Preliminary results from a phase II study of infusional 5-FU, leucovorin, and irinotecan (FOLFIRI) plus bevacizumab as first-line treatment for metastatic colorectal cancer (mCRC)
3579 Background: Irinotecan (I) plus bolus 5-FU (F) and leucovorin (L) comprise the IFL regimen, a very active treatment in mCRC when combined with bevacizumab (B). The response rate (RR) for IFL-B given as first-line treatment is 45%, with a median progression-free survival (PFS) of 10.6 months and a median survival of 20.3 months. The IFL regimen is now considered inferior to infusional 5-FU regimens, such as FOLFIRI, which have less toxicity and improved efficacy. Methods: We designed a 43 patient (pt), single-arm phase II trial of FOLFIRI-B with B (5mg/kg), I (180mg/m2), bolus of F (400mg/m2) and L (400mg/m2) followed by a 46-hour infusion of F (2400mg/m2), with a primary endpoint of progression-free survival (PFS). Chemotherapy naïve mCRC patients (pts) with adequate organ function and performance status 0–2 received B alone on Day minus 14, starting FOLFIRI + B on Day 1. DCE-MRI and laboratory correlates were completed before and after B alone and cycle 1. Once cycle is equivalent to two weeks. Results: 21 pts, median age 59 y/o (range 26–75), M:F = 15:6, 4 with prior F in adjuvant setting, have been enrolled to date. 20 pts are evaluable for response. One pt is too early. A total of 215 cycles have been administered (median 11). Median PFS has not been reached after a median follow-up of 8 months. By intent-to-treat analysis, there were 14 PRs (70%), and 5 (25%) pts with stable disease observed (including 1 unconfirmed PR). PRs were observed from 9 to 35 weeks after the first cycle (median: 18 weeks). 9 pts remain on treatment (1–12 months); 12 pts are off study (3 for progressive disease, 1 withdrew, 4 sent for curative surgery, 2 for toxicity, 2 sent for surgery unrelated to cancer). Toxicity included 10 cases of grade 3 neutropenia, including 1 febrile neutropenia, 4 venous thrombi, and 6 cases of hypertension requiring medication change. One pt included in the analysis developed peritonitis, considered a possible microperforation, after B alone and never received FOLFIRI. No ≥ grade 3 diarrhea was observed. Analysis of correlative studies will be presented at a later date. Conclusion: Our preliminary results indicate that FOLFIRI-B is well tolerated and an excellent choice as a first-line treatment for mCRC. [Table: see text]