Reporting bone marrow biopsies for myelodysplastic neoplasms and acute myeloid leukaemia incorporating WHO 5th edition and ICC 2022 classification systems: ALLG/RCPA joint committee consensus recommendations.

The classification of myeloid neoplasms continues to evolve along with advances in molecular diagnosis, risk stratification and treatment of disease. An approach for disease classification has been grounded in international consensus that has facilitated understanding, identification and management of molecularly heterogeneous entities, as well as enabled consistent patient stratification into clinical trials and clinical registries over time. The new World Health Organization (WHO) and International Consensus Classification (ICC) Clinical Advisory Committee releasing separate classification systems for myeloid neoplasms in 2022 precipitated some concern amongst haematopathology colleagues both locally and internationally. While both classifications emphasise molecular disease classification over the historical use of morphology, flow cytometry and cytogenetic based diagnostic methods, notable differences exist in how morphological, molecular and cytogenetic criteria are applied for defining myelodysplastic neoplasms (MDS) and acute myeloid leukaemias (AML). Here we review the conceptual advances, diagnostic nuances, and molecular platforms required for the diagnosis of MDS and AML using the new WHO and ICC 2022 classifications. We provide consensus recommendations for reporting bone marrow biopsies. Additionally, we address the logistical challenges encountered implementing these changes into routine laboratory practice in alignment with the National Pathology Accreditation Advisory Council reporting requirements for Australia and New Zealand.

How comparable are patient outcomes in the "real-world" with populations studied in pivotal AML trials?

Despite an increasing desire to use historical cohorts as "synthetic" controls for new drug evaluation, limited data exist regarding the comparability of real-world outcomes to those in clinical trials. Governmental cancer data often lacks details on treatment, response, and molecular characterization of disease sub-groups. The Australasian Leukaemia and Lymphoma Group National Blood Cancer Registry (ALLG NBCR) includes source information on morphology, cytogenetics, flow cytometry, and molecular features linked to treatment received (including transplantation), response to treatment, relapse, and survival outcome. Using data from 942 AML patients enrolled between 2012-2018, we assessed age and disease-matched control and interventional populations from published randomized trials that led to the registration of midostaurin, gemtuzumab ozogamicin, CPX-351, oral azacitidine, and venetoclax. Our analyses highlight important differences in real-world outcomes compared to clinical trial populations, including variations in anthracycline type, cytarabine intensity and scheduling during consolidation, and the frequency of allogeneic hematopoietic cell transplantation in first remission. Although real-world outcomes were comparable to some published studies, notable differences were apparent in others. If historical datasets were used to assess the impact of novel therapies, this work underscores the need to assess diverse datasets to enable geographic differences in treatment outcomes to be accounted for.

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.

Observations from a national sample exchange program for molecular haematology testing.

External quality assessment programs (EQAP) for molecular haematology generally only assess the analytical phase of laboratory testing or provide limited evaluation of post-analytical components. We incorporated comprehensive post-analytical evaluation into an existing national inter-laboratory sample exchange program for molecular haematology due to the increasing complexity of diagnostic molecular testing and interpretation. We report key findings from four years of longitudinal data using this approach. Eighteen participating laboratories enrolled in an annual reciprocal sample exchange program from 2019-2022, which covered conventional and next-generation sequencing (NGS) assays. Participants submitted results on their laboratory information system-generated reports which then underwent central review. Reports were assessed according to consensus values and relevant national and international reporting standards and guidelines. A total of 680 reports were received. Laboratories had high concordance in the analytical phase of testing, with incorrect variant detection observed in a total of six of 680 (0.9%) reports. In contrast, post-analytical concordance was much lower, with at least one discordance observed in 28.9-57.6% of all conventional reports and 33.3-100% NGS reports. The most frequent post-analytical discordances were: (1) not including key technical information on reports (total 41.9% conventional, 47.2% NGS); (2) not using standard gene and variant nomenclature (total 28.2% conventional, 25.6% NGS). NGS reports also demonstrated discrepancies in variant classification (total 20.4%) and interpretation (total 10.2%). The rate of discrepancies generally improved year-on-year. Inter-laboratory concordance for molecular haematology testing is high in the analytical phase, however opportunities exist for improvement in the post-analytical phase. Given that result interpretation is crucial for clinical decision-making and that molecular testing is a complex and evolving field, we suggest that EQAPs should comprehensively evaluate both analytical and post-analytical components of laboratory performance in order to harmonise reporting and to support the accurate interpretation of molecular haematology tests.

