Sir Peter MacCallum Department of Oncology - Research Publications
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ItemHealth economic evidence for the use of molecular biomarker tests in hematological malignancies: A systematic review(WILEY, 2022-06)OBJECTIVES: Molecular biomarker tests can inform the clinical management of genomic heterogeneous hematological malignancies, yet their availability in routine care largely depends on the supporting health economic evidence. This study aims to systematically review the economic evidence for recent molecular biomarker tests in hematological malignancies. METHODS: We conducted a systematic search in five electronic databases for studies published between January 2010 and October 2020. Publications were independently screened by two reviewers. Clinical study characteristics, economic methodology, and results were extracted, and reporting quality was assessed. RESULTS: Fourteen studies were identified, of which half (n = 7; 50%) were full economic evaluations examining both health and economic outcomes. Studies were predominantly conducted in a first-line treatment setting (n = 7; 50%) and adopted a non-lifetime time horizon to measure health outcomes and costs (n = 7; 50%). Five studies reported that companion diagnostics for associated therapies were likely cost-effective for acute myeloid leukemia, chronic myeloid leukemia, diffuse large B-cell lymphoma, and multiple myeloma. Four studies suggested molecular biomarker tests for treatment monitoring in chronic myeloid leukemia were likely cost-saving. CONCLUSIONS: Although there is initial confirmation of the promising health economic results, the present research for molecular biomarker tests in hematological malignancies is sparse with many applications of technological advances yet to be evaluated.
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ItemSingle-cell sequencing demonstrates complex resistance landscape in CLL and MCL treated with BTK and BCL2 inhibitors(ELSEVIER, 2022-01-25)The genomic landscape of resistance to targeted agents (TAs) used as monotherapy in chronic lymphocytic leukemia (CLL) is complex and often heterogeneous at the patient level. To gain insight into the clonal architecture of acquired genomic resistance to Bruton tyrosine kinase (BTK) inhibitors and B-cell lymphoma 2 (BCL2) inhibitors in CLL, particularly in patients carrying multiple resistance mutations, we performed targeted single-cell DNA sequencing of 8 patients who developed progressive disease (PD) on TAs (either class). In all cases, analysis of single-cell architecture revealed mutual exclusivity between multiple resistance mutations to the same TA class, variable clonal co-occurrence of multiple mutations affecting different TAs in patients exposed to both classes, and a phenomenon of multiple independent emergences of identical nucleotide changes leading to canonical resistance mutations. We also report the first observation of established BCL2 resistance mutations in a patient with mantle cell lymphoma (MCL) following PD on sequential monotherapy, implicating BCL2 as a venetoclax resistance mechanism in MCL. Taken together, these data reveal the significant clonal complexity of CLL and MCL progression on TAs at the nucleotide level and confirm the presence of multiple, clonally independent, mechanisms of TA resistance within each individual disease context.
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ItemNo Preview AvailableClonal hematopoiesis, myeloid disorders and BAX-mutated myelopoiesis in patients receiving venetoclax for CLL(AMER SOC HEMATOLOGY, 2022-02-24)The BCL2 inhibitor venetoclax has established therapeutic roles in chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML). As BCL2 is an important determinant of survival of both myeloid progenitor and B cells, we investigated whether clinical and molecular abnormalities arise in the myeloid compartment during long-term continuous venetoclax treatment of CLL in 89 patients (87 with relapsed/refractory CLL). Over a median follow-up of 75 (range 21-98) months, persistent cytopenias (≥1 of neutropenia, thrombocytopenia, anemia) lasting ≥4 months and unrelated to CLL occurred in 25 patients (28%). Of these patients, 20 (80%) displayed clonal hematopoiesis, including 10 with therapy-related myeloid neoplasms (t-MNs). t-MNs occurred exclusively in patients previously exposed to fludarabine-alkylator combination therapy with a cumulative 5-year incidence of 10.4% after venetoclax initiation, consistent with rates reported for patients exposed to fludarabine-alkylator combination therapy without venetoclax. To determine whether the altered myelopoiesis reflected the acquisition of mutations, we analyzed samples from patients with no or minimal bone marrow CLL burden (n = 41). Mutations in the apoptosis effector BAX were identified in 32% (13/41). In cellular assays, C-terminal BAX mutants abrogated outer mitochondrial membrane localization of BAX and engendered resistance to venetoclax killing. BAX-mutated clonal hematopoiesis occurred independently of prior fludarabine-alkylator combination therapy exposure and was not associated with t-MNs. Single-cell sequencing revealed clonal co-occurrence of mutations in BAX with DNMT3A or ASXL1. We also observed simultaneous BCL2 mutations within CLL cells and BAX mutations in the myeloid compartment of the same patients, indicating lineage-specific adaptation to venetoclax therapy.
