In clinical trials, Avastin has demonstrated efficacy across a range of patient types with colorectal cancers with IV 5-FU–containing chemotherapy regimens. In particular, Avastin has demonstrated significant clinical benefits with combination chemotherapy regimens—including IFL (Study 2107) and FOLFOX4 (Study E3200)—as well as with IV 5-FU/LV alone (studies 2107, 2192, and 0780). Irinotecan is a drug that is standard in second (or later) lines of treatment for colorectal cancer, usually as the Fofiri combination . A phase III trial showed that it as effective as Foflfx. The Avastin is FDA approved with 5 FU based chemo, which includes both Folfox and Folfiri. It is appropriate to offer irinotecan monotherapy as second-line treatment to patients following failure of first-line treatment with: Infusional 5-fluorouracil/leucovorin and oxaliplatin (FOLFOX), Bolus or infusional 5-fluorouracil/leucovorin (Mayo or de Gramont schedule) or it can be used first line. Oral capecitabine with Avasti n is likewise approved for colon cancer in combination with 5FU based therapy, for first or subsequent lines of therapy. The combination of Avastin and irinotecan without 5FU has been used in a phase III trial but was dropped after safety was demonstrated in order to focus on other arms. The NCCN and Canadian guidelines mildly suggest that these two drugs can be used together. Certainly in advanced setting, this would be an appropriate approach in Avastin naive patients. Avastin is FDA indicated for the first- or second-line treatment of patients with metastatic carcinoma of the colon or rectum in combination with intravenous 5-fluorouracil–based chemotherapy.
GasFigueredo A, Moore M, Germond C, Kocha W, Maroun J, Zwaal C. Use of irinotecan in the second-line treatment of metastatic colorectal carcinoma. Toronto (ON): Cancer Care Ontario (CCO); 2004 Jul. 21 p. (Practice guideline report; no. 2-16). [40 references] nccn.org, colorectal http://www.cancercare.on.ca/pdf/pebc2-25s.pdf