Clinical Edge Journal Scan Commentary: AML July 2021

Measurable residual disease (MRD) in acute myeloid leukemia (AML) is both predictive and prognostic. However, the best time and method to define its prognostic role remains unclear. This month, 2 papers evaluate the role of MRD testing at different time points during therapy.

The first paper by Tsai et al studied MRD by next-generation sequencing (NGS) after induction and consolidation. The second paper by Kim et al evaluated the role of NGS MRD before and after allogeneic hematopoietic cell transplantation (allo-HCT).

The study by Tsai et al was a retrospective study that analyzed 1005 bone marrow samples serially collected at diagnosis, the first CR after induction chemotherapy (MRD^1st), and after the first consolidation (MRD^2nd) chemotherapy from 335 patients with de novo AML. Patients with antecedent cytopenia, hematologic diseases, and therapy-related AML (t-AML) were excluded. Patients who achieved complete remission with incomplete hematologic recovery (CRi) or had DNMT3A, TET2, and ASXL1 (DTA) only mutations were not included in the analysis. Multiple previous studies have demonstrated that persistence of DTA only mutations have no prognostic impact. Patients with positive MRD^1st (MRD^1st-)but negative MRD^2nd (MRD^2nd-)had good prognosis similar to those with negative MRD at both time points (cumulative incidence of relapse (CIR), P = .140; relapse-free survival (RFS), P = .231; overall survival (OS), P = .188). The median OS for patients with MRD^1st-MRD2^nd- (n = 147), and MRD^1st+MRD^2nd- (n = 60) was not reached compared to 3.1 years for patients with MRD^1st+MRD^2nd+ (n = 75). Only 9 patients progressed from MRD^1st- to MRD^2nd+ and their median survival was 3.6 years.

In the study by Kim et al utilizing NGS pre- and postHCT, the detection of MRD using NGS had a prognostic value before and 1 month after allo-HCT. This study included 146 patients with AML who underwent allo-HCT in complete remission between 2013 and 2018. The OS was 82%, 64%, and 44% for patients who were MRD negative both pre and post HCT, MRD+ then MRD- after alloHCT and MRD+ both pre- and postHCT respectively. In this study, myeloablative conditioning (MAC) pre allo-HCT did not overcome the negative prognostic value of MRD+ disease prior to allo-HCT. This is in contradiction to the BMT CTN0901 where MAC did overcome the negative prognostic impact of MRD+ disease prior to alloHCT. The authors suggest that this difference could be due to the limited number of genes assessed in the BMT CTN0901 study. Both of those studies demonstrate that achieving NGS MRD negativity either with chemotherapy consolidation or alloHCT leads to better outcome and can be used as a meaningful endpoint in AML studies.

Another completely different direction to improve patient outcomes is the evaluation of the gut microbiota. Several studies have demonstrated the negative impact of disturbed gut microbiota on several outcomes in patients with AML receiving intensive chemotherapy. A study by Malard et al demonstrated that autologous fecal microbiota transfer (AFMT) was safe and effective for gut microbiota restoration in patients with AML receiving intensive chemotherapy and antibiotics. After AFMT treatment, α-diversity indices returned to their initial median levels (Shannon index, P = .70; Inverse Simpson index, P = .90) and the b-diversity index showed the restoration of microbial communities, particularly for Lachnospiraceae and Ruminococcaceae families. Gut microbiota composition was preserved even after consolidation chemotherapy with high-dose cytarabine. No serious adverse events were reported, and only 3 patients experienced transient gastrointestinal symptoms. This approach may be considered in the future to improve the outcome of patients or allogeneic stool transfer is another option currently being studied. Clearly gut microbiota have an effect on outcome, and future studies will demonstrate the best and safest way to reconstitute gut microbiota in patients with hematological malignancies.

Measurable residual disease (MRD) in acute myeloid leukemia (AML) is both predictive and prognostic. However, the best time and method to define its prognostic role remains unclear. This month, 2 papers evaluate the role of MRD testing at different time points during therapy.

The first paper by Tsai et al studied MRD by next-generation sequencing (NGS) after induction and consolidation. The second paper by Kim et al evaluated the role of NGS MRD before and after allogeneic hematopoietic cell transplantation (allo-HCT).

The study by Tsai et al was a retrospective study that analyzed 1005 bone marrow samples serially collected at diagnosis, the first CR after induction chemotherapy (MRD^1st), and after the first consolidation (MRD^2nd) chemotherapy from 335 patients with de novo AML. Patients with antecedent cytopenia, hematologic diseases, and therapy-related AML (t-AML) were excluded. Patients who achieved complete remission with incomplete hematologic recovery (CRi) or had DNMT3A, TET2, and ASXL1 (DTA) only mutations were not included in the analysis. Multiple previous studies have demonstrated that persistence of DTA only mutations have no prognostic impact. Patients with positive MRD^1st (MRD^1st-)but negative MRD^2nd (MRD^2nd-)had good prognosis similar to those with negative MRD at both time points (cumulative incidence of relapse (CIR), P = .140; relapse-free survival (RFS), P = .231; overall survival (OS), P = .188). The median OS for patients with MRD^1st-MRD2^nd- (n = 147), and MRD^1st+MRD^2nd- (n = 60) was not reached compared to 3.1 years for patients with MRD^1st+MRD^2nd+ (n = 75). Only 9 patients progressed from MRD^1st- to MRD^2nd+ and their median survival was 3.6 years.

