Efficacy and safety of half-dose pegfilgrastim in cancer patients receiving cytotoxic chemotherapy.

Abstract

9110 Background: Pegfilgrastim reduces neutropenia risk in patients (pts) on cytotoxic chemotherapy. A single 6 mg dose per chemotherapy cycle commonly causes bone pain and leukocytosis. While half-dose pegfilgrastim has been shown to be safe and effective in breast cancer pts, there is no data on half-dose pegfilgrastim in general oncology pts. Methods: We evaluated the efficacy and safety of half-dose pegfilgrastim in general oncology pts on cytotoxic chemotherapy at St Francis Cancer Center. Pts who received at least one dose of 6 mg pegfilgrastim and developed NCI-CTCAE grade 2 or more bone pain and/or leukocytosis (WBC>10,000/ml) were given 3 mg dose pegfilgrastim on their following chemotherapy cycles. Pt demographics, type/number of chemotherapy regimens, efficacy, side effects and complications were evaluated. McNemar’s test, logistic regression analysis and ANOVA were used for statistical analysis. Results: Twenty-six pts (3 males, 23 females, all Caucasian) with median age 55 (range 34-86) received a total of eighty-three 3 mg doses of pegfilgrastim. Cancers treated were breast (N=16), colorectal (N=7), head and neck (N=1), non-Hodgkin lymphoma (N=1) and non-small cell lung cancer (N=1). Chemotherapy received was anthracycline (N=9), taxane (N=7), 5-FU/oxaliplatin (N=7), 5-FU/cisplatin (N=1), gemcitabine/oxaliplatin (N=1), pemetrexed/carboplatin (N=1). No neutropenia or chemotherapy dose modifications occurred on half-dose pegfilgrastim. In the 26 pts we report, bone pain occurred in 23 pts at 6 mg and 14 pts at 3 mg dose. Leukocytosis occurred in 23 pts at 6 mg and only 2 pts at 3 mg dose (McNemar’s test, P<0.01). While older age and full-dose pegfilgrastim were predictive of bone pain, more than one line of chemotherapy and half-dose pegfilgrastim were predictive of lack of leukocytosis (logistic regression analysis/ANOVA, P<0.01). Conclusions: Half-dose pegfilgrastim in general oncology pts receiving cytotoxic chemotherapy seems to be safe and effective with less bone pain and leukocytosis without resultant neutropenia or need for chemo modification. Larger prospective studies of half-dose pegfilgrastim in this setting are needed to further understand the feasibility of this approach.