Defining the Optimal Total Number of Chemotherapy Courses in Younger Patients With Acute Myeloid Leukemia: A Comparison of Three Versus Four Courses

Targeting Molecular Measurable Residual Disease and Low-Blast Relapse in AML With Venetoclax and Low-Dose Cytarabine: A Prospective Phase II Study (VALDAC)

PURPOSE

A prospective phase II study examined the safety and efficacy of venetoclax combined with low-dose cytarabine (LDAC) in AML at first measurable residual disease (MRD) or oligoblastic relapse.

METHODS

Patients with either MRD (≥1 log10 rise) or oligoblastic relapse (blasts 5%-15%) received venetoclax 600 mg once daily D1-28 plus LDAC once daily D1-10 in 28-day cycles. The primary objective was MRD response in the MRD relapse cohort or complete remission (CR/CRh/CRi) in the oligoblastic relapse cohort.

RESULTS

Forty-eight adults with either MRD (n = 26) or oligoblastic (n = 22) relapse were enrolled. Median age was 67 years (range, 18-80) and 94% had received previous intensive chemotherapy. Patients received a median of four cycles of therapy; 17% completed ≥12 cycles. Patients with oligoblastic relapse had more grade ≥3 anemia (32% v 4%; P = .02) and infections (36% v 8%; P = .03), whereas grade 4 neutropenia (32 v 23%) or thrombocytopenia (27 v 15%) were comparable with the MRD relapse cohort. Markers of molecular MRD relapse included mutant NPM1 (77%), CBFB::MYH11 (4%), RUNX1::RUNX1T1 (4%), or KMT2A::MLLT3 (4%). Three patients with a log10 rise in IDH1/2 (12%) were included. By cycle 2 in the MRD relapse cohort, a log10 reduction in MRD was observed in 69%; 46% achieved MRD negative remission. In the oligoblastic relapse cohort, 73% achieved CR/CRh/CRi. Overall, 21 (44%) underwent hematopoietic cell transplantation. Median overall survival (OS) was not reached in either cohort. Estimated 2-year OS rate was 67% (95% CI, 50 to 89) in the MRD and 53% (95% CI, 34 to 84) in the oligoblastic relapse cohorts.

CONCLUSION

For AML in first remission and either MRD or oligoblastic relapse, venetoclax plus LDAC is well tolerated and highly effective.

Literature review and expert opinion on the treatment of high-risk acute myeloid leukemia in patients who are eligible for intensive chemotherapy

In patients with Acute Myeloid Leukemia (AML), the assessment of disease risk plays a central role in the era of personalized medicine. Indeed, integrating baseline clinical and biological features on a case-by-case basis is not only essential to select which treatment would likely result in a higher probability of achieving complete remission, but also to dynamically customize any subsequent therapeutic intervention. For young high-risk patients with low comorbidities burden and in good general conditions (also called "fit" patients), intensive chemotherapy followed by allogeneic stem cell transplantation still represents the backbone of any therapeutic program. However, with the approval of novel promising agents in both the induction/consolidation and the maintenance setting, the algorithms for the management of AML patients considered eligible for intensive chemotherapy are in constant evolution. In this view, we selected burning issues regarding the identification and management of high-risk AML, aiming to provide practical advice to facilitate their daily clinical management in patients considered eligible for intensive chemotherapy.

Toxicity and outcome of adults with acute myeloid leukemia receiving consolidation with high-dose cytarabine

INTRODUCTION

High-dose cytarabine is considered standard of care as consolidation chemotherapy in adults with acute myeloid leukemia (AML) who are not eligible for allogeneic hematopoietic cell transplantation, but may be associated with significant toxicity. We evaluated the toxicity associated with high-dose cytarabine given as consolidation in AML patients treated at a Brazilian public hospital.

METHODS

We retrospectively reviewed the charts of all patients with AML treated between 2008 and 2020 who obtained complete remission (CR) after one cycle of induction chemotherapy and received consolidation with at least one cycle of high-dose cytarabine (defined as 3 g/m2 every 12 h days 1, 3 and 5).

RESULTS

Among 61 patients who received induction remission, 32 obtained CR and 28 received at least one cycle of high-dose cytarabine, for a total of 67 cycles (median 2 cycles per patient, range 1 - 4). In 45 cycles (67.2%) the patient was discharged after the end of chemotherapy, with a median of 6 days at home (range 3 - 8). Readmission occurred in 31 of the 45 cycles (68.9%). The most frequent toxicities were febrile neutropenia (56.7%), nausea and vomiting (23.9%), oral mucositis (14.9%) and diarrhea (11.9%). Bacteremia was documented in 13 cycles (34.2%). There were three cases of typhlitis and two of invasive fungal disease (aspergillosis and candidemia). Four patients died (14.3%), with two deaths considered treatment-related (candidemia and typhlitis).

