapy or radiation treatment prior to the study.

Women in the study had breast cancer that had spread to other parts of the body, including the lungs, liver, lymph nodes, or bones. Some women had cancer that spread to more than 1 location.

Faslodex 500 mg was compared with anastrozole (Arimidex) 1 mg, another drug used to treat hormone receptor positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer. The researchers looked at how well the treatments worked when compared to each other and they also evaluated side effects.

Results showed that Faslodex extended the progression-free survival time, which is the length of time during and after treatment that patients lived without their cancer getting worse, when compared with anastrozole 1 mg.

  • In the Faslodex 500 mg group, progression-free survival was a median of 16.6 months.
  • In the anastrozole 1 mg group, the progression-free survival was a median of 13.8 months.

Progression-free survival can be reported as the middle number of a range of months, also known as the median. The results were significant, which means that it is most likely the outcome occurred due to treatment and not just by chance.

Based on the results of FALCON, Faslodex may be prescribed as the first hormonal medicine for HR-positive, HER2-negative advanced breast cancer in postmenopausal women.

Combination treatment studies with Faslodex

Faslodex has also been studied in combination with palbociclib (Ibrance), abemaciclib (Verzenio) and ribociclib (Kisqali), all of which are CDK 4 and CDK 6 inhibitors. CDK 4/6 inhibitors help to block proteins to slow down cell division that leads to new cancer cell growth.

Faslodex combination therapy is used to treat:

  • HR-positive, HER2-negative advanced or metastatic breast cancer, in combination with ribociclib (brand name: Kisqali) in postmenopausal women as initial endocrine-based therapy or following disease progression on endocrine therapy.
  • HR-positive, HER2-negative advanced or metastatic breast cancer, in combination with palbociclib (brand name: Ibrance) or abemaciclib (brand name: Verzenio) in women with disease progression following endocrine therapy.

The combination of Faslodex with one of these drugs may extend the length of time, during and after treatment, that you can live without your disease getting worse (progression-free survival).

Faslodex plus Kisqali (MONALEESA-3 Study)

  • When Faslodex was used with ribociclib (Kisqali), the median progression-free survival time was 20.5 months compared to 12.8 months when Faslodex was used with a placebo.
  • The results were statistically significant and resulted in a 60% improvement in progression-free survival.
  • Faslodex plus Kisqali may be an option for you if you are postmenopausal with HR-positive, HER2-negative advanced or metastatic breast cancer, and have either not been previously treated with endocrine therapy, or have been previously treated with endocrine therapy but your disease progressed.

Faslodex plus Ibrance (PALOMA-3 study)

  • When Faslodex was studied in combination with palbociclib (Ibrance), women using this combination had a median progression free survival of 9.5 months compared to 4.6 months for the group that received Faslodex plus a placebo (an inactive treatment).
  • These results were statistically significant, and almost doubled the time of progression free survival compared to Faslodex alone.
  • Using Faslodex with Ibrance may be one option to treat HR-positive, HER2-negative advanced or metastatic breast cancer in women with disease progression after endocrine therapy.

Faslodex plus Verzenio (MONARCH-2 Study)

  • In the abemaciclib (Verzenio) studies used with Faslodex, the median progression-free survival was 16.4 months compared to 9.3 months for the group receiving Faslodex plus a placebo.
  • Faslodex plus Verzenio may be one choice to treat HR-positive, HER2-negative advanced or metastatic breast cancer in women with disease progression, if the cancer has spread after endocrine therapy.

Related Questions

How is Faslodex given?

Faslodex is given as a slow, intramuscular (into the muscle) injection into the buttocks (gluteal area). After the first month of treatment you’ll only need to receive it once per month.

It is given as two 5 milliliter (mL) injections, one in each buttock, on days 1, 15, 29 in the first month, and then once monthly thereafter. You may need a lower dose if you have liver disease.

Faslodex may cause nerve damage related to the injection. Call your doctor if you develop any of the following symptoms in your legs following injection: numbness, tingling, or weakness.

What are the common side effects with Faslodex?

Side effects, some serious, can occur with Faslodex treatment. You may have other side effects when Faslodex is used in combination with other medications. Speak to your doctor about what side effects you can expect. Contact your doctor immediately if you are concerned about any side effects of your treatment.

Common side effects of Faslodex include:

  • injection site pain
  • nausea
  • muscle, joint, and bone pain
  • headache
  • back pain
  • tiredness
  • hot flashes
  • vomiting
  • loss of appetite
  • weakness
  • cough
  • shortness of breath
  • constipation
  • increased liver enzymes
  • diarrhea

Faslodex may cause fertility problems in both women and men.

Bottom Line

  • Faslodex is used in postmenopausal women with hormone-related breast cancer that is advanced or has spread to other parts of the body (metastatic).
  • You will usually continue taking Faslodex treatment as long as you are having a positive effect without serious side effects.
  • Each patient's treatment plan is unique for them, and your doctor can give you a better idea of your treatment length based on your specific needs.

This is not all the information you need to know about Faslodex for safe and effective use. Review the full Faslodex product information here, and discuss this information with your doctor or other health care provider.

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