Alternating Venetoclax Triplets Extend Survival in Older AML Patients

A phase 2 trial shows a 45% five-year survival rate and high rates of deep molecular remission using an alternating low-intensity regimen.

For Doctors in a Hurry

Researchers evaluated an alternating low intensity regimen to improve survival outcomes for older or unfit patients with newly diagnosed acute myeloid leukemia.
This phase II trial enrolled 190 patients with a median age of 68 years, including 64 percent with adverse genetic risk.
The complete remission rate was 84 percent, and the median overall survival reached 52 months.
The authors concluded that this combination is safe, with low eight week mortality rates of 3 percent.
These findings suggest the regimen effectively bridges older patients to stem cell transplantation, which 44 percent of responders successfully achieved.

Optimizing Low-Intensity Induction in Older Acute Myeloid Leukemia

The management of acute myeloid leukemia in older adults remains a significant clinical challenge, as the median age at diagnosis is approximately 68 to 70 years [1]. While the combination of venetoclax and hypomethylating agents has become a standard for patients ineligible for intensive chemotherapy, real-world median overall survival often falls short of the benchmarks set in pivotal clinical trials [2]. A critical barrier to long-term survival in this population is the persistence of measurable residual disease (MRD), a threshold of less than one leukemic cell per 1,000 leukocytes that serves as a potent predictor of hematologic relapse [3, 4]. Current low-intensity regimens often fail to achieve MRD negativity in more than 30% to 40% of patients, particularly in molecular subtypes with inherent resistance to BCL-2 inhibition [4, 5]. Consequently, clinicians are increasingly investigating intensified combinations and alternating schedules to deepen responses and improve the feasibility of consolidative hematopoietic stem cell transplantation [6, 7]. A recent phase II study evaluates an alternating regimen designed to maximize cytoreduction while maintaining a manageable safety profile in this vulnerable cohort.

Study Population and High-Risk Characteristics

The phase II study investigated an alternating triplet regimen designed to enhance the depth of response in patients who cannot tolerate intensive induction. The researchers evaluated a combination of cladribine plus low-dose cytarabine and venetoclax alternating with azacitidine plus venetoclax. This approach was tested in a cohort of 190 patients with newly diagnosed acute myeloid leukemia who were either older or clinically unfit for standard high-intensity chemotherapy. By alternating these low-intensity backbones, the study sought to maximize antileukemic activity while minimizing the cumulative toxicity often associated with continuous multi-agent therapy. The study population represented a high-risk clinical demographic, with a median age of 68 years (range, 47 to 84 years). A significant portion of the cohort included the very elderly, as 13% of the study participants were aged 75 years or older. When stratified by the European LeukemiaNet 2022 classification (a standardized system used to predict prognosis based on genetic and molecular markers), the majority of the participants fell into difficult-to-treat categories. Specifically, only 16% of patients were classified as favorable risk, while 20% were intermediate risk and 64% were stratified as adverse risk. This high prevalence of adverse-risk genetics provides a rigorous baseline for evaluating the efficacy of the alternating venetoclax regimen in a real-world clinical context.

Deep Remission and Molecular Responses

The efficacy of the alternating triplet regimen was characterized by high rates of clinical response, even within this predominantly adverse-risk cohort. The researchers reported that the overall rate of complete remission (CR) or complete remission with incomplete blood count recovery (CRi) was 84%. This composite remission rate is a critical metric for clinicians, as it encompasses both patients who achieved full hematologic recovery and those who cleared the leukemic blasts but maintained persistent cytopenias. Beyond these morphological responses, the study emphasized the achievement of minimal residual disease (MRD) negativity, defined as the absence of detectable cancer cells below a specific threshold using sensitive laboratory techniques. Achieving this state is often a prerequisite for long-term survival and successful transition to transplantation. In this study, the overall rate of MRD-negative CR/CRi was 75%, suggesting that the majority of responders achieved a deep molecular response. The presence of TP53 mutations typically confers a poor prognosis and resistance to standard therapies in acute myeloid leukemia. However, patients in this trial without these mutations showed particularly robust responses to the alternating venetoclax combinations. Among patients with TP53-wild type AML, the CR/CRi rate reached 91%, indicating a high level of sensitivity to the regimen in the absence of this specific tumor suppressor mutation. Furthermore, the depth of response remained consistent in this subgroup, as the MRD-negative CR/CRi rate among patients with TP53-wild type AML was 77%. These findings demonstrate that the alternating low-intensity approach can induce high rates of deep molecular remission, raising the prospect of improved long-term disease control for patients lacking the highest-risk genetic alterations.