Venetoclax-based low intensity therapy in molecular failure of NPM1-mutated AML.

ABSTRACT: Molecular failure in NPM1-mutated acute myeloid leukemia (AML) inevitably progresses to frank relapse if untreated. Recently published small case series show that venetoclax combined with low-dose cytarabine or azacitidine can reduce or eliminate measurable residual disease (MRD). Here, we report on an international multicenter cohort of 79 patients treated for molecular failure with venetoclax combinations and report an overall molecular response (≥1-log reduction in MRD) in 66 patients (84%) and MRD negativity in 56 (71%). Eighteen of 79 patients (23%) required hospitalization, and no deaths were reported during treatment. Forty-one patients were bridged to allogeneic transplant with no further therapy, and 25 of 41 were MRD negative assessed by reverse transcription quantitative polymerase chain reaction before transplant. Overall survival (OS) for the whole cohort at 2 years was 67%, event-free survival (EFS) was 45%, and in responding patients, there was no difference in survival in those who received a transplant using time-dependent analysis. Presence of FLT3-ITD mutation was associated with a lower response rate (64 vs 91%; P < .01), worse OS (hazard ratio [HR], 2.50; 95% confidence interval [CI], 1.06-5.86; P = .036), and EFS (HR, 1.87; 95% CI, 1.06-3.28; P = .03). Eighteen of 35 patients who did not undergo transplant became MRD negative and stopped treatment after a median of 10 months, with 2-year molecular relapse free survival of 62% from the end of treatment. Venetoclax-based low intensive chemotherapy is a potentially effective treatment for molecular relapse in NPM1-mutated AML, either as a bridge to transplant or as definitive therapy.

Evaluation of T-cell clonality by anti-TRBC1 antibody-based flow cytometry and correlation with T-cell receptor sequencing.

Flow cytometry (FC) incorporating the T-cell receptor ß constant chain-1 (TRBC1) has been recently proposed as a new standard in T-cell clonality assessment. While early studies demonstrated high sensitivity in samples with conspicuous tumour burden, performance in real-world samples, including those with low tumour burden and correlation with molecular methods has been limited. We evaluated TRBC1-FC performance and correlated the results with high-throughput TRB sequencing and a targeted next-generation sequencing gene panel. Our cohort consisted of 90 evaluable samples from 57 patients. TRBC1-FC confirmed T-cell clonality in 37 out of 38 samples (97%) that were involved in a mature T-cell neoplasm (MTCN). T-cell clonality was also identified in nine samples from patients lacking a current or prior diagnosis of MTCN, consistent with the emerging entity T-cell clonality of uncertain significance. TRBC-FC was polyclonal in all samples and negative for disease involvement by standard pathology assessment. However, correlation with TRB sequencing in 17 of these samples identified two cases that harboured the known clonal sequence from index testing, indicating the presence of measurable residual disease not otherwise detected. Our study provides real-world correlative validation of TRBC1-FC, highlighting the strengths and limitations pertinent to its increasing implementation by general diagnostic laboratories.

Persistence of UBTF tandem duplications in remission in acute myeloid leukaemia.

UBTF tandem duplications are recurrent in adult and paediatric acute myeloid leukaemia and have been reported to be associated with a poor prognosis. Co-mutations in WT1 and FLT3 are common while morphological dysplasia is frequent. The role of UBTF-TDs in leukemogenesis is yet to be elucidated; however they have been proposed as early initiating events, making them attractive for assessment of MRD and a potential therapeutic target. We present two cases where the UBTF-TD was observed in remission and discuss the implications of these findings in the clinicobiological understanding of this emerging entity.

Sorafenib plus intensive chemotherapy in newly diagnosed FLT3-ITD AML: a randomized, placebo-controlled study by the ALLG.