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ItemNo Preview AvailableOutcomes of patients with CLL sequentially resistant to both BCL2 and BTK inhibition(ELSEVIER, 2021-10-26)Covalent Bruton tyrosine kinase inhibitors (BTKi's) and the B-cell lymphoma 2 (BCL2) inhibitor venetoclax have significantly improved outcomes for patients with chronic lymphocytic leukemia (CLL), especially those with biologically adverse disease. Patients with CLL resistant to their first targeted agent (TA) can be effectively treated with the alternative class. However, relapses are expected with second-line TA therapy, and the clinical challenge of double class-resistant disease is now emerging with increasing frequency. To define the characteristics and outcomes of patients with double class-resistant disease, we retrospectively analyzed 17 patients who developed progressive disease (PD) on both TA classes for CLL (venetoclax, then BTKi, n=12; BTKi, then venetoclax, n = 5). The cohort was heavily pretreated (median lines of prior therapy, 4) and enriched for adverse disease genetics (complex karyotype, 12 of 12 tested [100%]; del(17p)/TP53 mutations, 15 of 17 [88%]). The median time to progression on prior venetoclax was 24 months (range, 6-94 months) and was 25 months (range, 1-55 months) on prior BTKi. Progression on second-line TA was manifest as progressive CLL in 11 patients and as Richter transformation in 6. The median overall survival after progression on second-line TA was 3.6 months (95% confidence interval, 2-11 months). Patients with double class-resistant CLL have a dismal prognosis, representing a group of high unmet need.
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ItemClonal independence of JAK2 and CALR or MPL mutations in comutated myeloproliferative neoplasms demonstrated by single cell DNA sequencing(FERRATA STORTI FOUNDATION, 2021-01)
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ItemCorrelation between a 10-color flow cytometric measurable residual disease (MRD) analysis and molecular MRD in adult B-acute lymphoblastic leukemia(WILEY, 2022-03)BACKGROUND: Measurable residual disease (MRD) monitoring in acute lymphoblastic leukemia (ALL) is an important predictive factor for patient outcome and treatment intensification. Molecular monitoring, particularly with quantitative polymerase chain reaction (qPCR) to measure immunoglobin heavy or kappa chain (Ig) or T-cell receptor (TCR) gene rearrangements, offers high sensitivity but accessibility is limited by expertise, cost, and turnaround time. Flow cytometric assays are cheaper and more widely available, and sensitivity is improved with multi-parameter flow cytometry at eight or more colors. METHODS: We developed a 10-color single tube flow cytometry assay. Samples were subject to bulk ammonium chloride lysis to maximize cell yields with a target of 1 × 106 events. Once normal maturation patterns were established, patient samples were analyzed in parallel to standard molecular monitoring. RESULTS: Flow cytometry was performed on 114 samples. An informative immunophenotype was identifiable in all 22 patients who had a diagnostic sample. MRD analysis was performed on 87 samples. The median lower limits of detection and quantification were 0.004% (range 0.0005%-0.028%) and 0.01% (range 0.001%-0.07%) respectively. Sixty-five samples had concurrent molecular MRD testing, with good correlation (r = 0.83, p < 0.001). Results were concordant in 52 samples, and discordant in 13 samples, including one case where impending relapse was detected by flow cytometry but not Ig/TCR qPCR. CONCLUSIONS: Our 10-color flow cytometric MRD assay provided adequate sensitivity and good correlation with molecular assays. This technique offers rapid and affordable testing in B-ALL patients, including cases where a suitable molecular assay cannot be developed or has reduced sensitivity.
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ItemCharacterisation of immune checkpoints in Richter syndrome identifies LAG3 as a potential therapeutic target(WILEY, 2021-10)Richter syndrome (RS), an aggressive lymphoma occurring in the context of chronic lymphocytic leukaemia/small lymphocytic lymphoma, is associated with poor prognosis when treated with conventional immunochemotherapy, therefore, improved treatments are required. Immune checkpoint blockade has shown efficacy in some B-cell malignancies and modest responses in early clinical trials for RS. We investigated the immune checkpoint profile of RS as a basis to inform rational therapeutic investigations in RS. Formalin-fixed, paraffin-embedded biopsies of RS (n = 19), de novo diffuse large B-cell lymphoma (DLBCL; n = 58), transformed indolent lymphomas (follicular [tFL], n = 16; marginal zone [tMZL], n = 24) and non-transformed small lymphocytic lymphoma (SLL; n = 15) underwent gene expression profiling using the NanoString Human Immunology panel. Copy number assessment was performed using next-generation sequencing. Immunohistochemistry (IHC) for LAG3 and PD-1 was performed. LAG3 gene expression was higher in RS compared to DLBCL (P = 0·0002, log2FC 1·96), tFL (P < 0·0001, log2FC 2·61), tMZL (P = 0·0004, log2FC 1·79) and SLL (P = 0·0057, log2FC 1·45). LAG3 gene expression correlated with the gene expression of human leukocyte antigen Class I and II, and related immune genes and immune checkpoints. IHC revealed LAG3 protein expression on both malignant RS cells and tumour-infiltrating lymphocytes. Our findings support the investigation of LAG3 inhibition to enhance anti-tumour responses in RS.