Real-world effectiveness of intensive chemotherapy with 7&3 versus venetoclax and hypomethylating agent in acute myeloid leukemia

Ven the dose matters: Venetoclax dosing in the frontline treatment of AML

Older/unfit adults with AML have worse outcomes and fewer treatment options than their younger/fit counterparts. In vitro studies have found a synergistic effect of hypomethylating agents (HMA) with venetoclax (VEN) on AML cells and since the phase 3 VIALE-A trial demonstrated a survival benefit, HMA + VEN has become the standard of care in the frontline setting for older/unfit adults with AML. Unfortunately, the standard 28-day cycle of VEN is associated with a high degree of myelosuppression leading to treatment delays and dose modifications. Many small retrospective studies have successfully shown comparable outcomes to VIALE-A with reduced dose/duration of VEN. Furthermore, low dose metronomic dosing of HMA + VEN has shown clinical benefit while minimizing myelotoxicity. Future trials are vital to understand the appropriate dose of VEN in combination with HMA, to evaluate HMA + VEN compared to intensive therapy for younger/fit patients, and to explore its utility in the relapsed/refractory setting.

A systematic review of venetoclax for the treatment of unfit AML patients in real-world: is all that glitters gold?

Acute myeloid leukemia (AML) is an aggressive hematological disease that mainly affects elderly patients. Following the randomized VIALE-A trial, current standard treatment in patients who are not candidates for intensive chemotherapy consists of the combination of venetoclax (VEN), a selective inhibitor of the anti-apoptotic protein BCL-2, with azacitidine (AZA) or decitabine (DEC). We performed a systematic review to critically assess the growing existing evidence regarding the effectiveness of the VEN-based combinations in unfit adult patients with newly diagnosed AML in the real-world setting. Following PRISMA guidelines, a systematic search of published manuscripts and conference abstracts (European Hematology Association and American Society of Hematology) was conducted (updated March 2024). Primary outcomes were composite complete remission (CRc) and median overall survival (mOS). A total of 73 studies fulfilled inclusion criteria, with a median age of 73 years old. The weighted mean mOS was 10.3 months among 7 138 patients, significantly lower than expected according to the VIALE-A trial (14.7 months), while the weighted mean CRc rate was 58.2% among 5 831 patients, slightly lower to that reported in the VIALE-A (66.4%). Early death rates at 30 and 60 days were 5% and 13%, respectively. The weighted mean percentage of subsequent allogeneic transplant was 15.4%. In conclusion, breakthrough mOS reported in the VIALE-A trial using VEN-AZA was not well reproduced in real world for unfit newly diagnosed AML patients, while CRc rates were more consistent. Strategies to optimize patient selection, dosing regimens, and supportive care are crucial to improve outcomes in real-world.

Hypomethylating agents plus venetoclax compared with intensive induction chemotherapy regimens in molecularly defined secondary AML

Molecularly defined secondary acute myeloid leukemia is associated with a prior myeloid neoplasm and confers a worse prognosis. We compared outcomes of molecularly defined secondary AML patients (n = 395) treated with daunorubicin and cytarabine (7 + 3, n = 167), liposomal daunorubicin and cytarabine (CPX-351, n = 66) or hypomethylating agents (HMA) + venetoclax (VEN) (n = 162). Median overall survival (OS) was comparable between treatment groups among patients aged >60 years. In a multivariable model HMA + VEN vs. 7 + 3 was associated with better OS (hazard ratio [HR] 0.64 [95% confidence interval (CI) 0.42-0.98, p = 0.041]), whereas CPX-351 vs. 7 + 3 was not (HR 0.79 [CI 95% 0.50-1.25, p = 0.31]). Allogeneic hematopoietic stem cell transplantation, BCOR and IDH mutations were associated with improved OS; older age, prior myeloid disease, NRAS/KRAS mutations, EZH2 mutation, and monosomal karyotype were associated with worse OS. When analyzed in each treatment separately, the IDH co-mutations benefit was seen with 7 + 3 and the detrimental effect of NRAS/KRAS co-mutations with HMA + VEN and CPX-351. In pairwise comparisons adjusted for age, HMA + VEN was associated with improved OS vs. 7 + 3 in patients with SF3B1 mutation and improved OS vs. CPX-351 in those with RNA splicing factor mutations. In molecularly defined secondary AML treatment with HMA + VEN might be preferred but could further be guided by co-mutations.

Novel therapies upon failure of HMA plus venetoclax

The efficacy and tolerability of the combination of hypomethylating agents with venetoclax (HMA-VEN) in patients with newly diagnosed acute myeloid leukemia has been a practice-changing milestone in the field. However, treatment failure and relapse remain major barriers to prolonged survival. TP53 mutation is a predictor of primary induction failure and portends especially poor outcomes. Prelinical data suggest that VEN resistance stems from these genetic changes, which lead to increases in antiapoptotic proteins such as MCL-1 and BCLXL. For patients who discontinue HMA-VEN for reasons other than disease progression, such as post allotransplantation, infection, and personal preference, rechallenge with HMA-VEN at the time of relapse may be considered. For those who progress on HMA-VEN, clinical trials with novel agents or rational drug combinations are preferred if available. If no trial option is available, fit patients may benefit from intensive chemotherapy. Emerging therapies aim to overcome venetoclax resistance, target interactions that promote leukemogenesis, and harness the immune system to irradicate leukemic blasts and stem cells.