BOSTONPegfilgrastim (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 otheronly that the two were equivalent.