Sorafenib maintenance improves outcomes after hematopoietic cell transplant (HCT) for patients with FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) acute myeloid leukemia (AML). Although promising outcomes have been reported for sorafenib plus intensive chemotherapy, randomized data are limited. This placebo-controlled, phase 2 study (ACTRN12611001112954) randomized 102 patients (aged 18-65 years) 2:1 to sorafenib vs placebo (days 4-10) combined with intensive induction: idarubicin 12 mg/m2 on days 1 to 3 plus either cytarabine 1.5 g/m2 twice daily on days 1, 3, 5, and 7 (18-55 years) or 100 mg/m2 on days 1 to 7 (56-65 years), followed by consolidation and maintenance therapy for 12 months (post-HCT excluded) in newly diagnosed patients with FLT3-ITD AML. Four patients were excluded in a modified intention-to-treat final analysis (3 not commencing therapy and 1 was FLT3-ITD negative). Rates of complete remission (CR)/CR with incomplete hematologic recovery were high in both arms (sorafenib, 78%/9%; placebo, 70%/24%). With 49.1-months median follow-up, the primary end point of event-free survival (EFS) was not improved by sorafenib (2-year EFS 47.9% vs 45.4%; hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.51-1.51; P = .61). Two-year overall survival (OS) was 67% in the sorafenib arm and 58% in the placebo arm (HR, 0.76; 95% CI, 0.42-1.39). For patients who received HCT in first remission, the 2-year OS rates were 84% and 67% in the sorafenib and placebo arms, respectively (HR, 0.45; 95% CI, 0.18-1.12; P = .08). In exploratory analyses, FLT3-ITD measurable residual disease (MRD) negative status (<0.001%) after induction was associated with improved 2-year OS (83% vs 60%; HR, 0.4; 95% CI, 0.17-0.93; P = .028). In conclusion, routine use of pretransplant sorafenib plus chemotherapy in unselected patients with FLT3-ITD AML is not supported by this study.

Efficacy and safety of luspatercept versus epoetin alfa in erythropoiesis-stimulating agent-naive, transfusion-dependent, lower-risk myelodysplastic syndromes (COMMANDS): interim analysis of a phase 3, open-label, randomised controlled trial.

