Outcomes Are Similar Following Allogeneic Hematopoietic Stem Cell Transplant for Newly Diagnosed Patients Who Received Venetoclax + Azacitidine Versus Intensive Chemotherapy
Authors: Winters Amanda C. , Bosma Grace , Abbott Diana , Minhajuddin Mohd , Jordan Craig T , Pollyea Daniel A. , Gutman Jonathan A. 
Published: November 2021

Abstract
Background: Venetoclax-based therapy regimens are now FDA-approved for treatment of acute myeloid leukemia (AML) in older patients or those unfit to tolerate intensive chemotherapy (IC). Remission rates are high at 60-70% but relapses do frequently occur. Outcomes for newly-diagnosed patients who receive venetoclax-based therapies and proceed to a potentially curative allogeneic stem cell transplant (SCT) have largely been unreported. In the current study we compare outcomes of patients who received SCT following either IC or venetoclax + azacitidine (ven/aza) at the University of Colorado Hospital.
Methods: Patients 18 years or older who received SCT in first remission of AML between 2010-2020 were included in the analysis. Patients were stratified into the IC arm if they initially received a backbone of cytarabine and an anthracycline; some patients in this cohort received IC in combination with other targeted agents. Patients who received ven/aza as first-line therapy followed by SCT were grouped in a separate cohort. Demographic and clinical information - including flow cytometry-based (MCF) MRD - was extracted from the electronic medical record.
Comparisons of demographic and clinical variables between IC and ven/aza groups were made with t-test, Chi-squared, or Fisher's exact test depending on the nature of the variable. Relapse-free (RFS) and overall (OS) survival were calculated from the day of SCT to the respective endpoint or last documented follow-up using log-rank statistics. Finally, a Cox proportional hazards model was used to assess the interplay between variables pre- and post-SCT. P-values &lt;0.05 were considered significant.
Results: We identified 179 patients who received SCT for AML in first remission. Of these patients, 151 received IC and 28 received ven/aza prior to SCT. Patients in the ven/aza group had higher median age than those in the IC group, as well as a higher proportion with adverse ELN genetic risk scoring. Patients in the ven/aza group received less intensive conditioning regimens. Sex, rates of MCF MRD negativity pre-BMT, incidence of severe acute or chronic GVHD, and causes of death were not significantly different between the two groups. There was no difference between the two groups in post-transplant RFS or OS (Figure 1). In a multivariate Cox model of pre-transplant variables predicting OS, the only factor that achieved significance was pre-SCT MCF MRD; the induction regimen was not a multivariate factor. Negative MCF MRD going into SCT was associated with decreased likelihood of relapse, GVHD, and death, respectively.
Conclusions: In our cohort of AML patients receiving SCT, we found that ven/aza as a pre-transplant therapy yielded equivalent post-transplant outcomes compared to IC, in a population of older age and with higher ELN genetic risk. MCF MRD pre-SCT was confirmed as a key prognostic factor for post-SCT outcome. These findings support ongoing use of ven/aza as a first line therapy for elderly patients with AML as well as its exploration as a candidate therapy for younger patients.
Figure 1 Figure 1.

Disclosures
Pollyea: Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other; Aprea: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kiadis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Syndax: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Agios: Other, Research Funding; Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Teva: Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Curis, Servier: Other; Pfizer: Research Funding; Syros: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Other: advisory board; Foghorn: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Other: advisory board; Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: advisory board.