MADRID, SPAIN-Preliminary results of a phase III trial comparing capecitabine(Drug information on capecitabine) (Xeloda) and oxaliplatin(Drug information on oxaliplatin) (Eloxatin)(CapeOx) with oxaliplatin and fluorouracil(Drug information on fluorouracil) (5-FUOx) show similar efficacy and tolerability for both regimens in first-line treatment of advanced or metastatic colorectal cancer, Javier Sastre, MD, said. Dr. Sastre of the Hospital Clinical San Carlos, Madrid, Spain, reported the early results (abstract 3524). Dr. Sastre said that the phase III trial was designed because both regimens had promising phase II efficacy. He noted that oxaliplatin plus contin uous infusion 5-FU is one of the standard chemotherapy regimens for firstline treatment in patients with advanced colorectal cancer and that phase II trials have shown CapeOx is a convenient combination, with a high activity and a favorable safety profile. The study was intended to include 348 patients with advanced or metastatic colorectal cancer. Previous adjuvant chemotherapy was allowed. Patients were randomized to one of two arms: Arm A consisted of oral capecitabine (1,000 mg/m2 twice daily from day 1 to day 15) plus oxaliplatin (130 mg/m2, 2-hour IV infusion on day 1), with cycles repeating every 3 weeks; Arm B contained oxaliplatin (85 mg/m2, 1-hour IV infusion biweekly) plus 5-FU (2,250 mg/m2 as a weekly continuous infusion). Both Regimens Well Tolerated Dr. Sastre reported an interim analysis of patient characteristics including 324 of 348 enrolled patients, with a median age of 65.9 years. Primary tumor sites were the colon (65%), rectum (28%), and both (6.1%). Sixty- eight percent of patients had only one disease site, mainly the liver (76.1%), lungs (31.5%), and lymph nodes (12.0%). Eighty-two percent of patients had undergone prior surgery, 22% had undergone prior adjuvant chemotherapy, and 12% had undergone prior radiotherapy. The median relative dose intensity was 90% for capecitabine and 93% for oxaliplatin in arm A and 80% for oxaliplatin and 78% for 5-FU in arm B. Dr. Sastre reported similar and very promising efficacy for both regimens in 260 patients, with overall response rates of 50% with CapeOx and 53% with 5-FU-Ox (Table 1). CapeOx was associated with significantly more grade 1 or 2 mucositis, bilirubinemia, hand-foot syndrome, and anemia, whereas 5-FU-Ox caused significantly more grade 3 or 4 diarrhea. "Safety results suggest a favorable toxicity profile for both regimens. Preliminary efficacy results suggest equivalent high efficacy for both regimens. Both regimens are feasible and well tolerated as first-line treatment for metastatic colorectal cancer," Dr. Sastre concluded.