Phase II study of eribulin in combination with gemcitabine for the treatment of patients with locally advanced or metastatic triple negative breast cancer: ERIGE trial on behalf of the Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC).

Background: There are no well-established chemotherapy regimens for metastatic triple negative breast cancer. The combination of a microtubule inhibitor (eribulin) with a nucleoside analog (gemcitabine) may synergistically induce tumor cell death, especially in tumors like triple negative breast cancers (TNBC) characterized by high cell proliferation, aggressive tumor behavior, and chemo-resistance. Methods: We performed an open-label, national multicenter phase 2 study evaluating the combination of eribulin (0.88 mg/m2) plus gemcitabine (1000 mg/m2) on day 1 and 8, q21 as either first- or second-line treatment of locally advanced or metastatic TNBC. The Simon's optimal two-stage design was used for estimating objective response rate (ORR) as study primary endpoint. A prospective, molecular correlative study was carried out on germinal DNA of study population to assess the role of germinal DNA polymorphisms and BRCA mutations in predicting efficacy and toxicity of the combination regimen. Results: From July 2013 to September 2016, 83 (37 in the first stage, 46 in the second one) assessable patients were enrolled. Median age at baseline was 56 years. Sixty-six and 17 patients were in first or second-line treatment, respectively. All patients were previously treated with an anthracycline and/or a taxane. With regard to the first stage of study enrolment, patients received a median number of 6 cycles of treatment. The ORR (CR+PR) was 43.24% (90% CI 29.3-58.0) and the clinical benefit rate (CR+PR+SD) was 64.9% (90% CI: 50.1%-77.8%). The most common grade 3/4 AEs ( > 10% of patients) were neutropenia without febrile neutropenia and liver toxicity. Grade 1/2 AEs were fatigue, anemia, thrombocytopenia, diarrhea, alopecia, peripheral neuropathy, and oral mucositis. Conclusions: The combination of eribulin and gemcitabine shows promising activity and a moderate toxicity profile in metastatic TNBC. More mature toxicity and outcome data of the final study population and correlation with genome analysis will be presented at the meeting. Clinical trial information: 2012-003505-10.