Real-world evidence evaluating the use of an NK-1 antiemetic in the systemic chemotherapy treatment of metastatic breast cancer.

Abstract

e12599 Background: Severe and persistent nausea and vomiting (n/v) impacts quality of life and may lead to treatment discontinuation. While antiemetics assist with minimizing these effects, newer drugs can be expensive and carry their own side effect profile. Prior research has suggested that neurokinin 1 receptor inhibitor(NK-1) antiemetics are overly prescribed. Using the package insert recommendations for aprepitant, an NK-1, we evaluated the frequency of its prophylactic use to prevent emesis in patients receiving systemic chemotherapy(chemo) with moderate to high emetogenic risk. Methods: Patients were identified from a third-party, administrative claims database. Using medical and pharmacy claims, any female with ICD-9/10 codes for both breast cancer and metastases diagnosed between Jan-2013 and Dec-2017, who initiated systemic chemo and received aprepitant prophylactically were selected. Chemo regimen emetogenic potential was scored using the Hesketh scale and aggregated into two cohorts: low risk (grade 1-2 = none- < 30%), and moderate-high risk (grade 3-5: > 30- > 60%). If patients received combination chemo, the assigned risk level was the highest risk of any individual agent. The frequency of NK-1 use for each risk cohort was calculated per line of therapy independent of the previous treatment. Results: 10,342 patients met the selection criteria with 2,868 patients administered moderate-high emetogenic risk chemotherapy regimens. Mean age at initiation of treatment was 61.7 years (SD = 12.12). By line, the aprepitant utilization rate was: 1 line(L) 43% ,2L 27%, 3L 18%, 4L 16%, 5L 11% and 6L 12%. Across all lines of therapy, aprepitant was used prophylactically in 23% of patients treated with high risk chemo regimens and in 2% of patients who had received low risk regimens. Conclusions: Prophylactic use of the NK-1 inhibitor aprepitant was less than 50% in 1L moderate-high emetogenic risk chemotherapy and declined with consecutive lines of treatment. NK-1 use with low risk regimens was minimal. Further research is needed to understand the pattern of use and clinical outcomes between moderate-high emetogenic risk patients who do and don't receive NK-1 antiemetic supportive care.