Durable Survival and Transplant Feasibility

The long-term outcomes for the study cohort demonstrate a level of durability often difficult to achieve in older populations with acute myeloid leukemia. The researchers reported that the median overall survival for the entire cohort was 52 months, while the median event-free survival (the time from treatment initiation to treatment failure, relapse, or death) was 50 months. These figures reflect a sustained response to the alternating triplet regimen over several years. Specifically, the 2-year overall survival rate was 60% and the 5-year overall survival rate was 45%. Similarly, the 2-year event-free survival rate was 56%, with a 5-year event-free survival rate of 43%. These data points suggest that nearly half of the patients who are typically considered unfit for intensive chemotherapy can achieve survival extending to the five-year mark when treated with this low-intensity approach. For clinicians, the ability of this regimen to serve as a bridge to definitive therapy is a key finding. Among the patients who responded to the treatment, 44% proceeded to allogeneic hematopoietic stem cell transplantation, a procedure that remains the primary curative option for this disease. The depth of initial response served as a strong predictor for these long-term outcomes. For the subset of patients achieving minimal residual disease (MRD) negative complete remission, the median overall survival was not reached at the time of analysis. Furthermore, these patients who achieved deep molecular remission demonstrated a 2-year overall survival rate of 70%. This correlation underscores the clinical importance of achieving MRD negativity, as it identifies a patient subgroup with a significantly higher probability of prolonged survival and successful transition to curative cellular therapies.

Safety Profile and Hematologic Recovery

The safety of the induction phase is a primary concern when treating older or unfit patients with acute myeloid leukemia, as treatment-related toxicity can often offset therapeutic gains. In this study, the alternating triplet regimen demonstrated a manageable safety profile during the initial treatment window. The researchers reported a 4-week mortality rate of 1%, which suggests that the low-intensity combination of cladribine, cytarabine, and venetoclax is well tolerated by this vulnerable population. This stability continued through the early consolidation phase, with an 8-week mortality rate of 3%. These low early death rates are particularly relevant for clinicians managing patients who might otherwise be at high risk for treatment-related mortality with standard intensive induction protocols. Myelosuppression is an expected consequence of venetoclax-based triplets, yet the recovery times in this trial remained within clinically predictable ranges. The median time to absolute neutrophil count recovery (defined as greater than 1 x 10^9/L) after induction was 27 days. Similarly, the median time to platelet count recovery (defined as greater than 100 x 10^9/L) after induction was 24 days. These recovery intervals are critical for clinicians to monitor, as they dictate the timing of subsequent treatment cycles and the duration of necessary antimicrobial prophylaxis and transfusion support. Regarding the broader toxicity profile, the treatment was generally safe, though high-grade toxicities did occur. The researchers noted that most grade 3 and 4 adverse events were infectious complications, a finding consistent with the myelosuppression observed in this patient population. Monitoring for and aggressively managing these infections remains a cornerstone of care when utilizing this alternating regimen in older adults, ensuring that the high rates of molecular remission translate into the long-term survival outcomes observed in the trial.

Study Info

Cladribine With Low‐Dose Cytarabine and Venetoclax Alternating With Azacitidine and Venetoclax for Newly Diagnosed Acute Myeloid Leukemia

Tapan M. Kadia, Alex Bataller, Alexandre Bazinet, Gautam Borthakur, et al.

Journal American Journal of Hematology

Published April 25, 2026