CONCLUSION

In the setting of a Brazilian public hospital, high-dose cytarabine as consolidation therapy is feasible, with manageable toxicity profile.

A Question of Frame: The Role of the Bone Marrow Stromal Niche in Myeloid Malignancies

Until a few years ago, the onset of acute myeloid leukemia (AML) was entirely ascribed to genetic lesions in hematopoietic stem cells. These mutations generate leukemic stem cells, which are known to be the main ones responsible for chemoresistance and relapse. However, in the last years, increasing evidence demonstrated that dynamic interplay between leukemic cells and bone marrow (BM) niche is of paramount relevance in the pathogenesis of myeloid malignancies, including AML. Specifically, BM stromal niche components, such as mesenchymal stromal cells (MSCs) and their osteoblastic cell derivatives, play a key role not only in supporting normal hematopoiesis but also in the manifestation and progression of myeloid malignancies. Here, we reviewed recent clinical and experimental findings about how genetic and functional alterations in MSCs and osteolineage progeny can contribute to leukemogenesis and how leukemic cells in turn generate a corrupted niche able to support myeloid neoplasms. Moreover, we discussed how the newest single-cell technologies may help dissect the interactions between BM stromal cells and malignant hematopoiesis. The deep comprehension of the tangled relationship between stroma and AML blasts and their modulation during disease progression may have a valuable impact on the development of new microenvironment-directed therapeutic strategies, potentially useful for a wide cohort of patients.

Acute Myeloid Leukemia Stem Cells in Minimal/Measurable Residual Disease Detection

Acute myeloid leukemia (AML) is a hematological malignancy characterized by an abundance of incompletely matured or immature clonally derived hematopoietic precursors called leukemic blasts. Rare leukemia stem cells (LSCs) that can self-renew as well as give rise to leukemic progenitors comprising the bulk of leukemic blasts are considered the cellular reservoir of disease initiation and maintenance. LSCs are widely thought to be relatively resistant as well as adaptive to chemotherapy and can cause disease relapse. Therefore, it is imperative to understand the molecular bases of LSC forms and functions during different stages of disease progression, so we can more accurately identify these cells and design therapies to target them. Irrespective of the morphological, cytogenetic, and cellular heterogeneity of AML, the uniform, singularly important and independently significant prognosticator of disease response to therapy and patient outcome is measurable or minimal residual disease (MRD) detection, defined by residual disease detection below the morphology-based 5% blast threshold. The importance of LSC identification and frequency estimation during MRD detection, in order to make MRD more effective in predicting disease relapse and modifying therapeutic regimen is becoming increasingly apparent. This review focuses on summarizing functional and cellular composition-based LSC identification and linking those studies to current techniques of MRD detection to suggest LSC-inclusive MRD detection as well as outline outstanding questions that need to be addressed to improve the future of AML clinical management and treatment outcomes.

Characteristics and outcome of primary resistant disease in paediatric acute myeloid leukaemia

A significant proportion of events in paediatric acute myeloid leukaemia (AML) are caused by resistant disease (RD). We investigated clinical and biological characteristics in 66 patients with RD from 1013 children with AML registered and treated according to the NOPHO-AML 93, NOPHO-AML 2004, DB AML-01 and NOPHO-DBH AML 2012 protocols. Risk factors for RD were age10 years or older and a white-blood-cell count (WBC) of 100 × 10⁹ /L or more at diagnosis. The five-year overall survival (OS) was 38% (95% confidence interval [CI]: 28%-52%). Of the 63 children that received salvage therapy with chemotherapy, 59% (N = 37) achieved complete remission (CR) with OS 57% (95% CI: 42%-75%) compared to 12% (95% CI: 4%-35%) for children that did not achieve CR. Giving more than two salvage chemotherapy courses did not increase CR rates. OS for all 43 patients receiving allogeneic haematopoietic stem cell transplantation (HSCT) was 49% (95% CI: 36%-66%). Those achieving CR and proceeding to HSCT had an OS of 56% (95% CI: 41%-77%, N = 30). This study showed that almost 40% of children with primary resistant AML can be cured with salvage therapy followed by HSCT. Children that did not achieve CR after two salvage courses with chemotherapy did not benefit from additional chemotherapy.

