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Personalized Nanomedicines for Leukemia Patients

Periodic Reporting for period 4 - PNANOMED (Personalized Nanomedicines for Leukemia Patients)

Reporting period: 2020-01-01 to 2020-06-30

Acute myeloid leukemia (AML) is a heterogeneous clonal disorder affecting myeloid hematopoiesis, caused by accumulation of genetic aberrations that result in increased self-renewal and proliferation, a block in differentiation, and reduced apoptosis. Although the majority of AML patients respond well to initial chemotherapy, the disease eventually relapses in the majority of patients, who then require treatments that eradicate the leukemia stem cell. Extensive efforts have been undertaken during the last 30 years to find better treatments. To alleviate the burden this disease is putting on individuals, their families and society in general, we undertook this project to decipher the interdependence of genetic mutations and develop nanoparticle/siRNA formulations to inhibit the network of genes that keeps the leukemic cell alive.

We applied cutting-edge technology to mouse models from primary human AML patients to identify the target proteins that sustain leukemia stem cell self-renewal and to develop effective nanomedicines against these targets. We ued primary AML models to study the functional hierarchy of genetic aberrations and to prioritize potential target molecules. A biobank of human transplantable AML xenografts has been established (WP1) and characterized by state-of-the-art genomic approaches (WP2). Genetic aberrations were reversed by knockdown and gene replacement strategies and functional consequences are being assessed in vivo (WP3). Most advanced nanoparticle/siRNA formulations and preparation tools have been employed to develop leukemia-specific nanomedicines (WP4 and 5). This project contributed to a better understanding of AML biology to develop better treatments for leukemia patients.
The main findings of the PNANOMED project relate to the biology of acute myeloid leukemia (AML) and chronic myelomonocytic leukemia (CMML), the function and targeting of mutant IDH1, and lipid nanoparticle/siRNA formulations as novel therapeutic agents.
We established multiple serially transplantable patient derived xenograft (PDX) models from leukemia patients including three serially transplantable CMML-PDX models with disease related gene mutations that recapitulate the disease in vivo. We identified the combination of azacitidine and trametinib as an effective treatment in NRAS-mutated CMML and proposed its clinical development.

We identified novel biologic functions in leukemia and normal cells relating to the function of ETV6, IDH1, its oncometabolite R-2HG and the fusion gene KMT2A-MLLT3.

We identified, patented and characterized the novel mutant IDH1 inhibitor HMS-101 and showed that IDH1 inhibitors strongly synergize with the hypomethylating chemotherapy azacitidine.
We developed siRNAs that specifically inhibit the fusion oncogenes BCR-ABL, TCF3-PBX1, NUP98-NSD1 and CALM-AF10. We packaged the siRNAs in lipid nanoparticles and treated xenograft AML mice. The target siRNA/LNP formulation improved the survival of the mice and was overall well tolerated. This work provides a new, selective approach for targeting fusion oncogenes, which were previously considered undruggable.
By generating serially transplantable AML and CMML patient-derived mouse models and demonstrating that shRNA screening can be performed in these models in vivo we improved the understanding of these understudied diseases. Our identification of the additive effect of trametinib and azacitidine will stimulate a clinical trial in this indication.

We also developed a novel treatments against rare AML subtypes characterized by fusion genes. This treatment is based on lipid nanoparticles that encapsulate small interfering RNAs, that directly target the oncogene. Our proof of efficacy and tolerability in leukemia models provides the basis for the clinical development of this treatment.