Personalized Venetoclax Dose Adjustment in Unfit Acute Myeloid Leukemia Patients: A Real-Life Case Series Study

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript addresses the role of measurable residual disease (MRD) monitoring using WT1 expression to guide venetoclax dose adjustment in unfit patients with acute myeloid leukemia (AML) treated with azacitidine–venetoclax. Several issues should be addressed before the manuscript can be considered for publication.

Abstract

The Methods section of the abstract would benefit from greater methodological specificity. Please clearly state the study design and the statistical methods used.

The Results section should include available key quantitative outcomes to provide readers with a clearer understanding of the magnitude of the effects.

Methods

As this is a retrospective observational case series, please clarify whether consecutive patients were included and discuss the potential for selection bias.

The manuscript states that WT1 thresholds (<50 copies in peripheral blood and <250 copies in bone marrow) were used. However, it is unclear whether MRD negativity was strictly defined according to these thresholds and whether confirmatory measurements were required.

Please clarify how missing data were handled.

Results

With only 24 patients, subgroup analyses (early vs. late dose reduction) are underpowered. Several comparisons are interpreted despite non-significant p-values. Please avoid overinterpretation of numerical trends that lack statistical support.

Although Table 3 reports no statistically significant differences between groups, the small sample size limits the ability to detect baseline imbalances. Please discuss the potential for residual confounding.

Others

Minor typographical inconsistencies (e.g., “Kaplan–Meyer” instead of “Kaplan–Meier”) should be corrected.

Author Response

The manuscript addresses the role of measurable residual disease (MRD) monitoring using WT1 expression to guide venetoclax dose adjustment in unfit patients with acute myeloid leukemia (AML) treated with azacitidine–venetoclax. Several issues should be addressed before the manuscript can be considered for publication.

 

Comment 1. Abstract. The Methods section of the abstract would benefit from greater methodological specificity. Please clearly state the study design and the statistical methods used.

The Results section should include available key quantitative outcomes to provide readers with a clearer understanding of the magnitude of the effects.

Response to Comment 1. We thank the Reviewer for this comment, and we have rewritten the abstract as follows.

“Background/Objectives: Minimal residual disease (MRD) negativity is associated with improved outcomes in acute myeloid leukemia (AML) patients. In this retrospective observational real-life case series study, we investigated efficacy and safety of venetoclax dose adjustment in unfit AML patients, and the role of WT1 expression levels as a surrogate marker of MRD monitoring. Methods: A total of 24 consecutive unfit AML patients treated with azacytidine and venetoclax were enrolled in this study, and MRD monitoring was performed by flow cytometry as per international guidelines, and by WT1 expression levels assessed by RT-qPCR. Dose adjustment of venetoclax was decided based on MRD status and the onset of grade >2 neutropenia. Results: The overall response rate was 87.5%, and 16 patients achieved a response already at the first re-evaluation (66.7%). No statistically significant differences were observed between patients who received the standard dose and those with venetoclax dose adjustment in terms of overall survival (19.6 months vs 30.1 months, respectively; P = 0.9428) and progression-free survival (not reached vs 22.1 months, respectively; P = 0.3865), although a numerical trend toward lower relapse rates was observed in subjects with late (33.3%) or early and late reduction (37.5%) compared to those who had dose adjustment only at the first re-evaluation (75%) (P = 0.3014). Toxicity rate was 33.3% in patients who had early and late dose adjustments, lower than that observed with early adjustment (58.3%), and to that reported in the VIALE A study (84%). Conclusions: Reduced-dose venetoclax regimens (from 28 to 21 days per cycle) in unfit AML patients, without affecting response rates or survival, with comparable rates of neutropenia and infectious events, supporting flexible dosing strategies based on patient response and side effects. In addition, WT1 gene expression could serve as a reliable marker for MRD monitoring. However, larger prospective trials are needed for confirmation However, larger prospective trials are needed for confirmation of our preliminary, hypothesis-generating findings.”

 

Comment 2. As this is a retrospective observational case series, please clarify whether consecutive patients were included and discuss the potential for selection bias.

Response to Comment 2. We have included only consecutive patients, therefore there is no selection bias. We have clearly stated it in the Materials and Methods section.

 

Comment 3. The manuscript states that WT1 thresholds (<50 copies in peripheral blood and <250 copies in bone marrow) were used. However, it is unclear whether MRD negativity was strictly defined according to these thresholds and whether confirmatory measurements were required.

Response to Comment 3. We apologize for the lack of clarity, and we have changed the sentence as follows. We have also changed the title to “Personalized Venetoclax Dose Adjustment in Unfit Acute Myeloid Leukemia Patients: a real-life case series study”.

On lines 121-126, the following text was added “Venetoclax dosage was reduced in patients after MRD negativity was achieved or in case of severe grade III-IV neutropenia. MRD monitoring was carried out by flow cytometry immunophenotyping and by circulating WT1 expression levels by RT-qPCR assay after every cycle of therapy and at relapses. MRD negativity was defined according to the 2022 ELN guidelines [32].”

The following reference was also included.