Clinical Impact of Measurable Residual Disease in Acute Myeloid Leukemia

Simple Summary

Advances in immunophenotyping and molecular techniques have allowed for the development of more sensitive diagnostic tests in acute leukemia. These techniques can identify low levels of leukemic cells (quantified as 10⁻⁴ to 10⁻⁶ ratio to white blood cells) in patient samples. The presence of such low levels of leukemic cells, termed “measurable/minimal residual disease” (MRD), has been shown to be a marker of disease burden and patient outcomes. In acute lymphoblastic leukemia, new agents are highly effective at eliminating MRD for patients whose leukemia progressed despite first line therapies. By comparison, the role of MRD in acute myeloid leukemia is less clear. This commentary reviews select data and remaining questions about the clinical application of MRD to the treatment of patients with acute myeloid leukemia.

Abstract

Measurable residual disease (MRD) has emerged as a primary marker of risk severity and prognosis in acute myeloid leukemia (AML). There is, however, ongoing debate about MRD-based surveillance and treatment. A literature review was performed using the PubMed database with the keywords MRD or residual disease in recently published journals. Identified articles describe the prognostic value of pre-transplant MRD and suggest optimal timing and techniques to quantify MRD. Several studies address the implications of MRD on treatment selection and hematopoietic stem cell transplant, including patient candidacy, conditioning regimen, and transplant type. More prospective, randomized studies are needed to guide the application of MRD in the treatment of AML, particularly in transplant.

Oncology stewardship in acute myeloid leukemia

In recent years, an explosion of novel agents has shifted the treatment paradigm for patients with acute myeloid leukemia. The optimal place in therapy for many of these novel agents remains unknown due to limited guidance from national guidelines and the way these agents were studied prior to entering the market. A critical evaluation of the literature and incorporation of oncology stewardship principles can be helpful in determining an optimal place for these agents while being mindful of the overall cost that is associated with therapies. The purpose of this review is to critically evaluate the efficacy and safety data for five controversial agents and provide examples of the use of stewardship practices in determining their place in the treatment of acute myeloid leukemia.

Venetoclax combined with induction chemotherapy in patients with newly diagnosed acute myeloid leukaemia: a post-hoc, propensity score-matched, cohort study

BACKGROUND

Venetoclax combined with intensive chemotherapy has been shown to be safe with promising activity in fit patients with newly diagnosed acute myeloid leukaemia. The aim of this study was to compare the activity of venetoclax plus intensive chemotherapy with intensive chemotherapy alone.

METHODS

This was a post-hoc propensity score matched analysis of prospective clinical trials (NCT03214562, NCT02115295, and NCT01289457) in patients at The University of Texas MD Anderson Cancer Center, Texas, USA between March 29, 2010, and June 15, 2021. Eligible patients were aged 18 years and older, and had newly diagnosed acute myeloid leukaemia or high-risk myelodysplastic syndrome, and were treated within trials incorporating purine analogues with an anthracycline and cytarabine either with venetoclax plus intensive chemotherapy or with intensive chemotherapy alone. Patients in the venetoclax plus intensive chemotherapy cohort were matched with patients in the intensive chemotherapy cohort. Morphological response and measurable residual disease (MRD) was assessed using bone marrow aspiration and biopsy and eight-colour multiparameter flow cytometry. The primary objectives were rate of MRD negative composite complete response and cumulative incidence of transition to allogeneic haematopoietic stem-cell transplantation (HSCT). All patients who had response within two treatment cycles (induction and re-induction) were included in the analyses. Secondary objectives included assessment of event-free and overall survival.

FINDINGS

The propensity matched cohort included 279 patients (median age 49 years [IQR 39-57]; 131 [47%] were men and 148 [53%] were women); 85 in the venetoclax plus intensive chemotherapy cohort and 194 in the intensive chemotherapy cohort. After a median follow up of 30 months (95% CI 26-36), 64 (86%) of 74 patients in the venetoclax plus intensive chemotherapy cohort had an MRD-negative composite complete response rate compared with 86 [61%] of 140 patients in the intensive chemotherapy cohort (odd ratio 3·2 [95% CI 1·5-6·7]; p=0·0028). The overall cumulative incidence of allogeneic HSCT in responding patients was higher with venetoclax plus intensive chemotherapy than intensive chemotherapy (79% [95% CI 67-88] vs 57% [49-65]; hazard ratio [HR] 1·52 [95% CI 1·11-2·08]; p=0·012). Venetoclax plus intensive chemotherapy improved event-free survival (median not reached [NR; 95% CI NR-NR] vs 14·3 months [10·7-33·5]; HR 0·57 [95% CI 0·34-0·95]; p=0·030), but overall survival did not significantly differ between the two cohorts (median NR [95% CI 24-NR] vs 32 months [19-NR]; HR 0·63 [95% CI 0·35-1·1], p=0·13).

