Pegfilgrastim Benefits Elderly Breast Cancer Patients on Chemo

BOSTON—Pegfilgrastim (Neu-lasta), the longer-lasting analog of the colony-stimulating factor filgrastim (Neupogen), is safe for elderly breast cancer patients receiving myelosuppressive chemotherapy and protects against febrile neutropenia, according to a poster presented at the third meeting of the International Society of Geriatric Oncology (SIOG abstract P-23).

Richard S. Harms, PharmD, RPh, manager of oncology professional services at Amgen Inc., Thousand Oaks, California, presented the analysis on behalf of the authors, four researchers from the Pegfilgrastim Study Group.

The investigators retrospectively analyzed pooled data for elderly patients from two key phase III trials of pegfilgrastim. About 13% of patients in these studies were over age 65. The results established that pegfilgrastim once per chemotherapy cycle is as safe and effective as daily filgrastim. Results for patients in the 65-and-over age group were comparable to those of younger patients, and the researchers concluded that the relative risk of neutropenic events was similar.

The risk of febrile neutropenia was significantly lower among the elderly patients given pegfilgrastim, occurring in 15% of patients on pegfilgrastim vs 22% of those on filgrastim. The relative risks of hospitalization and use of an intravenous anti-infective agent also were lower for patients given pegfilgrastim, but not significantly.

Dr. Harms cautioned that the benefit of pegfilgrastim over filgrastim could not be stated conclusively, because the original trials were not designed to establish the superiority of one form of the colony-stimulating factor over the other—only that the two were equivalent.