PET/CT Guided Fulvestrant Therapy for Patients With Recurrent or Metastatic Breast Cancer

A Phase II Clinical Trial to Evaluate 18F-Fluoroestradiol Positron Emission Tomography / Computerized Tomography (PET/CT) Guided Fulvestrant Therapy for Patients With Recurrent or Metastatic Breast Cancer

Purpose:

To determine whether [18F]FES can predict clinical benefit (defined as complete response, partial response and stable disease ≥ 6 months) to fulvestrant (250 mg IM q 28 days) in post-menopausal women with recurrent or metastatic ER+ breast cancer who are candidates for further hormonal therapy.

The majority of women diagnosed with breast cancer are post-menopausal, of which up to 75% are estrogen (ER) and/or progesterone receptor (PR) positive. Even in pre-menopausal breast cancer over half of all patients will have expression of these hormone receptors. Thus therapeutic strategies targeting the estrogen receptor or its ligand are the most common treatment offered in breast cancer. Despite substantial benefits now demonstrated with selective estrogen receptor modulators (e.g. tamoxifen) and aromatase inhibitors (e.g. anastrazole, letrozole and exemestane), a significant proportion of patients will still unfortunately have or develop resistance to these hormonal therapies.

Despite approximately two-thirds of patients who are prescribed fulvestrant following prior hormonal agents not benefiting from this therapy, clinicians are still offering this option to all suitable women because of the lack of a better means of identifying the individual responders.

To assess whether the recommended treatment is beneficial to a specific individual, the disease burden is assessed before and following treatment. Conventional imaging techniques such as the bone scan or computerized tomography (CT) can take several months to show a successful response to treatment. Positron emission tomography (PET) can improve the evaluation of women with breast cancer by providing an accurate assessment of the extent of disease and unique information about tumor biology such as metabolic activity.

Inclusion Criteria:

• post-menopausal (≥ 60 years old, or age ≥ 45 years with amenorrhea for > 12 months or follicle stimulating hormone and estrogen levels within post-menopausal range, or prior bilateral oophorectomy)
• hormone receptor positive (ER and/or PgR) disease as determined locally
• WHO performance status 0-2
• life expectancy of ≥ 3 months
• the presence of at least one measurable or evaluable (non-measurable) lesion
• informed consent prior to any study procedures

Exclusion Criteria:

• life threatening metastatic visceral disease
• brain or leptomeningeal metastases
• prior exposure to fulvestrant
• history of bleeding diathesis or need for long term anti-coagulation