INTERPRETATIONS

Venetoclax combined with intensive induction chemotherapy induced deep MRD-negative remissions, allowing transition to allogeneic HSCT in first remission, and improvement in event-free survival. These results highlight the incremental benefit of venetoclax added to intensive induction chemotherapy across European LeukemiaNet risk groups, and serve as a benchmark to inform enrolment on future confirmatory prospective clinical trials.

FUNDING

None.

Neutropenia in the First Cycle of Consolidation Chemotherapy with High-Dose Cytarabine Is Not Associated with the Incidence of Relapse in Adult Acute Myeloid Leukemia Patients in First Complete Remission

BACKGROUND

It has been reported that prolonged neutropenia during post-remission chemotherapy is associated with a reduced risk of disease relapse in pediatric acute myeloid leukemia (AML) patients.

METHODS

We retrospectively reviewed the charts of adult AML patients in first complete remission (CR1) who underwent consolidation chemotherapy with high-dose cytarabine. Those receiving allogeneic hematopoietic cell transplantation in CR1 were excluded. We calculated the D-index, which is an area-based neutropenia index. The patients were divided into 2 groups using the median value of the D-index during the first cycle of consolidation chemotherapy (C#1).

RESULTS

Fifty-six patients were included. The 2-year cumulative incidence of relapse was 54.8% (95% confidence interval (CI): 37.5-73.8) in patients with a D-index < 5,118 and 62.0% (95%CI: 42.7-81.4) in those with a D-index ≥ 5,118 (P = 0.56). In a multivariate analysis, intermediate / adverse cytogenetic risk (HR 2.76), performance status ≥ 2 (HR 5.55) and 2 cycles of induction chemotherapy required to achieve CR1 (HR 4.29) were identified as significant factors associated with relapse. The D-index at C#1 did not have a significant impact.

CONCLUSIONS

In contrast to pediatric patients, the severity of neutropenia is not associated with a risk of disease relapse in adult AML patients.

Azacitidine to Consolidate and Deepen the Therapeutic Response Achieved by Intensive Induction Treatment in a Young Patient Affected by NPM1mut-AML Who Has Become Ineligible for High-Dose Consolidation

Acute myeloid leukemia (AML) is the most common leukemia in adults. In spite of the most recent discoveries about the molecular landscape of this disease, the treatment of elderly and unfit young patients continues to be a great challenge. The hypomethylating agents (HMA) still represent an effective therapeutic option for these categories, especially for the low-risk subgroups. We report the case of a young patient with NPM1mut-AML who underwent a first cycle of intensive induction treatment, achieving a complete remission, but suffered from a serious life-threatening neurologic toxicity. Due to the ineligibility to further lines of intensive chemotherapy, we decided to consolidate the response with azacitidine, administered according to the regular schedule. The minimal residual disease (MRD), monitored through the NPM1 mutation at diagnosis, progressively decreased and became undetectable after 36 cycles of hypomethylating therapy. After 1 year from discontinuation of azacitidine, MRD remains undetectable. Therefore, HMA might still represent a feasible and effective option for patients with low-risk AML, especially when the standard chemotherapy is not indicated, or as maintenance therapy in nontransplantable patients.

Cytarabine dose reduction in patients with low-risk acute myeloid leukemia: A report from the Children's Oncology Group

BACKGROUND

The optimal number of chemotherapy courses for low-risk (LR) pediatric acute myeloid leukemia (AML) is not known.

OBJECTIVE

To compare outcomes for four (21.6 g/m² cytarabine) versus five (45.6 g/m² cytarabine) chemotherapy courses for LR-AML using data from Children's Oncology Group (COG) AAML0531 and AAML1031.

METHODS

We compared relapse risk (RR), disease-free survival (DFS), and overall survival (OS), and the differential impact in LR subgroups for patients receiving four versus five chemotherapy courses. Cox (OS and DFS) and risk (RR) regressions were used to estimate hazard ratios (HR) to compare outcomes.

