High incidence of minor and micro breakpoints in Chronic Myeloid Leukaemia with additional cytogenetic abnormalities at diagnosis - the Western Australian series.

Introduction and objective: Chronic Myeloid Leukaemia (CML) is defined by the presence of the Philadelphia chromosome, a balanced translocation between chromosomes 9 and 22 that results in the constitutively active tyrosine kinase, BCR-ABL1. Additional chromosomal abnormalities (ACAs) at diagnosis occur in 5-10% of CML patients, and are important for prognosis. They are classified as major or minor route. The purpose of our study was to determine the frequency and type of ACAs in 193 newly diagnosed CML patients, and to evaluate patient characteristics, treatment response, and survival. Methods: Medical records, in conjunction with data from the PathWest cytogenetics and molecular laboratories, were analysed. Results: ACAs were present in 14 (7.3%) of patients at diagnosis. Seven patients had major-route abnormalities, with additional chromosome 8 (+8) the most common. All patients were treated with tyrosine kinase inhibitors (TKIs). Three patients presented in blast crisis; two patients have died. Of note, there was a high incidence of the rare minor and micro BCR-ABL1 fusion transcripts. Conclusions: Frequency of ACAs at diagnosis was similar to that of previous reports. These patients consist a higher-risk cohort, and require individualised treatment, with consideration of frontline and secondary TKIs, adjunct chemotherapy, novel agents, and allogeneic stem cell transplant.

Jumping translocation involving chromosome 13q in a patient with Crohn's Disease and inv(16)(p13.1q22)/CBFB-MYH11 acute myeloid leukemia.

Jumping translocations (JT) are rare chromosomal rearrangements caused by the translocation of one donor chromosome segment to two or more recipient chromosomes. In the setting of myeloid neoplasms, JT are typically associated with disease transformation to acute myeloid leukemia (AML), and studies to date have found JT to be associated with poor prognosis and short overall survival. However, JT have been only very rarely reported in AML associated with a favorable AML prognostic cytogenetic marker. Additionally, JT have infrequently been described in hematological malignancies associated with autoimmune diseases (AID) such as Crohn's Disease (CD). Here we describe a case of a 40-year-old female with a 24-year history of CD diagnosed with AML harbouring the inv(16)(p13.1q22)/CBFB-MYH11 rearrangement in conjunction with sideline clones containing trisomy 13, tetrasomy 13, and a JT of chromosome 13q12 jumping to 7q32 and 18p11.2. The patient attained molecular remission one month post diagnosis after induction 7 + 3 chemotherapy. Morphologic relapse of disease occurred 27 months post diagnosis. A second molecular remission was attained 3 months later after re-induction chemotherapy. The patient received a sibling bone marrow transplant 32 months post diagnosis and is currently in remission 7 months post allogeneic transplant. To the best of our knowledge, this case represents the first report of JT occurring in inv(16)(p13.1q22)/CBFB-MYH11 AML and the second of JT occurring in an AML patient with prior clinical history of CD. This case provides further insight into the rare occurrence of JT in AML, particularly AML with a favorable cytogenetic marker in conjunction with AID.

Preclinical Evaluation of Carfilzomib for Infant KMT2A-Rearranged Acute Lymphoblastic Leukemia.

BACKGROUND: Infants with KMT2A-rearranged B-cell precursor acute lymphoblastic leukemia (ALL) have poor outcomes. There is an urgent need to identify novel agents to improve survival. Proteasome inhibition has emerged as a promising therapeutic strategy for several hematological malignancies. The aim of this study was to determine the preclinical efficacy of the selective proteasome inhibitor carfilzomib, for infants with KMT2A-rearranged ALL. METHODS: Eight infant ALL cell lines were extensively characterized for immunophenotypic and cytogenetic features. In vitro cytotoxicity to carfilzomib was assessed using a modified Alamar Blue assay with cells in logarithmic growth. The Bliss Independence model was applied to determine synergy between carfilzomib and the nine conventional chemotherapeutic agents used to treat infants with ALL. Established xenograft models were used to identify the maximal tolerated dose of carfilzomib and determine in vivo efficacy. RESULTS: Carfilzomib demonstrated low IC50 concentrations within the nanomolar range (6.0-15.8 nm) across the panel of cell lines. Combination drug testing indicated in vitro synergy between carfilzomib and several conventional chemotherapeutic agents including vincristine, daunorubicin, dexamethasone, L-asparaginase, and 4-hydroperoxycyclophosphamide. In vivo assessment did not lead to a survival advantage for either carfilzomib monotherapy, when used to treat both low or high disease burden, or for carfilzomib in combination with multi-agent induction chemotherapy comprising of vincristine, dexamethasone, and L-asparaginase. CONCLUSIONS: Our study highlights that in vitro efficacy does not necessarily translate to benefit in vivo and emphasizes the importance of in vivo validation prior to suggesting an agent for clinical use. Whilst proteasome inhibitors have an important role to play in several hematological malignancies, our findings guard against prioritization of carfilzomib for treatment of KMT2A-rearranged infant ALL in the clinical setting.

Patients with multiple myeloma over a large catchment of 2.5 million square kilometres: a Western Australia retrospective survival review.

Multiple myeloma is an incurable malignancy of plasma cells. We retrospectively reviewed the survival outcomes of patients with multiple myeloma in Western Australia (WA) public hospitals over a 10-year period. We did not detect a difference in survival between patients residing the metropolitan Perth and regional areas, despite a paucity of haematology services in regional WA due to low population density in a large geographic area. Patients with R-ISS Stage 3 had the poorest survival in our cohort with median survival of 24 months.