Drug formulary review process for sargramostim and filgrastim: focus on analysis of adverse drug reactions.

Selection of a drug for formulary inclusion involves evaluation of safety, efficacy, and cost. The colony-stimulating factors (CSFs) sargramostim and filgrastim have a broad range of potential indications and represent a costly formulary addition when acquisition price alone is considered; their comparative safety is unclear. These factors suggest that the CSFs should be closely scrutinized prior to formulary addition. In the absence of direct comparative studies, an assessment of the safety of CSFs involves evaluation of information provided in the product circular, official drug compendia, adverse biologic reports submitted to the United States Food and Drug Administration, and data from key clinical trials. Data in the product circulars report on adverse events in small numbers of patients treated for chemotherapy-induced neutropenia (filgrastim) or neutropenia subsequent to bone marrow transplantation (sargramostim). The official compendia and clinical trials include experience with CSFs produced in a variety of expression systems; these data are not limited to sargramostim and filgrastim. Importantly, there was a similar incidence of adverse events in patients who received sargramostim or filgrastim and in those who took placebo reported in the product circulars and the pivotal trials, suggesting that the underlying disease may have an important role in determining the side-effect profile of these agents. Adverse biologic reports represent experience with sargramostim and filgrastim obtained under actual clinical conditions and suggest that the same types of adverse events are seen with sargramostim as with filgrastim. This analysis suggests that a decision to select filgrastim over sargramostim for formulary inclusion based on the safety profile is not appropriate because currently available data are equivocal and that such decisions would more appropriately be based on efficacy and cost.