Real-world (RW) antiemetic use and its association with duration of oral azacitidine (Oral-AZA) maintenance in patients (pts) with acute myeloid leukemia (AML) in the United States (US).
Authors: Qiu Ying , Chen Jiafan , Tang Derek , Byrne Clare , Singh Nisha , Vergara Sara 
Published: June 2024

e23259 Background : Oral-AZA was approved in the US in Sep 2020 for maintenance treatment of transplant-ineligible pts with AML in remission following intensive chemotherapy. Approval was based on the QUAZAR trial (NCT01757535), which showed that Oral-AZA was associated with longer survival outcomes than placebo in this pt population. Both the prescribing information and clinical guidelines recommend antiemetic prophylaxis with Oral-AZA for at least the first 2 cycles to prevent the most common adverse events, nausea and vomiting. However, the extent to which antiemetics are being used with Oral-AZA in the real world is not yet well understood. This study aimed to examine the use of antiemetics among pts with AML receiving Oral-AZA in RW clinical practice and to determine whether this has any association with duration of therapy (DoT). Methods : This was a retrospective, observational study using Flatiron Health electronic health record data from Jan 2014 to Apr 2023. Eligible pts were ≥18 years and had a diagnosis of AML and ≥1 order for Oral-AZA on or after Sep 1, 2020. The index date was date of Oral-AZA initiation. Pts were followed until death, loss to follow-up, or the end of the study. Pt characteristics were assessed on the index date; antiemetic use was assessed at index and over the follow-up period. For each pt, each 28-day cycle of Oral-AZA was denoted as “covered” or “not covered” by antiemetics according to whether the pt had ≥14 days of antiemetics available during the cycle. Total DoT was measured for Oral-AZA using cumulative incidence curves and compared between pts with their first 2 cycles covered and those without. Results: 189 pts with AML were included. Mean age was 66 years, 52% were female, 56% had evidence of prior cytarabine use, and 10% had a prior stem cell transplant. 152 pts had ≥2 cycles of Oral-AZA. Overall, less than half of pts (48%) had a claim for an antiemetic on the index date. 16% never initiated an antiemetic between index and the end of follow-up; in the remaining 84%, the mean time from the index date to antiemetic initiation was 57 days and 29% had a time to antiemetic initiation of > 56 days. Only 9% (14/152) of pts had both their first 2 Oral-AZA cycles covered by antiemetics. Overall, pts had a median of 5 Oral-AZA cycles. Pts with antiemetic coverage of their first 2 cycles had a median of 8.5 Oral-AZA cycles versus 6 in those without. The median DoT was longer for pts with antiemetic coverage of cycles 1 and 2 than those without (258 days vs 154 days). Conclusions: These findings suggest that antiemetics are not currently widely utilized with Oral-AZA in RW US clinical practice. This may reduce DoT and could potentially impact the likelihood of observing RW efficacy outcomes like those in the QUAZAR trial. Further studies are required to examine the association between guideline-recommended antiemetic use and clinical outcomes.