[32] Ravandi F, Cloos J, Buccisano F, Dillon R, Döhner K, Freeman SD, Hourigan CS, Ossenkoppele GJ, Roboz GJ, Subklewe M, Thiede C, Arnhardt I, Valk PJM, Venditti A, Wei AH, Walter RB, Heuser M. Measurable residual disease monitoring in patients with acute myeloid leukemia treated with lower-intensity therapy: Roadmap from an ELN-DAVID expert panel. Am J Hematol. 2023 Dec;98(12):1847-1855.

 

Comment 4. Please clarify how missing data were handled.

Response to Comment 4. Missing data were handled using pairwise deletion. This information was added on line 173.

 

Comment 5. With only 24 patients, subgroup analyses (early vs. late dose reduction) are underpowered. Several comparisons are interpreted despite non-significant p-values. Please avoid overinterpretation of numerical trends that lack statistical support.

Response to Comment 5. We agree with the Reviewer, and we have avoided overinterpretations throughout the manuscript.

Moreover, in the Introduction section, we have rephrased as follows “For these reasons, in this retrospective observational real-life case series study, we aimed to: (i) provide additional evidence to the effective and safe use of reduced venetoclax dose from 28 to 21 days per cycle in unfit/frail AML patients not eligible to intensive chemotherapy; and (ii) investigate the potential role of circulating WT1 expression levels as a surrogate marker for MRD monitoring, when other disease-specific molecular alterations are present. These MRD-based venetoclax dose adjustments support a personalized therapeutic approach in unfit/frail patients in a real-life setting, to maximize clinical efficacy while minimizing treatment-related toxicities.”

In the Conclusion section, we have rephrased as follows “Our preliminary results add evidence for the effective use of reduced-dose venetoclax (from 28 to 21 days per cycle) in unfit/frail AML patients, without affecting response rates, survival, or incidence of side effects. In addition, WT1 gene expression could represent a candidate reliable marker for MRD monitoring, when other molecular alterations are not present. However, larger prospective trials are needed for confirmation.”

 

Comment 6. Although Table 3 reports no statistically significant differences between groups, the small sample size limits the ability to detect baseline imbalances. Please discuss the potential for residual confounding.

Response to Comment 6. We agree with the Reviewer on this point, and we have acknowledged this limitation on lines 209-2013, as the sentence has been rephrased as follows “No differences in clinical characteristics were observed between patients who reduced venetoclax dose at the first re-evaluation and those who never reduced the dose or reduced it later during the clinical course; however, the small number of patients per group does not allow definitive conclusions and adjustment for potential confounding factors (Table 3).”

 

Comment 7. Minor typographical inconsistencies (e.g., “Kaplan–Meyer” instead of “Kaplan–Meier”) should be corrected.

Response to Comment 7. We apologize for inconsistencies, and we have checked them throughout the manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

The study provides valuable data on a relevant clinical challenge, optimizing venetoclax dosing in AML patients using WT1 as a marker. The small cohort is a primary limitation that restricts the generalizability of the findings, and the statistical power of the comparative analyses.

Please soften the wording in the Conclusion and abstract to emphasize that these are preliminary, hypothesis-generating findings.

Please clarify if any patients had their dose reduced solely because their WT1 levels or if the neutropenia was the primary requirement for all dose changes in this cohort.

Author Response

The study provides valuable data on a relevant clinical challenge, optimizing venetoclax dosing in AML patients using WT1 as a marker. The small cohort is a primary limitation that restricts the generalizability of the findings, and the statistical power of the comparative analyses.

Comment 1. Please soften the wording in the Conclusion and abstract to emphasize that these are preliminary, hypothesis-generating findings.

Response to Comment 1. We agree with the Reviewer, and we have avoided overinterpretations throughout the manuscript.

Moreover, in the Introduction section, we have rephrased as follows “For these reasons, in this retrospective observational real-life case series study, we aimed to: (i) add evidence to the effective and safe use of reduced venetoclax dose from 28 to 21 days per cycle in unfit/frail AML patients not eligible to intensive chemotherapy; and (ii) to investigate the potential role of circulating WT1 expression levels as a surrogate marker for MRD monitoring, when other disease-specific molecular alterations are pre-sent. This MRD-based venetoclax dose adjustments support the use of personalized therapeutic approach in unfit/frail patients in a real-life setting, to maximize clinical efficacy while minimizing treatment-related toxicities.”

In the Conclusion section, we have rephrased as follows “Our preliminary results add evidence for the effective use of reduced-dose venetoclax (from 28 to 21 days per cycle) in unfit/frail AML patients, without affecting response rates, survival, or incidence of side effects. In addition, WT1 gene expression could represent a candidate reliable marker for MRD monitoring, when other molecular alterations are not present. However, larger prospective trials are needed for confirmation.”

 

Comment 2. Please clarify if any patients had their dose reduced solely because their WT1 levels or if the neutropenia was the primary requirement for all dose changes in this cohort.

Response to Comment 2. We apologize for our lack of clarity, and on lines 121-126, the following text was added “Venetoclax dosage was reduced in patients after MRD negativity was achieved or in case of severe grade III-IV neutropenia. MRD monitoring was carried out by flow cytometry immunophenotyping and by circulating WT1 expression levels by RT-qPCR assay after every cycle of therapy and at relapses. MRD negativity was defined according to 2022 ELN guidelines [32].”