Conditions: Breast Cancer
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 35
Healthy volunteers: no

Brief summary:
Many women with breast cancer who are treated with aromatase inhibitor medications develop aches and pains during treatment, and some develop numbness and tingling in their hands and feet. Some examples of aromatase inhibitor medications include anastrozole (Arimidex), exemestane (Aromasin), and letrozole (Femara). Frequently, pain medications do not work very well to relieve the pain. Duloxetine (Cymbalta) is a medication that was originally developed to treat depression. It has also been found to relieve pain that occurs in people with diabetes, fibromyalgia, arthritis, and other painful conditions. In this study we are testing to see if duloxetine will help treat the pain that can occur in women treated with aromatase inhibitors.

Detailed description:
Aromatase inhibitor (AI) therapy is commonly used for treatment of postmenopausal women with hormone receptor-positive breast cancer. The most common toxicities are arthralgias and myalgias, which can be difficult to manage and necessitate discontinuation of therapy in up to 10% of patients. One potential interventional approach is with a pharmaceutical agent such as duloxetine, which has been shown to be effective for treatment of other types of chronic pain, including fibromyalgia and diabetic neuropathic pain.

The primary objective of this pilot study is to determine the proportion of breast cancer patients with AI-associated musculoskeletal symptoms who experience a 30% reduction in average pain score from baseline to 8 weeks due to duloxetine treatment. Participants will be treated with duloxetine for 8 weeks. Questionnaires to evaluate pain, functional status, depression, menopausal symptoms, and sleep difficulties will be administered at baseline and after 2, 4, 6, and 8 weeks of therapy. In addition, 10 milliliters blood of will be drawn from the subjects at baseline for future pharmacogenetic evaluation. If the results of this pilot study suggest that the efficacy of duloxetine therapy is greater than that expected from placebo based on historical controls, then these data will be used to design future prospective, placebo-controlled, randomized trials of treatment with duloxetine in this patient population.

Arms:
arm 1: None

Interventions: intervention 1: Duloxetine
Intervention descriptions: intervention 1: Patients will be treated with open-label duloxetine:

* 30 mg daily x 7 days, then
* 60 mg daily x 3 weeks, then
* If a patient believes she has experienced a sufficient reduction in pain after 4 weeks of therapy, she will continue taking 60 mg daily for weeks 5-8
* If a patient does not believe she has experienced a sufficient reduction in pain after 4 weeks of therapy, she will have the option of increasing the dose to 60 mg twice daily for weeks 5-8.
* After completion of 8 weeks of therapy, patients who wish to discontinue therapy will taper off the drug over 1 week (50% decrease for 4 days, then additional 50% decrease for 3 days). Patients may continue therapy off-study at the discretion of their treating physician.

Protocol document: