METHODS: A retrospective cohort design and data from two US healthcare claims repositories were employed. Study population included patients who had non-metastatic cancer of the breast, colon/rectum, lung, or ovaries or non-Hodgkin’s lymphoma (NHL), and who received myelosuppressive chemotherapy regimens with an intermediate/high-risk for FN. For each patient, the first cycle of the first course was characterized in terms of PP-CSF use and FN episodes. Crude incidence proportions for PP-CSF and FN during the first cycle were estimated by calendar quarter (2010-2016); multivariable logistic regression models were used to estimate quarter-specific adjusted mean probabilities of FN by PP-CSF use.RESULTS: Study population totaled 142,730 patients with breast cancer (61%), colorectal cancer (14%), NHL (11%), ovarian cancer (10%), or lung cancer (5%). PP-CSF use increased from 52% in 1Q2010 to 58% in 4Q2016; pegfilgrastim was the most commonly used agent (>96% across quarters). PP-CSF administration on same day as chemotherapy ranged from 8-11% until Q12015, and increased to 64% by Q42016. Adjusted incidence proportions for FN in the first chemotherapy cycle ranged from 2.7% (95%CI: 2.3-3.0) to 3.7% (95%CI: 3.1-4.3) among those who did not receive PP-CSF, and was 2.6% (95%CI: 2.5-2.7) across quarters among those who received PP-CSF.

CONCLUSIONS: Although the use of PP-CSF is commonplace in current US clinical practice, underutilization in cancer patients receiving chemotherapy regimens with an intermediate/high-risk for FN may still be an issue. Use of same-day PP-CSF increased markedly from the end of 2015, although this finding reflects (at least in part) increased uptake of pegfilgrastim delivered via an on-body injector as well as the recent change in clinical practice guidelines. Overall, patients receiving PP-CSF appear to have a lower risk of FN during the first cycle of chemotherapy.