BACKGROUND: Erythropoiesis-stimulating agents (ESAs) are the standard-of-care treatment for anaemia in most patients with lower-risk myelodysplastic syndromes but responses are limited and transient. Luspatercept promotes late-stage erythroid maturation and has shown durable clinical efficacy in patients with lower-risk myelodysplastic syndromes. In this study, we report the results of a prespecified interim analysis of luspatercept versus epoetin alfa for the treatment of anaemia due to lower-risk myelodysplastic syndromes in the phase 3 COMMANDS trial. METHODS: The phase 3, open-label, randomised controlled COMMANDS trial is being conducted at 142 sites in 26 countries. Eligible patients were aged 18 years or older, had a diagnosis of myelodysplastic syndromes of very low risk, low risk, or intermediate risk (per the Revised International Prognostic Scoring System), were ESA-naive, and required red blood cell transfusions (2-6 packed red blood cell units per 8 weeks for ≥8 weeks immediately before randomisation). Integrated response technology was used to randomly assign patients (1:1, block size 4) to luspatercept or epoetin alfa, stratified by baseline red blood cell transfusion burden (<4 units per 8 weeks vs ≥4 units per 8 weeks), endogenous serum erythropoietin concentration (≤200 U/L vs >200 to <500 U/L), and ring sideroblast status (positive vs negative). Luspatercept was administered subcutaneously once every 3 weeks starting at 1·0 mg/kg body weight with possible titration up to 1·75 mg/kg. Epoetin alfa was administered subcutaneously once a week starting at 450 IU/kg body weight with possible titration up to 1050 IU/kg (maximum permitted total dose of 80 000 IU). The primary endpoint was red blood cell transfusion independence for at least 12 weeks with a concurrent mean haemoglobin increase of at least 1·5 g/dL (weeks 1-24), assessed in the intention-to-treat population. Safety was assessed in patients who received at least one dose of study treatment. The COMMANDS trial was registered with ClinicalTrials.gov, NCT03682536 (active, not recruiting). FINDINGS: Between Jan 2, 2019 and Aug 31, 2022, 356 patients were randomly assigned to receive luspatercept (178 patients) or epoetin alfa (178 patients), comprising 198 (56%) men and 158 (44%) women (median age 74 years [IQR 69-80]). The interim efficacy analysis was done for 301 patients (147 in the luspatercept group and 154 in the epoetin alfa group) who completed 24 weeks of treatment or discontinued earlier. 86 (59%) of 147 patients in the luspatercept group and 48 (31%) of 154 patients in the epoetin alfa group reached the primary endpoint (common risk difference on response rate 26·6; 95% CI 15·8-37·4; p<0·0001). Median treatment exposure was longer for patients receiving luspatercept (42 weeks [IQR 20-73]) versus epoetin alfa (27 weeks [19-55]). The most frequently reported grade 3 or 4 treatment-emergent adverse events with luspatercept (≥3% patients) were hypertension, anaemia, dyspnoea, neutropenia, thrombocytopenia, pneumonia, COVID-19, myelodysplastic syndromes, and syncope; and with epoetin alfa were anaemia, pneumonia, neutropenia, hypertension, iron overload, COVID-19 pneumonia, and myelodysplastic syndromes. The most common suspected treatment-related adverse events in the luspatercept group (≥3% patients, with the most common event occurring in 5% patients) were fatigue, asthenia, nausea, dyspnoea, hypertension, and headache; and none (≥3% patients) in the epoetin alfa group. One death after diagnosis of acute myeloid leukaemia was considered to be related to luspatercept treatment (44 days on treatment). INTERPRETATION: In this interim analysis, luspatercept improved the rate at which red blood cell transfusion independence and increased haemoglobin were achieved compared with epoetin alfa in ESA-naive patients with lower-risk myelodysplastic syndromes. Long-term follow-up and additional data will be needed to confirm these results and further refine findings in other subgroups of patients with lower-risk myelodysplastic syndromes, including non-mutated SF3B1 or ring sideroblast-negative subgroups. FUNDING: Celgene and Acceleron Pharma.

Cellular distribution of IDH mutations in AML during morphologic remission.

Limited information exists about the cellular distribution of mutations which persist in remission in acute myeloid leukemia (AML) (variably considered pre-leukemic mutations). We hypothesized that mutations detectable in all cell compartments may be less pathogenic than those that are myeloid-restricted. Here, we describe the cellular compartments that have IDH mutations in five patients with IDH-mutated AML in morphologic remission. Unlike pre-leukemic clones harboring the more common DNMT3A, TET2 and ASXL1 (DTA) mutations, we show that IDH mutations are myeloid-restricted. This finding provides an explanation for the reports that IDH mutations carry a higher risk for relapse than DTA mutations. Detailed analysis of one case also shows acquisition of additional mutations in distinct cellular compartments, illustrating subclonal complexity associated with therapeutics.

Enrichment of BTK Leu528Trp mutations in patients with CLL on zanubrutinib: potential for pirtobrutinib cross-resistance.

The covalent Bruton's tyrosine kinase inhibitors (BTKis) are highly effective for the treatment of chronic lymphocytic leukemia (CLL). The dominant resistance mechanism observed with the BTKi ibrutinib is the development of BTK Cys481 codon mutations. Whether a similar resistance mutation profile exists for the newer-generation, more selective BTKi zanubrutinib is unknown. In samples referred for diagnostic next-generation sequencing in patients with progressive CLL, we observed an enrichment in the kinase-dead BTK Leu528Trp mutation in patients treated with zanubrutinib compared with ibrutinib (54%; 7 of 13 vs 4%; 1 of 24, P = .001). We describe 2 patients with BTK Leu528Trp mutations who showed clinical cross-resistance and progressive enrichment of the BTK Leu528Trp mutation over time when treated with the noncovalent BTKi pirtobrutinib. Both patients subsequently responded to venetoclax-based treatment. In summary, we have identified an enrichment of the BTK Leu528Trp mutation arising in patients treated with zanubrutinib that may impart cross-resistance to the noncovalent inhibitor pirtobrutinib and therefore may have implications for sequencing of these treatments in CLL.

