Leukemia
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Recent advances in antibody technology to harness T cells for cancer immunotherapy, particularly in the difficult-to-treat setting of relapsed/refractory acute lymphoblastic leukemia (r/r ALL), have led to innovative methods for directing cytotoxic T cells to specific surface antigens on cancer cells. One approach involves administration of soluble bispecific (or dual-affinity) antibody-based constructs that temporarily bridge T cells and cancer cells. Another approach infuses ex vivo-engineered T cells that express a surface plasma membrane-inserted antibody construct called a chimeric antigen receptor (CAR). ⋯ With the introduction of these immunotherapies, new challenges arise related to unique toxicities and distinctive pathways of resistance. An increasing body of knowledge is being accumulated on how to predict, prevent, and manage such toxicities, which will help to better stratify patient risk and tailor treatments to minimize severe adverse events. A deeper understanding of the precise mechanisms of action and immune resistance, interaction with other novel agents in potential combinations, and optimization in the manufacturing process will help to advance immunotherapy outcomes in the r/r ALL setting.
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More than one-third of patients with acute myeloid leukemia (AML) harbor aberrant mutations in Fms-like tyrosine kinase 3 (FLT3). Among them, the internal tandem duplication (ITD) mutation predicts poor prognosis. MZH29 is a novel FLT3 inhibitor synthesized in our laboratory that showed that cellular and kinase assays sustained inhibitory effects on wild-type and mutant FLT3, including the FLT3-ITD, FLT3-D835H/Y/V and FLT3-K663Q mutants. ⋯ Oral administration of 10 mg/kg MZH29 caused complete tumor regression and extended survival in a mouse model of AML with less toxicity. Subsequent proteomics study revealed less proteome perturbation in the MZH29-treated group than in the AC220-treated group. MZH29 demonstrates potential and potent novel FLT3 inhibitory effects for the treatment of AML.
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Traditional response criteria in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are based on bone marrow morphology and may not accurately reflect clonal tumor burden in patients treated with non-cytotoxic chemotherapy. We used next-generation sequencing of serial bone marrow samples to monitor MDS and AML tumor burden during treatment with epigenetic therapy (decitabine and panobinostat). Serial bone marrow samples (and skin as a source of normal DNA) from 25 MDS and AML patients were sequenced (exome or 285 gene panel). ⋯ Using an ultrasensitive sequencing approach, we detected extremely rare mutations (equivalent to 1 heterozygous mutant cell in 2000 non-mutant cells) months to years before their expansion at disease relapse. While patients can live with persistent clonal hematopoiesis in a CR or stable disease, ultimately we find evidence that expansion of a rare subclone occurs at relapse or progression. Here we demonstrate that sequencing of serial samples provides an alternative measure of tumor burden in MDS or AML patients and augments traditional response criteria that rely on bone marrow blast percentage.
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Refractory or relapsed acute myeloid leukemia (AML) represents a frequent complication after allogeneic hematopoietic stem-cell transplantation (HSCT). We show herein that primary in vitro stimulation of CD45RA-selected CD4 T cells of stem-cell donors with 10/10 HLA-matched AML blasts results in expansion of cytolytic T-lymphocytes (CTL) that almost all recognize HLA-DPB1 mismatch alleles, which clinically occur in up to 80% of donor-patient pairs. Primary AML blasts were found to strongly express HLA-DPB1, whereas fibroblasts and keratinocytes used as surrogate target cells for graft-versus-host disease did express HLA-DPB1 only upon IFN-γ pre-treatment. ⋯ Short-term stimulated T cell-lines specifically lysed HLA-DPB1 mismatch-expressing AML blasts, but not fibroblasts and keratinocytes without IFN-γ pre-treatment. Notably, these CD4 CTL efficiently eliminated AML blasts upon adoptive transfer into leukemia-engrafted NSG mice. In conclusion, we show strong immunogenicity of HLA-DPB1 mismatch alleles in CD45RA-selected CD4 T cells of stem-cell donors and introduce a novel strategy to reliably generate HLA-DPB1-specific CD4 CTL that might be powerful cellular therapeutics in relapsed or refractory AML after HSCT.
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Randomized Controlled Trial
Impact of prior treatment on patients with relapsed multiple myeloma treated with carfilzomib and dexamethasone vs bortezomib and dexamethasone in the phase 3 ENDEAVOR study.
The randomized phase 3 ENDEAVOR study (N=929) compared carfilzomib and dexamethasone (Kd) with bortezomib and dexamethasone (Vd) in relapsed multiple myeloma (RMM). We performed a subgroup analysis from ENDEAVOR in patients categorized by number of prior lines of therapy or by prior treatment. Median progression-free survival (PFS) for patients with one prior line was 22.2 months for Kd vs 10.1 months for Vd, and median PFS for patients with ⩾2 prior lines was 14.9 months for Kd vs 8.4 months for Vd. ⋯ Overall response rates (Kd vs Vd) were 81.9 vs 65.5% (one prior line), 72.0 vs 59.7% (⩾2 prior lines), 71.2 vs 60.3% (prior bortezomib) and 70.1 vs 59.3% (prior lenalidomide). The safety profile in the prior lines subgroups was qualitatively similar to that in the broader ENDEAVOR population. In RMM, outcomes are improved when receiving treatment with carfilzomib compared with bortezomib, regardless of the number of prior therapy lines or prior exposure to bortezomib or lenalidomide.