Risk of chemotherapy-induced XXXX with early discontinuation of pegfilgrastim prophylaxis in US clinical practice.

@entity5 @entity1 @entity1398 @entity1893
PURPOSE: Accumulating evidence suggests that not all @entity5 chemotherapy @entity1 who receive first-cycle pegfilgrastim prophylaxis continue to receive it in subsequent cycles and that these @entity1 may be subsequently at higher risk of @entity1398 ( @entity1398 ). Additional evidence from US clinical practice is warranted. METHODS: Data from two US private healthcare claims repositories were employed. The source population comprised adults who received "intermediate-risk" or "high-risk" chemotherapy regimens for solid @entity5 or @entity1893 and first-cycle pegfilgrastim prophylaxis. From the source population, all @entity1 who did not receive second-cycle pegfilgrastim prophylaxis ("comparison @entity1 ") were matched (1:1) to those who received it ("pegfilgrastim @entity1 ") based on @entity5 , regimen, and propensity score. Odds ratios (OR) for @entity1398 -broad and narrow definitions-during the second chemotherapy cycle were estimated for comparison @entity1 versus pegfilgrastim @entity1 using generalized estimating equations. RESULTS: A total of 2245 comparison @entity1 (5.3  % of source population) were matched to pegfilgrastim @entity1 ; cohorts were well-balanced on baseline characteristics. Second-cycle @entity1398 incidence proportions for comparison and pegfilgrastim @entity1 were 3.8 versus 2.2  % based on broad definition and 2.6 versus 0.8  % based on narrow definition; corresponding OR were 1.7 (95  % CI 1.2-2.5, p   =   0.002) and 3.5 (95  % CI 2.0-6.0, p   <   0.001). Results were similar within @entity5 /regimen-subgroups and were robust when using alternative methods for confounding adjustment. CONCLUSIONS: In this retrospective evaluation of @entity5 chemotherapy @entity1 who received first-cycle pegfilgrastim prophylaxis in US clinical practice, a clinically relevant minority did not receive second-cycle prophylaxis. Second-cycle @entity1398 odds among this subset were significantly higher than they were among those who continued prophylaxis.