RESULTS

A total of 923 LR-AML patients were included; 21% received five courses. Overall, LR-AML patients who received four courses had higher RR (40.9% vs. 31.4%; HR = 1.40, 95% confidence interval [CI]: 1.06-1.85), and worse DFS (56.0% vs. 67.0%; HR = 1.45, 95% CI: 1.10-1.91). There was a similar decrement in OS though it was not statistically significant (77.0% vs. 83.5%; HR = 1.45, 95% CI: 0.97-2.17). Stratified analyses revealed the detrimental effects of cytarabine dose de-escalation to be most pronounced in the LR-AML subgroup with uninformative cytogenetic/molecular features who were minimal residual disease (MRD) negative after the first induction course (EOI1). The absolute decrease in DFS with four courses for patients with favorable cytogenetic/molecular features and positive MRD was similar to that observed for patients with uninformative cytogenetic/molecular features and negative MRD at EOI1, though not statistically significant.

CONCLUSIONS

Our results support de-escalation of cytarabine exposure through the elimination of a fifth chemotherapy course only for LR-AML patients who have both favorable cytogenetic/molecular features and negative MRD after the first induction cycle.

2021 Update on MRD in acute myeloid leukemia: a consensus document from the European LeukemiaNet MRD Working Party

Measurable residual disease (MRD) is an important biomarker in acute myeloid leukemia (AML) that is used for prognostic, predictive, monitoring, and efficacy-response assessments. The European LeukemiaNet (ELN) MRD Working Party evaluated standardization and harmonization of MRD in an ongoing manner and has updated the 2018 ELN MRD recommendations based on significant developments in the field. New and revised recommendations were established during in-person and online meetings, and a 2-stage Delphi poll was conducted to optimize consensus. All recommendations are graded by levels of evidence and agreement. Major changes include technical specifications for next-generation sequencing-based MRD testing and integrative assessments of MRD irrespective of technology. Other topics include use of MRD as a prognostic and surrogate end point for drug testing; selection of the technique, material, and appropriate time points for MRD assessment; and clinical implications of MRD assessment. In addition to technical recommendations for flow- and molecular-MRD analysis, we provide MRD thresholds and define MRD response, and detail how MRD results should be reported and combined if several techniques are used. MRD assessment in AML is complex and clinically relevant, and standardized approaches to application, interpretation, technical conduct, and reporting are of critical importance.

Is the current consolidation regimen for AML evidence-based?

Current standard of care for consolidation therapy for AML varies based on age and induction regimen, among other factors. Many trials have sought to determine the optimal dose, number of cycles, and schedule for consolidation with cytarabine. For AML patients under age 60, mid-dose cytarabine is as effective as high-dose cytarabine, results after 3 or 4 cycles of cytarabine in consolidation are comparable but are both superior to only one cycle, and giving cytarabine every 12 h on days 1, 2, and 3 appears to have the same benefit but less toxicity than cytarabine given on days 1, 3, and 5. For those over age 60, the best dose of cytarabine is unknown, but post-remission therapy appears to improve survival for some patients who achieve remission after standard induction, depending on induction regimen used and MRD status at time of remission.

Post-Induction Treatment for Acute Myeloid Leukemia: Something Change?

PURPOSE OF REVIEW

Until recently, improvement in terms of survival for patients with acute myeloid leukemia (AML) was achieved mostly in younger patients with dose intensification of conventional chemotherapy and a broadening use of allogeneic hematopoietic cell transplantation (allo-HCT) whereas the results remained dismal and very stable in patients older than 60 years. The current review highlights the recent developments in standard intensive post-remission chemotherapy, evidence for the use of recently approved agents, and discusses the relevance of measurable residual disease (MRD) measurement in treatment adaptation.

RECENT FINDINGS

Current approvals of midostaurin, venetoclax, gemtuzumab ozogamicin, VYXEOS, ivosidenib, enasidenib, glasdegib, and CC-486 have changed the structure, aim, and schedule of consolidation therapy, and new, well-tolerated agents are being evaluated as maintenance therapies. Furthermore, MRD assessment has been implemented to guide the duration and type of consolidation and maintenance therapy as well as indicate the optimal timing of allo-HCT. Novel therapies have changed the structure and perspective of post-remission therapy in AML for both young and elderly patients. In addition, MRD assessment could guide the type, duration, and intensity of consolidation and maintenance therapy.