Hypomethylating agent with venetoclax versus hypomethylating agent alone in frontline management of myelodysplastic syndrome - impact of subgroups on clinical outcomes

Abstract Background: Hypomethylating agent (HMA) with venetoclax (VEN) is used in clinical practice for frontline management of patients with myelodysplastic syndrome (MDS) based on encouraging data from phase 1 clinical trial (Garcia JS et al. Blood 2025). While the randomized clinical trial (VERONA-NCT04401748) did not show a survival benefit of azacitidine-VEN, the study had important differences such as exclusion of therapy related MDS and being conducted in several non-academic US centers. To better understand the impact of this regimen and its effects in subgroups, we conducted a real-world analysis of frontline MDS patients treated mainly at academic medical centers with HMA-VEN and compared to HMA monotherapy. Methods: This is a multicenter retrospective study of 19 US academic medical centers. We included contemporary cohorts of adults (age≥18 years) with MDS (intermediate, high or very high risk by IPSS-R) who were treated outside of clinical trials with either upfront combination of HMA-VEN or HMA monotherapy. Data on patient-related, disease-related and treatment-related variables were collected through chart review. Descriptive statistics were used for baseline characteristics. Overall survival (OS) and event free survival (EFS: progression, leukemic transformation, death as events) analysis was conducted using Kaplan-Meier method. Determinants of outcomes were analyzed using multivariable regression models. All analyses were conducted at a significance level of p<0.05. Results: Among 1198 patients with intermediate, high or very-high risk MDS, 313 patients received upfront VEN in combination with HMA [HMA-VEN] and 885 patients received HMA monotherapy. Median age was 70 (63-76) years and majority of patients had MDS with excess blasts-1 (34% overall, HMA-VEN=26%, HMA=37%) or MDS with excess-blasts-2 (41% overall, HMA-VEN=60%, HMA=34%). Disease risk by IPSS-R was intermediate (29% overall, HMA-VEN=18%, HMA=33%), high (30% overall, HMA-VEN=31%, HMA=30%) or very-high risk (41% overall, HMA-VEN=51%, HMA=37%, p<0.001). Therapy related MDS (t-MDS) was seen in 27% of patients (HMA-VEN=33%, HMA=25%, p=0.004), 34% had TP53 mutation (HMA-VEN=40%, HMA=32%, p=0.005) and 33% underwent allogeneic hematopoietic stem cell transplantation (AHSCT) (HMA-VEN=42%, HMA=30%, p<0.001). The most common mutations detected at baseline included TP53 (34%), ASXL1 (22%), DNMT3A (16%), RUNX1 (16%), TET2 (14%), SRSF2 (13%), and U2AF1 (11%). The response rate by IWG 2006 criteria was significantly higher with HMA-VEN than HMA monotherapy (overall 81% vs 39%, CR: 17% vs 9.6%; marrow CR: 56% vs 14%, p<0.001). In multivariable analysis accounting for upfront treatment, AHSCT, genomic mutations, baseline bone marrow blasts and t-MDS, patients treated with HMA-VEN in the upfront setting had significantly improved EFS (median EFS 10.7 vs. 7.8 mon, HR 0.83, 95%CI 0.72-0.96, p=0.01) and OS (median OS 22.4 vs. 18.1 mon, HR 0.79, 95%CI 0.64-0.97, p=0.02). In addition, TP53 mutation status (OS: HR 1.88, 95% CI 1.57-2.26, p<0.001, EFS: HR 1.43, 95% CI 1.23-1.65, p<0.001), subsequent AHSCT (OS: HR 0.34, 95% CI 0.27-0.41, p<0.001; EFS: HR 0.47, 95% CI 0.40-0.54, p<0.001), and therapy related MDS (OS: HR 1.20, 95% CI 1.00-1.44, p=0.04, EFS: HR 1.10, 95% CI 0.96-1.27, p=0.2) were significant predictors on multivariable analysis. When separately investigated in subgroups, an OS benefit of HMA-VEN over HMA was seen in patients undergoing subsequent AHSCT (median OS 40.6 vs. 30 mon, p=0.05), bone marrow blast 10-19% (median OS 25.1 vs. 17.4 mon, P=0.01), de novo MDS (median OS 30 vs. 20.1 mon, P=0.003) and absence of TP53 mutation (median OS 34.9 mon vs. 23.1 mon, p=0.004). The benefit of HMA-VEN over HMA was also seen across molecular mutations including presence of ASXL1 mutation (median OS 35.2 vs 20.9 mon, p=0.03). Conclusions: In this large multicenter retrospective analysis from US academic medical centers, we found that HMA-VEN therapy significantly improved OS in certain subsets of high risk MDS including patients with 10-19% blasts, denovo MDS, subsequent AHSCT and those without TP53 mutation. While our analysis is limited by its retrospective design, prospectively exploring subgroups of MDS patients who could benefit from HMA-VEN therapy is needed.