Alternating irinotecan with oxaliplatin combined with UFT plus leucovorin (LV) (SCOUT) in patients with advanced colorectal cancer (ACRC): A phase I/II study

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4084 Background: The feasibility of UFT (tegafur-uracil) plus LV with alternating irinotecan and oxaliplatin was investigated in a two-stage, phase I/II, open-label, dose-finding trial in patients with ACRC. The study is now closed. Here we present results from the phase II cohort and overall results from the phase I/II study. Methods: Eligible patients aged =18 years had histologically confirmed, advanced, inoperable, measurable metastatic disease, no prior chemotherapy other than adjuvant bolus 5-FU administered =6 months previously, and adequate hematologic, hepatobiliary, and renal function. Patients in the phase I study received irinotecan 180 mg/m2 on d1, oxaliplatin 85–100 mg/m2 on d15 plus UFT 200–300 mg/m2/d with LV 90 mg/d on d1–21 of a 28-d cycle. Diarrhea, lethargy, and vomiting were dose limiting. The maximum tolerated dose (MTD) established was irinotecan 180 mg/m2, oxaliplatin 100 mg/m2, UFT 250 mg/m2/d, and LV 90 mg/day. Patients were treated at the MTD in the phase II study. Primary endpoints in the phase II study were objective response rate (ORR) and time to progression (TTP). Results: Forty-five patients (median age 62 [range 24–79] years, median 4 marker lesions) were entered, 16 and 29 patients in the phase I and II studies, respectively. The ORR in all 38 evaluable patients was 66% (95% CI 49–80%), with clinical benefit (CB) in 89% (95% CI 75–97%). At a median follow-up of 10.3 months, median TTP was 8.5 months (95% CI -7.6 to 10.4 months) in 40 evaluable patients and median OS (ITT population; n=45) was 16.8 months (95% CI -11.3 to 28.3 months). In the phase II study (n=29) median TTP was 8.1 months (95% CI -6.7 to 11.3 months) and median OS was 19.6 months (95% CI -7.7 to >25.6 months); ORR in 25 evaluable patients was 68% (95% CI -46.5 to 85.1%) with CB in 100% (95% CI -86.3 to 100%). Of 30 patients with confirmed radiologic progression, 21 (70%) had second-line therapy. At the MTD, 3 patients (10%) had grade 3 diarrhea, 1 patient (3%) had grade 3 neurotoxicity, and 2 patients (7%) had grade 2 alopecia. No hand-foot syndrome (HFS) was seen. Conclusions: UFT plus LV with alternating irinotecan and oxaliplatin is an efficacious first-line treatment for patients with ACRC, with minimal alopecia and neurotoxicity and no HFS. No significant financial relationships to disclose.