Efficacy and Tolerability of Eribulin Plus Lapatinib in Patients With Metastatic Breast Cancer (E-VITA)

* Lapatinib in combination with capecitabine has been approved for the treatment of women with HER-2-positive advanced breast cancer that have progressed after anthracycline-, taxane-, and trastuzumab-containing therapies. The use of this combination is limited by overlapping toxicity such as diarrhea and cutaneous side effects. * A significant number of patients receive today capecitabine with trastuzumab as first- or second-line treatment. Therefore, other combinations of lapatinib with less toxic cytotoxic agents are needed. * Eribulin mesylate (E7389) is a synthetic analog of Halichondrin B (HalB), a large polyether macrolide isolated from a marine sponge. Eribulin is a mechanistically unique antagonist of microtubule dynamics among tubulin-targeted agents, leading to inhibition of microtubule growth in the absence of effects on microtubule shortening, and formation of non- productive tubulin aggregates. * Eribulin mesylate at a dose of 1.4 mg/m² given on day 1, 8 every 3 weeks has shown better overall survival by 2.5 months compared to treatment of physicians choice in patients with locally advanced or metastatic breast cancer who were previously treated for 2-5 lines with anthracyclines, taxanes, and capecitabine (EMBRACE study). * The most frequently reported eribulin-related AEs were asthenia/fatigue (65%), alopecia (60%), neutropenia (60%), nausea (44%), anemia (28%), pyrexia (23%), leucopenia (22%), anorexia (21%), constipation (19%), vomiting (18%), and peripheral neuropathy (5.5%; only grade 3). Grade 4 neutropenia occurred in 32% of patients, and febrile neutropenia occurred in 5.5% of patients. The frequency of all other grade 3/4 AEs was less than 3%. This toxicity profile does not overlap with that of lapatinib. * There is uncertainty in how far a once every 3 week schedule of eribulin mesylate at a dose of 2.0 mg/m² would be better tolerated. Several phase II studies are currently conducted in various non-breast cancer indications to compare the d1+