G-CSF Slashes Irinotecan-Related Neutropenia and Diarrhea

ATHENS—Early results from a phase III multicenter study suggest that the major dose-limiting side effects of irinotecan (Camptosar) in colon cancer—neutropenia and delayed diarrhea developing 24 hours after administration—can be controlled by the use of G-CSF (Neupogen).

This preliminary analysis, presented at the European Society for Medical Oncology Congress, was based on data from 361 patients, two-thirds of whom had liver metastases and 80% of whom had received prior chemotherapy. Study participants were randomized to receive irinotecan, 350 mg/m² as a 30-minute IV infusion every 3 weeks, followed by 9 days of treatment with G-CSF, 150 g/m²/day, or irinotecan alone.

G-CSF treatment halved the incidence of grade 3-4 neutropenia and delayed diarrhea, as well as the incidence of concomitant severe neutropenia and diarrhea, reported investigator Paris Kosmidis, MD, of Hygeia Hospital, Athens. As a result, Dr. Kosmidis said, patients receiving growth factor were able to receive more of their chemotherapy courses on time. The relative dose intensity achieved, the rate of discontinuation due to adverse effects, and the frequency of febrile episodes were similar in both groups, however.

Irinotecan produced responses in 10% of patients and stabilized disease progression in more than half. “This is consistent with literature results for heavily pretreated patients with extensive disease,” he said. When irinotecan is combined with G-CSF, he said, “it seems there are fewer side effects, better quality of life, and less risk of severe dehydration.” Still to be explored are cost effectiveness of G-CSF and possible impact on survival.