New phase III study data indicate that addition of oxaliplatin to the combination regimen irinotecan/5-fluorouracil/leucovorin improves survival of patients with advanced colorectal cancer, reducing tumor size and prolonging time to progression of disease, according to a presentation at the 2006 Gastrointestinal Cancers Symposium.

“First-line combination treatment with irinotecan, 5-FU/leucovorin, and oxaliplatin, called FOLFOXIRI, increases the chance of shrinking tumors?enabling surgeons to remove metastases?slows tumor growth, and helps patients live longer,” said Alfredo Falcone, MD, Professor of Medical Oncology at the University of Pisa, Chairman of Oncology at Livorno Hospital, and lead author of the study. “These findings are very promising, and indicate that this new triplet combination is superior to a standard doublet such as FOLFIRI. Further studies with FOLFOXIRI, particularly in combination with new targeted agents, are warranted.”

The chemotherapy regimen called FOLFOX?combination oxaliplatin, 5-fluorouracil, and leucovorin, has recently become the new standard of care for patients with metastatic disease. Irinotecan in combination with infused 5-FU/leucovorin (FOLFIRI) has also been a standard therapy for metastatic colorectal cancer.

In the current study, Falcone and his Italian colleagues compared the incidence of tumor shrinkage, progression-free survival, and overall survival in 122 patients with previously untreated metastatic colorectal cancer who received irinotecan, 5-FU, and leucovorin (the FOLFIRI group) and 122 patients who received these three drugs plus oxaliplatin (the FOLFOXIRI group). Patients were enrolled starting in November 2001 and were followed through April 2005.

Patients in the FOLFOXIRI group lived longer (22.6 months) than those in the FOLFIRI group (16.7 months). After a median follow-up of 14 months, progression-free survival was longer in the FOLFOXIRI group (9.8 months) than in the FOLFIRI group (6.8 months). More patients in the FOLFOXIRI group (66 percent) experienced complete tumor disappearance or partial tumor shrinkage than in the FOLFIRI group (41 percent).

Although side effects were more common in the FOLFOXIRI group (such as diarrhea, vomiting, neuropathy, and low white blood cell counts), they were generally considered to be manageable and tolerable.