Eribulin in Combination With Cyclophosphamide in Patients With Solid Tumor Malignancies

The purpose of this study is to test the safety of eribulin (Halaven™) and cyclophosphamide (Cytoxan®) given together at different doses. This study will look at what effects, good and/or bad, that these drugs have on solid tumors. Eribulin is a drug that has been approved by the FDA for breast cancer that has spread to other parts of the body. Cyclophosphamide has been approved for different types of cancers (including breast cancer). However, the combination of eribulin and cyclophosphamide is considered experimental; that means this combination has not been approved by the FDA. The funding for this study is provided by Eisai Inc., the maker of eribulin.

This is a phase Ib/II trial designed to determine the maximum tolerated dose (MTD) and does limiting toxicities (DLTs) of the combination of eribulin and cyclophosphamide in solid tumors and make preliminary estimates regarding efficacy of this treatment in patients with advanced breast cancer. The study includes a standard dose-confirmation schema (phase Ib portion) enrolling 3 to 6 patients/subjects, with any solid tumors, per cohort (3+3 design) with a total of 18 patients. The dose-expansion (phase II portion) will enroll 40 patients with advanced breast cancer to detect an effect size of 15% with a power of 80% with endpoints of safety, efficacy, and clinical benefit rate. A maximum of 58 patients will be enrolled on the phase Ib and II portions of this trial combined and will be treated until disease progression or toxicity mandate treatment change. Eribulin is a non-taxane microtubule inhibitor that is FDA approved as monotherapy for the treatment of taxane and anthracycline resistant metastatic breast cancer. The combination of docetaxel and cyclophosphamide is a well-accepted adjuvant chemotherapy regimen that has become an increasingly common therapeutic choice for intermediate risk early stage breast cancer. Eribulin has a favorable toxicity profile compared to docetaxel with the most common adverse reactions (incidence ≤25%) including neutropenia, anemia, asthenia/fatigue, alopecia, peripheral neuropathy, nausea, and constipation. Eribulin appears to have activity in taxane resistant disease, making it an attractive partner with cyclophosphamide. Neuropathy can be a devastating complication from adjuvant chemotherapy and in the metastatic setting, may limit effective therapy and reduce quality of life. Understanding the host factors that predict risk for neuropathy is critical, as these patients may in particular benefit from the lower risk of neuropathy associated with eribulin therapy. In conjunction with this trial, we have included correlative studies to study the proposed pharmacogenomic factors associated with risk of neuropathy. In this way we will potentially be able to identify patients who could preferentially be treated with less neurotoxic microtubule inhibitors.