Incidence of febrile neutropenia and effectiveness of pegfilgrastim prophylaxis in patients with advanced-stage solid tumors receiving chemotherapy.
e20564 Background: Advanced disease stage has been identified as an independent risk factor for the development of febrile neutropenia (FN), which continues to be associated with substantial morbidity. We report here results from two clinical trials on the impact of pegfilgrastim (PEG) in patients with advanced stage solid tumors. Methods: Patients were pooled from two placebo-controlled trials: a) a phase III trial of 928 patients with breast cancer, randomized to placebo or PEG 6 mg on day 2 of each 21-day cycle (Vogel CL, et al. JCO 23:1178-84, 2005); and b) a phase II trial of 241 patients with colorectal cancer (CRC), randomized to placebo or PEG 6 mg on day 4 of each 14-day cycle (Hecht JR et al. Clin CRC 9:95-101, 2010). Patients were grouped by disease stage at baseline: advanced (stage III, IIIA, IIIB, IV) or limited (stage I, II, IIA, IIB). Grade 3/4FN was defined as a temperature of ≥ 38.2°C and an ANC of <1.0 x 109/L. The Cochran-Mantel-Haenszel test was used to evaluate the association between PEG and grade 3/4 FN, odds ratio (OR) for FN was estimated by logistic regression, and a trend in the number of FN events per patient was estimated using a Cochran-Armitage test. Results: Characteristics of the 982 patients with advanced stage cancer are shown in the table. PEG was associated with significantly fewer grade 3/4 FN events (p < 0.001), with OR for PEG vs placebo of 0.12 (95% CI: 0.07, 0.22). The percentage of patients with 0, 1, and ≥ 2 FN events was 97%, 3%, and 0% with PEG and 81%, 18%, and 0.4% with placebo, and PEG significantly reduced the number of FN events (p< 0.001). Conclusions: Patients with advanced stage cancer are at considerable risk for developing FN, and PEG prophylaxis reduced that risk. Assessment of FN risk is essential in the advanced/metastatic treatment setting. [Table: see text]