Phase II study of eribulin mesylate (E7389), a mechanistically novel inhibitor of microtubule dynamics, in patients with advanced non-small cell lung cancer (NSCLC)

Abstract

7546 Background: Eribulin is a structurally-simplified, fully synthetic analog of the marine sponge natural product halichondrin B. Eribulin inhibits microtubule dynamics via a mechanistically novel mode of action. Methods: An open-label, single-arm, Phase II study of eribulin was conducted in patients with advanced NSCLC (ECOG of 0 or 1) who were treated with platinum-based doublet chemotherapy and stratified by prior taxane exposure. A total of 103 patients (83 with prior taxanes and 20 taxane naïve) were treated with eribulin (1.4 mg/m 2 ), administered as a bolus infusion over 2 –5 minutes on Days 1, 8, and 15 of a 28-day cycle (N=77). Due to delays or skipped doses secondary to myelosuppression at Day 15 with recovery by Day 21, the protocol was amended to a schedule of Days 1 and 8 of a 21-day cycle (N=26). The primary efficacy endpoint was objective response rate. Independent radiologic review was used to confirm responses. Results: Of 106 enrolled patients, 103 received eribulin. Median age was 65 years and median number of prior therapies was 2, including taxanes (81%), gemcitabine (40%), pemetrexed (23%), and EGFR inhibitors (34%). Median number of cycles administered was 3 (range 1–15). Drug related toxicities included neutropenia grade 3 (23%) and 4 (26%), febrile neutropenia (4%), grade 3 fatigue (11%), grade 3 nausea (2%), and peripheral neuropathy grade 1/2 (37%) and 3 (2%). Based on RECIST criteria, the overall response rate (all partial responses) was 9.7% (95% CI: 4.0–15.4 %), with 10.8% PR in taxane pre-treated, and 5% PR in taxane naïve patients. Overall disease control rate (PR + SD) was 55.3%. 12-week progression free survival (PFS) rate was 53.0% (95% CI: 42.6–63.3%) and median PFS was 102 days (range 1–408+). Median duration of response was 176 days (range 50–291+), and median overall survival was 287 days (range 16–423+). The one year survival rate was 46.4% (95% CI: 34.9–58.0%). Conclusions: In this group of NSCLC patients who were treated with a median of two prior therapies, consisting in the majority of cases of two cytotoxic regimens, eribulin demonstrated an overall PR rate of 9.7% (10.8% in the taxane pre-treated) and 9.6 months median survival. No significant financial relationships to disclose.