Real-World Treatment Patterns and Overall Survival Among Newly Diagnosed and Relapsed/Refractory Acute Myeloid Leukemia (AML) Patients: A Retrospective Cohort Study Using Claims Data
Authors: Huntington Scott F. , Chang Hsien-Yen , Fu Alex Z. , Loefgren Christina , Lu Xiaoxiao 
Published: December 2023

Introduction: Acute myeloid leukemia (AML) is a malignant disorder of the bone marrow, characterized by abnormal clonal proliferation and differentiation arrest of myeloid progenitor cells. Prognosis is generally poor and worsens with age. While curative therapies are available, they are often unavailable to older patients and those with significant comorbidities due to high morbidity and mortality associated with intensive therapy. Since 2017, seven new systemic therapies have been approved for various AML patient populations, including those unfit for intensive therapy. This study aims to characterize first-line (1L) and second-line (2L) treatment patterns and outcomes in newly diagnosed (ND) and relapsed/refractory (R/R) AML patients, in the context of these newly available therapies.

Methods: A large US administrative claims database (Optum) was used to identify ND AML patients between January 1, 2016, and August 31, 2022. The “ND index date” was defined as the first date a non-R/R AML diagnosis code was observed. To confirm that the initial AML diagnosis represented a true case of AML, ≥2 subsequent AML diagnoses within 60 days post-index were required. A washout period of 12 months was used to confirm no previous AML diagnosis. ND patients were required to have continuous enrollment from 1 year prior to the index until ≥30 days after the index date or death, whichever was earlier. A subgroup of R/R patients was then identified: all ND cohort members who 1) had an R/R AML diagnosis code, 2) had continuous enrollment between ND index date and ≥30 days after the RR index date, and 3) did not receive 1L hematopoietic stem cell transplant (HSCT) after the ND index date were eligible for inclusion. In this subgroup, the “RR index date” was defined as the first date an R/R AML diagnosis code was observed.

Demographic characteristics, clinical characteristics, and treatment patterns over time were reported descriptively. Treatment regimens over time were described using the following classification: HSCT, intensive chemotherapy without targeted agents, intensive chemotherapy with targeted agents, hypomethylating agent (HMA) therapy only, other targeted therapy, Venetoclax-based therapy, unspecified/other treatment, no treatment/supportive care only. Overall survival (OS) was described using the Kaplan-Meier estimator. All analyses were stratified by line of therapy and transplant status.

Results: We identified 5,135 ND AML patients and 934 R/R AML patients (ND cohort: mean age at initial AML diagnosis 73.5 years, mean follow-up time 6.1 months). ND patients receiving transplant in 1L tended to be younger and had fewer comorbidities than those not receiving transplant ( Table 1). Over the entire study period, 61% of ND patients and 69% of R/R patients received some treatment for AML; older patients were more likely to receive supportive care only. In 1L, Venetoclax-based and intensive chemotherapy without targeted agents were the most common treatment regimens (21% and 17% of all ND patients). In 2L, Venetoclax-based and HMA-only therapies were most common (17% and 16% of all R/R patients). Increases in the use of novel therapies (Venetoclax, intensive chemotherapy with targeted agents, or other targeted therapies) were observed in both 1L and 2L over the study period ( Figure 1). 1-year OS among ND patients was 32% in non-transplant recipients, and 84% in transplant recipients; among R/R patients, 1-year OS from RR index date was 21% in non-transplant recipients and 81% in transplant recipients.

Conclusions: The findings from the present study indicate substantial disease burden and ongoing unmet need among ND and R/R AML patients in the USA. While treatment patterns for AML have changed significantly following the advent of novel therapies (with 41% of 1L patients and 31% of 2L patients being treated with novel therapies in 2022), OS remained low. Notably, around 1/3 of patients with RR AML did not receive active treatment; these patients tended to be older and were more frail. Increasing off-label use of Venetoclax in 2L further underscores high unmet need for patients who require more effective treatment options.