Study to Assess Effect of 8 Wks of Duloxetine Therapy on Breast Cancer Patients With Aromatase-Inhibitor Associated Pain
Study to Assess Effect of 8 Wks of Duloxetine Therapy on Breast Cancer Patients With Aromatase-Inhibitor Associated Pain
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.
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.
Inclusion Criteria:

 -  Female;

 -  Histologically proven stage 0-III invasive carcinoma of the breast that is ER and/or
 PR positive by immunohistochemical staining, who are receiving a standard dose of
 aromatase inhibitor (AI) therapy (letrozole 2.5mg once daily or exemestane 25mg once
 daily or anastrozole 1mg once daily). Women with oligometastatic disease may be
 included at the discretion of the principal investigator. Surgical resection,
 chemotherapy, and radiation therapy must have been completed at the time of study
 enrollment, with the exception of trastuzumab;

 -  AI therapy has been ongoing for ≥ 2 weeks and treatment is expected to continue;

 -  AI-associated musculoskeletal symptoms, defined as:

 -  Grade 1 or higher musculoskeletal pain that developed or worsened (6 or 7 on
 CGICS) during AI therapy or

 -  Grade 1 or higher sensory neuropathy that developed or worsened (6 or 7 on CGICS)
 during AI therapy;

 -  Average pain of ≥4 on the 11-point Likert scale of question #5 of the Brief Pain
 Inventory;

 -  ECOG performance status 0-2;

 -  Willing and able to sign an informed consent document.

 Exclusion Criteria:

 -  Known hypersensitivity to duloxetine or any of the inactive ingredients;

 -  New musculoskeletal pain that is due specifically to fracture or traumatic injury;

 -  Treatment with monoamine oxidase inhibitors (MAO-I) within 14 days of enrollment;

 -  Concurrent treatment with phenothiazines (including thioridazine), propafenone,
 flecainide, triptans, MAO-Is, SSRIs, SNRIs, or tricyclic antidepressants;

 -  Currently primary psychiatric diagnosis (schizophrenia, psychosis) or suicidal
 ideation, history of bipolar disorder, or seizure disorder;

 -  Chronic liver disease, end stage renal disease, or creatinine clearance < 30 mL/min as
 defined by the Cockroft-Gault equation;

 -  Uncontrolled narrow-angle glaucoma or clinically significant coagulation disorder;

 -  Pregnant or breast feeding;

 -  History of alcohol or other substance abuse or dependence within the year prior to
 enrollment;

 -  Serious or unstable medical condition that could likely lead to hospitalization during
 the course of the study or compromise study participation.