Outcomes following venetoclax-based treatment in therapy-related myeloid neoplasms.

Therapy-related myeloid neoplasms (t-MN) are aggressive malignancies in need of effective therapies. The BCL-2 inhibitor venetoclax represents a paradigm shift in the treatment of acute myeloid leukemia. However, the effectiveness of venetoclax has not been studied in a large cohort of t-MN. We retrospectively analyzed 378 t-MN patients, of which 96 (25.4%, 47 therapy-related acute myeloid leukemia, 1 therapy-related chronic myelomonocytic leukemia, 48 therapy-related myelodysplastic syndrome) received venetoclax. Median interval from t-MN to venetoclax initiation was 2.9 (Interquartile range [IQR] 0.7-12) months, and patients received a median of 3 (IQR 1-4) cycles. The composite complete remission (CRc) rate, median progression-free survival (PFS), and overall survival (OS) were 39.1%, 4.9 months, and 7 months, respectively. The upfront use of venetoclax and achieving CRc were associated with improved survival, whereas the presence of Chromosome 7 abnormalities was associated with an inferior survival. Neither the TP53-status nor the percent bone marrow blast predicted the likelihood of CRc or survival. Paired genetic analysis performed at venetoclax initiation and failure did not show the evidence of the selection of the TP53-mutated clone. In a propensity-matched analysis, the use of venetoclax-based regimen as the first-line therapy was associated with a superior survival compared to hypomethylating agent (HMA)-based first-line therapy (9.4 vs. 6.1 months, p = .01). We conclude that the upfront use of venetoclax with HMA improved survival, though PFS and OS remain poor. As the phenotype at diagnosis or the percent blasts did not predict outcomes, venetoclax should be studied in all t-MN phenotypes.

Treatment-free remission after ceasing venetoclax-based therapy in patients with acute myeloid leukemia.

The clinical benefit of adding venetoclax (VEN) to hypomethylating agents or low-dose cytarabine in older and/or unfit patients with newly diagnosed acute myeloid leukemia (AML) has been confirmed in phase 3 studies. With the increased uptake of VEN-based therapies for patients with AML, a pertinent question is whether treatment can be safely ceased among patients who have achieved sustained remission. We hypothesized that a proportion of patients opting to cease therapy may benefit from a treatment-free remission (TFR) period without indefinite treatment. We report the retrospective outcomes of 29 patients in remission for a minimum of 12 months on VEN-based therapy, with 55% continuing therapy until disease progression and 45% electively ceasing treatment (STOP). With follow-up exceeding 5 years, we observed a median TFR lasting 45.8 months among the STOP cohort, with >50% of patients still in sustained remission at the data cutoff. The risk of relapse and duration of relapse-free and overall survival were similar between the 2 cohorts. Factors favoring sustained TFR within the cohort included NPM1 and/or IDH2 mutation at diagnosis, complete remission without measurable residual disease, and at least 12 months of VEN-based combination therapy prior to treatment cessation.

Panel-based gene testing in myelodysplastic/myeloproliferative neoplasm overlap syndromes: Australasian Leukaemia and Lymphoma Group (ALLG) consensus statement.

This review aims to provide an expert consensus statement to address the role of gene-panel testing in the diagnosis, prognosis and management of adult myelodysplastic syndrome/myeloproliferative neoplasm overlap syndromes (MDS/MPN) in Australia. This consensus statement was developed by an expert group, actively involved in gene panel testing in the area of MDS/MPN in Australia. This work was led by the chairs of the MDS (A/Prof A. Enjeti) and MPN (A/Prof D. Ross) working parties of the Australasian Leukaemia and Lymphoma Group (ALLG). The authors were selected after an expression of interest process on the basis of active laboratory involvement in gene panel testing, a specific demonstrated interest in MDS/MPN and/or publication record in this field. The authors were then allocated sections for literature review to identify the specific genes of interest for each MDS/MPN entity. At least two authors reviewed each section and an overarching diagnostic algorithm was developed by a consensus amongst all authors.