In the study by Kim et al utilizing NGS pre- and postHCT, the detection of MRD using NGS had a prognostic value before and 1 month after allo-HCT. This study included 146 patients with AML who underwent allo-HCT in complete remission between 2013 and 2018. The OS was 82%, 64%, and 44% for patients who were MRD negative both pre and post HCT, MRD+ then MRD- after alloHCT and MRD+ both pre- and postHCT respectively. In this study, myeloablative conditioning (MAC) pre allo-HCT did not overcome the negative prognostic value of MRD+ disease prior to allo-HCT. This is in contradiction to the BMT CTN0901 where MAC did overcome the negative prognostic impact of MRD+ disease prior to alloHCT. The authors suggest that this difference could be due to the limited number of genes assessed in the BMT CTN0901 study. Both of those studies demonstrate that achieving NGS MRD negativity either with chemotherapy consolidation or alloHCT leads to better outcome and can be used as a meaningful endpoint in AML studies.

Another completely different direction to improve patient outcomes is the evaluation of the gut microbiota. Several studies have demonstrated the negative impact of disturbed gut microbiota on several outcomes in patients with AML receiving intensive chemotherapy. A study by Malard et al demonstrated that autologous fecal microbiota transfer (AFMT) was safe and effective for gut microbiota restoration in patients with AML receiving intensive chemotherapy and antibiotics. After AFMT treatment, α-diversity indices returned to their initial median levels (Shannon index, P = .70; Inverse Simpson index, P = .90) and the b-diversity index showed the restoration of microbial communities, particularly for Lachnospiraceae and Ruminococcaceae families. Gut microbiota composition was preserved even after consolidation chemotherapy with high-dose cytarabine. No serious adverse events were reported, and only 3 patients experienced transient gastrointestinal symptoms. This approach may be considered in the future to improve the outcome of patients or allogeneic stool transfer is another option currently being studied. Clearly gut microbiota have an effect on outcome, and future studies will demonstrate the best and safest way to reconstitute gut microbiota in patients with hematological malignancies.

Measurable residual disease (MRD) in acute myeloid leukemia (AML) is both predictive and prognostic. However, the best time and method to define its prognostic role remains unclear. This month, 2 papers evaluate the role of MRD testing at different time points during therapy.

The first paper by Tsai et al studied MRD by next-generation sequencing (NGS) after induction and consolidation. The second paper by Kim et al evaluated the role of NGS MRD before and after allogeneic hematopoietic cell transplantation (allo-HCT).

The study by Tsai et al was a retrospective study that analyzed 1005 bone marrow samples serially collected at diagnosis, the first CR after induction chemotherapy (MRD^1st), and after the first consolidation (MRD^2nd) chemotherapy from 335 patients with de novo AML. Patients with antecedent cytopenia, hematologic diseases, and therapy-related AML (t-AML) were excluded. Patients who achieved complete remission with incomplete hematologic recovery (CRi) or had DNMT3A, TET2, and ASXL1 (DTA) only mutations were not included in the analysis. Multiple previous studies have demonstrated that persistence of DTA only mutations have no prognostic impact. Patients with positive MRD^1st (MRD^1st-)but negative MRD^2nd (MRD^2nd-)had good prognosis similar to those with negative MRD at both time points (cumulative incidence of relapse (CIR), P = .140; relapse-free survival (RFS), P = .231; overall survival (OS), P = .188). The median OS for patients with MRD^1st-MRD2^nd- (n = 147), and MRD^1st+MRD^2nd- (n = 60) was not reached compared to 3.1 years for patients with MRD^1st+MRD^2nd+ (n = 75). Only 9 patients progressed from MRD^1st- to MRD^2nd+ and their median survival was 3.6 years.

In the study by Kim et al utilizing NGS pre- and postHCT, the detection of MRD using NGS had a prognostic value before and 1 month after allo-HCT. This study included 146 patients with AML who underwent allo-HCT in complete remission between 2013 and 2018. The OS was 82%, 64%, and 44% for patients who were MRD negative both pre and post HCT, MRD+ then MRD- after alloHCT and MRD+ both pre- and postHCT respectively. In this study, myeloablative conditioning (MAC) pre allo-HCT did not overcome the negative prognostic value of MRD+ disease prior to allo-HCT. This is in contradiction to the BMT CTN0901 where MAC did overcome the negative prognostic impact of MRD+ disease prior to alloHCT. The authors suggest that this difference could be due to the limited number of genes assessed in the BMT CTN0901 study. Both of those studies demonstrate that achieving NGS MRD negativity either with chemotherapy consolidation or alloHCT leads to better outcome and can be used as a meaningful endpoint in AML studies.

Another completely different direction to improve patient outcomes is the evaluation of the gut microbiota. Several studies have demonstrated the negative impact of disturbed gut microbiota on several outcomes in patients with AML receiving intensive chemotherapy. A study by Malard et al demonstrated that autologous fecal microbiota transfer (AFMT) was safe and effective for gut microbiota restoration in patients with AML receiving intensive chemotherapy and antibiotics. After AFMT treatment, α-diversity indices returned to their initial median levels (Shannon index, P = .70; Inverse Simpson index, P = .90) and the b-diversity index showed the restoration of microbial communities, particularly for Lachnospiraceae and Ruminococcaceae families. Gut microbiota composition was preserved even after consolidation chemotherapy with high-dose cytarabine. No serious adverse events were reported, and only 3 patients experienced transient gastrointestinal symptoms. This approach may be considered in the future to improve the outcome of patients or allogeneic stool transfer is another option currently being studied. Clearly gut microbiota have an effect on outcome, and future studies will demonstrate the best and safest way to reconstitute gut microbiota in patients with hematological malignancies.