Abstract OT3-3-01: Eniluracil + 5-fluorouracil + leucovorin (EFL) vs. capecitabine phase 2 trial for metastatic breast cancer

Based on a modified dosing protocol designed to optimize efficacy, an open-label EFL vs . capecitabine (4:3 randomization) Phase 2 trial for metastatic breast cancer is in progress. Eniluracil inactivates dihydropyrimidine dehydrogenase, thereby preventing the formation of α-fluoro-β-alanine, and conferring 100% oral bioavailability and a 5 hr half-life on 5-fluorouracil (5-FU). Study drugs are administered orally for 1 st - or 2 nd -line treatment for metastatic disease in patients previously treated with an anthracycline and a taxane. Arm 1: eniluracil (40 mg) taken 11–16 hr before 5-FU (30 mg/m 2 ); leucovorin (30 mg) taken with 5-FU and the next day. The regimen is administered once/week for 3 weeks/4 weeks. Arm 2: capecitabine (1000 mg/m 2 ) taken bid for 14 days/21days. Arm 2 patients with disease progression could crossover to take EFL in Arm X. Two sites in the USA and 19 in Russia are enrolling. Currently, 115 patients (21% are 1 st -line, 70% had previous 5-FU treatment) are enrolled and 83 have had tumor assessments. EFL was well tolerated with no unexpected toxicities. As of May 2012, there were 11, 7, & 1 partial responses in Arms 1, 2, & X, respectively. The primary endpoint, progression-free survival, will be determined approximately 7.5 months after the trial is enrolled with 140 evaluable patients. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT3-3-01.