Molecular MRD is strongly prognostic in patients with NPM1-mutated AML receiving venetoclax-based nonintensive therapy

Recent advances in AML with mutated NPM1

Nucleophosmin 1 (NPM1) mutation is one of the most prevalent genetic mutations in adult acute myeloid leukemia (AML) and is particularly predominant in AML with a normal karyotype. NPM1 is a chaperone protein that plays various roles in several cellular processes. Wild-type NPM1 is normally localized to the nucleus, whereas mutant NPM1 proteins exhibit altered cytoplasmic localization. Clinically, AML with mutated NPM1 without FLT3-ITD is associated with a higher complete remission rate and improved overall survival. AML with mutated NPM1 is categorized as a distinct genetic entity in the World Health Organization classification of hematopoietic malignancies due to its unique clinical and biological features. However, the precise roles of NPM1 in normal hematopoiesis and in AML development remain unclear. Recent studies have revealed various clinical applications of NPM1 mutations in AML treatment, particularly in measurable residual disease analyses that target mutant NPM1 transcripts and in potential therapeutic applications of menin inhibitors and XPO-1 inhibitors for AML with mutated NPM1. Thus, NPM1 mutation is highly significant in AML classification, prognosis, response assessment, and molecular targeted therapies. Here, we review recent progress in clinical and biological aspects of AML with mutated NPM1 including molecular targeted therapy.

Measurable residual disease (MRD)-testing in haematological cancers: A giant leap forward or sideways?

Measurable residual disease (MRD)-testing is used in many haematological cancers to estimate relapse risk and to direct therapy. Sometimes MRD-test results are used for regulatory approval. However, some people including regulators wrongfully believe results of MRD-testing are highly accurate and of proven efficacy in directing therapy. We review MRD-testing technologies and evaluate the accuracy of MRD-testing for predicting relapse and the strength of evidence supporting efficacy of MRD-guided therapy. We show that at the individual level MRD-test results are often an inaccurate relapse predictor. Also, no convincing data indicate that increasing therapy-intensity based on a positive MRD-test reduces relapse risk or improves survival. We caution against adjusting therapy-intensity based solely on results of MRD-testing.

Successful rechallenge with azacytidine and venetoclax after sustained treatment-free remission in a relapsed acute myeloid leukemia patient: a case report

Combined therapy with venetoclax and hypomethylating agents has significantly improved the outcome of unfit patients ineligible for intensive chemotherapy. A recently published exploratory analysis of the VIALE-A trial reported that up to 51% of patients achieving remission survived more than 2 years. These data along with those from reallife settings, lead to questioning how long it is appropriate to continue treatment in long-term survivors. Accordingly, recent retrospective studies suggested the feasibility of suspending therapy in selected patients while maintaining prolonged responses. Also, these studies showed that retreatment may induce a second remission in almost a third of patients. We report the case of a patient who received salvage therapy with venetoclax and azacytidine, that was discontinued few cycles after blasts clearance because of severe hematological toxicity. Despite suspension, he maintained a sustained response lasting almost one year and was successfully retreated with the same combination when a second relapse occurred.

Combination therapy with novel agents for acute myeloid leukaemia: Insights into treatment of a heterogenous disease

The treatment landscape of acute myeloid leukaemia (AML) is evolving rapidly. Venetoclax in combination with intensive chemotherapy or doublets or triplets with targeted or immune therapies is the focus of numerous ongoing trials. The development of mutation-targeted therapies has greatly enhanced the treatment armamentarium, with FLT3 inhibitors and isocitrate dehydrogenase inhibitors improving outcomes in frontline and relapsed/refractory (RR) AML, and menin inhibitors showing efficacy in RR NPM1mut and KMT2A-rearranged AML. With so many new drugs approved, the number of potential combinatorial approaches to leverage the maximal benefit of these agents has increased dramatically, while at the same time introducing clinical challenges, such as key preclinical and clinical data supporting the development of combinatorial therapy, how to optimally combine or sequence these novel agents, how to optimise dose and duration to maintain safety while enhancing efficacy, the optimal duration of therapy and the role of measurable residual disease in decision-making in both intensive and low-intensity therapy settings. In this review, we will outline the evidence leading to the approval of key agents in AML, their on-label current approvals and how they may be optimally combined in a safe and deliverable fashion to further improve outcomes in AML.

