P587: real-world characteristics and use of antiemetic therapies among patients with acute myeloid leukemia treated with oral azacitidine maintenance therapy

Background: Oral azacitidine was approved in the USA in September 2020 for maintenance treatment of patients with acute myeloid leukemia (AML) with a complete response or complete response with incomplete blood count recovery following intensive chemotherapy. Approval was based on the QUAZAR trial (NCT01757535), which demonstrated that oral azacitidine was associated with longer overall and relapse-free survival than placebo in this patient group. Nausea and vomiting were the most common side effects observed in the QUAZAR trial; thus, both the prescribing information and clinical treatment guidelines recommend antiemetic prophylaxis with oral azacitidine. To date, no real-world study of patients receiving oral azacitidine has been published, so it is not yet known whether this recommendation is being put into practice. Aims: To describe the patient characteristics and use of antiemetic therapies among real-world patients with AML receiving oral azacitidine in the USA. Methods: This was a retrospective, observational study using Symphony Health Solutions open claims data from September 2018 to December 2022. Eligible patients were ≥18 years of age and had a diagnosis of AML and ≥1 claim for oral azacitidine on or after September 1, 2020. The index date was the date of oral azacitidine initiation; patients had to have evidence of claims activity in the 12 months pre-index, and ≥1 claim post-index. Patients were followed until their last claim activity or the end of the study period, whichever occurred first. Patient characteristics were assessed at index; antiemetic use was assessed at index and over the follow-up period. “Optimal” antiemetic use was defined as having an antiemetic claim on or before initiation of oral azacitidine with antiemetic coverage throughout the azacitidine treatment cycle (number of days’ supply of the antiemetic was greater than or equal to the number of days in the azacitidine treatment cycle). A less restrictive definition of antiemetic coverage was also considered (any antiemetic claim within 28 days of the index date, allowing for capture of reactive as well as proactive use). All analyses were descriptive. Results: A total of 514 eligible patients were included in the study. The mean age was 62.5 years, 51.6% were male, and 41.4% were from the South. The mean Charlson Comorbidity Index (excluding malignancy) score was 0.9 (standard deviation, 1.4). The most common comorbidities were diabetes (28.2%), chronic pulmonary disease (15.4%), congestive heart failure (14.0%), and peripheral vascular disease (10.3%). Overall, only 46 (8.9%) patients had a claim for an antiemetic on the index date. Over the follow-up period, according to the “optimal” definition, only 2.6% of patients had their first oral azacitidine cycle covered by antiemetics, and only 1.6% had both their first and second cycles covered. When applying the less restrictive antiemetic coverage definition, 47.9% of patients had their first cycle covered and 32.8% had both their first and second cycles covered. Conclusion: These results indicate that for most patients the use of antiemetic therapies with oral azacitidine in real-world clinical practice may not align with the prescribing information or treatment guidelines. When there was evidence of antiemetic use, it appeared to have been more often reactive than proactive. Given that oral azacitidine can be associated with nausea and vomiting, a better understanding of the importance of using prophylactic antiemetics with this novel therapy may lead to better patient outcomes over time. Keywords: Real world data, Azacitidine, CINV prophylaxis, antiemetics