Researchers added oxaliplatin to a standard regimen of leucovorin-modulated 5-fluorouracil (5-FU) and found that it resulted in an absolute increase of 4.9% in the number of patients who were disease-free at 3 years, said Norman Wolmark, MD, chairman and principal investigator, National Surgical Adjuvant Breast and Bowel Project (NSABP), Pittsburgh, Pennsylvania.

"The data show a highly significant advantage in favor of adding oxaliplatin to leucovorin-modulated 5-FU," Dr. Wolmark said.

The NSABP C-07 study randomized 2407 patients with stage II and III colorectal cancer to either leucovorin-modulated 5-FU (FULV) or FULV plus oxaliplatin (FLOX).

The 3-year point estimates show that 71.6% of FULV patients were disease-free, compared with 76.5% of those given FLOX (P = .004). The difference translates into a 21% reduction in the risk of recurrence, Dr. Wolmark said.

The results, he added, "confirm and extend" the findings of a French study -- Oxaliplatin, Fluorouracil, and Leucovorin as Adjuvant Treatment for Colon Cancer (MOSAIC). Both showed a benefit of about 5%, but the US trial used "a very different regimen."

The NSABP C-07 trial employed a less burdensome regimen, giving FULV as a 2-hour bolus, rather than as a prolonged infusion. Oxaliplatin was added to the regimen at weeks 1, 3, and 5 of an 8-week cycle, which was repeated 3 times.

"This shows that the benefit of oxaliplatin is schedule-independent," Dr. Wolmark said.

The US study also gave a lower cumulative dose of oxaliplatin, which reduced the incidence of grade 3 neurological problems. In the MOSAIC study, 12% of oxaliplatin patients reported neurological side effects, compared with 8% in the C-07 trial.

Other adverse effects were roughly comparable between the arms of the study, he says, although diarrhea and dehydration were slightly more common in the oxaliplatin arm (4.7% vs 2.8%). Dr. Wolmark added that 1 year after the end of treatment, the rate had dropped to a "very acceptable" rate of 0.5%.


[Presentation title: A Phase III Trial Comparing FULV to FULV + Oxaliplatin in Stage II or III Carcinoma of the Colon: Results of NSABP Protocol C-07. Abstract LBA3500]

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