Genetic variations in DNA excision repair pathway contribute to the chemosensitivity and prognosis of acute myeloid leukemia

Acute myeloid leukemia (AML) is a hematologic malignancy with a high recurrence rate and poor long-term prognosis. DNA excision repair systems, such as base excision repair (BER) and nucleotide excision repair (NER), play a major role in maintaining genomic stability and integrity. Further intensive investigations are necessary to uncover additional AML prognosis loci. In this study, we analyzed 16 candidate SNPs within NER and BER pathways in AML patients. Our results showed the GT/GG genotype of the XPC rs2228001 polymorphism was significantly associated with WBC count in dominant models (OR = 0.41, 95 % CI = 0.18-0.96, p = 0.039). Additionally, the rs25487 and rs3213245 SNPs in the XRCC1 gene, in both co-dominant and dominant models, were significantly associated with PLT count in AML (p < 0.05). The GG genotype of rs1130409 in APEX1 was more prone to adverse cytogenetics in both the codominant and recessive models (p < 0.05). Furthermore, the GA genotypes of ERCC8 rs158572 in codominant model was significantly correlated with refractory group (p < 0.05). ERCC8 rs158572 and XRCC1 rs3213245 in both codominant and dominant models were significantly correlated with the MRD positivity (p < 0.05). Kaplan-Meier analysis revealed an link between overall survival (OS) and the co-dominant, dominant, and recessive models of rs2228001 in XPC. Additionally, patients with the GG and GT/GG genotype in the co-dominant, dominant model and recessive model in XPC rs2228001 exhibited significantly longer survival (p < 0.05). Multivariate Cox analyses indicated that rs2228001 in both co-dominant and dominant models were independent favorable factors impacting patient OS (OR < 1). Our findings suggest that genetic polymorphisms in DNA excision repair pathway genetic polymorphisms contribute to the chemosensitivity and prognosis of acute myeloid leukemia.

SOHO State of the Art Updates and Next Questions: Pre-emptive Therapy at Molecular Measurable Residual Disease Failure in Acute Myeloid Leukemia

Molecular measurable residual disease (MRD, eg, by real-time quantitative polymerase chain reaction, RT-qPCR), is an integral part of response assessment in acute myeloid leukemia (AML) with established prognostic and evolving therapeutic significance. MRD failure can occur through several pathways (namely MRD persistence at the end of treatment at a high level, MRD progression from a low level or MRD re-emergence during follow up; the latter two constitute MRD relapse as defined by the European Leukemia Net) and is clinically actionable, with survival benefit reported in AML subgroups. Selection of pre-emptive therapy at MRD failure relies upon an integrated clinico-molecular assessment and is subset-specific. In acute promyelocytic leukemia, arsenic trioxide-based regimen for MRD failure following frontline treatment with all-trans-retinoic acid plus chemotherapy represents standard of care, while hypomethylating agents (eg, azacitidine), salvage chemotherapy (eg, FLAG-IDA) and venetoclax-based regimens are effective in NPM1-mutated AML. Specific inhibitors of FLT3 have emerging use in FLT3-mutated AML and are associated with minimal toxicity. Furthermore, immunotherapeutic approaches such as donor lymphocyte infusions and interferon-⍺ are efficacious options in the post-allogeneic-HSCT settings. Enrollment into clinical trials with genomic-guided assignment of pre-emptive therapy at MRD failure should be prioritized. Finally, with the emergence of novel agents (eg, menin inhibitors) and approaches (eg, adoptive cellular and immunological therapy), an exciting future lies ahead where a broad array of highly active pre-emptive therapeutic options will likely be clinically applicable to a wide range of AML subsets.

Criteria for Diagnosis and Molecular Monitoring of NPM1-Mutated AML

NPM1-mutated acute myeloid leukemia (AML) represents the largest molecular subgroup of adult AML. NPM1-mutated AML is recognizable by molecular techniques and immunohistochemistry, which, when combined, can solve difficult diagnostic problems (including identification of myeloid sarcoma and NPM1 mutations outside exon 12). According to updated 2022 European LeukemiaNet (ELN) guidelines, determining the mutational status of NPM1 (and FLT3) is a mandatory step for the genetic-based risk stratification of AML. Monitoring of measurable residual disease (MRD) by qRT-PCR, combined with ELN risk stratification, can guide therapeutic decisions at the post-remission stage. Here, we review the criteria for appropriate diagnosis and molecular monitoring of NPM1-mutated AML.

SIGNIFICANCE

NPM1-mutated AML represents a distinct entity in the 2022 International Consensus Classification and 5th edition of World Health Organization classifications of myeloid neoplasms. The correct diagnosis of NPM1-mutated AML and its distinction from other AML entities is extremely important because it has clinical implications for the management of AML patients, such as genetic-based risk stratification according to 2022 ELN. Monitoring of MRD by qRT-PCR, combined with ELN risk stratification, can guide therapeutic decisions at the post-remission stage, e.g., whether or not to perform allogeneic hematopoietic stem cell transplantation.