The fundamental interest of the Myeloid Malignancies Section is the detection, prevention and treatment of AML relapse with the long-term objective of using immunotherapy without the need allo-HSCT. Our research over the past year has involved the following four complementary approaches: Functional characterization of the human immune system in AML patients in remission after treatment: In collaboration with the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins and the trans-NIH Center for Human Immunology, Autoimmunity and Inflammation (CHI) we initiated in fall 2012 a clinical protocol (J1293) to study the functional immune capacity of AML patients after completion of chemotherapy. While a variety of active immunization approaches of cancer-vaccination have been previously tested in clinical trials in this population at risk of relapse, our study represents the first attempt at a systematic deep characterization of the functional capacity of the immune systems of these patients. Using the seasonal influenza vaccine as a robust and well defined immunological challenge, information from 15-color flow cytometry panels will be integrated with gene expression profiles, cytokine luminex, T and B cell elispot and antibody titers and correlated with clinical data including time since chemotherapy, complete blood counts and (if applicable) date of influenza infection or eventual AML relapse. An analogous deep immunome analysis of healthy volunteers undergoing influenza vaccination has recently been performed by CHI and may serve as a baseline for this ongoing analysis. Landmarks: Patient enrollment completed. All samples from clinical protocol collected. Laboratory analysis 75% complete. Identification of unique AML leukemia associated antigens: The ability to target myeloid malignancies using immunotherapy, without allogeneic transplantation, depends on the capability to target leukemic clones while sparing normal tissues. It is now possible to generate clinical grade ex-vivo expanded T cells specific for leukemia associated antigens (LAA) for use in adoptive cell therapy. A variety of putative leukemia associated antigens (LAA) for acute myeloid leukemia (AML) have been identified and consensus panels have attempted to prioritize generic cancer antigens but an evidence-based list of AML antigen targets has not yet been established. We therefore analyzed, using a custom quantitative real-time PCR (qRT-PCR) array, gene expression of 65 potential LAAs in de-identified, highly clinically annotated samples from 48 newly diagnosed untreated adult AML patients collected under IRB-approved protocols from three NCCN cancer centers (Johns Hopkins, Vanderbilt and Massachusetts General) and compared with normal donor peripheral blood, bone marrow and organ specific RNA profiles. This showed that the majority of the proposed AML antigens do not have mRNA overexpression in more than 20% of AML patient samples at diagnosis;a list of the top six AML antigens based on gene expression will be submitted for publication shortly. This finding will be extended by 1) quantification of LAA expression in cell populations enriched for leukemia stem cell function and 2) the characterization of MHC presented LAA epitopes using a novel RNA-Seq, immunoprecipitation and proteomics approach. Landmarks: RT-PCR: Laboratory work completed. Presented at American Society of Clinical Oncology annual meeting. Manuscript in preparation. Proteomics: experimental work ongoing. High sensitivity measurement of AML disease burden for patients in remission to stratify based on risk of relapse and to determine efficacy of additional treatment: The ability to 1) risk stratify patients in clinical remission into high and low risks of relapse based on persistence of molecular minimal residual disease (MRD) and 2) quantify the efficacy of any treatment intervention by determination of changes in this MRD would be of significant utility, especially in trials of novel experimental agents such as immunotherapy. Using information derived from our study of AML antigens (above) we have developed a novel molecular panel that may utility in the quantification and surveillance monitoring of MRD in AML patients. Landmarks: Substantial review of MRD in AML performed (PMID: 23799371). Pilot laboratory work performed. Employee Discovery and Invention Report in preparation. Characterization of the disease biology characteristics and immune parameters associated with successful response to immunotherapy: Cancer immunotherapy is associated, at best, with an overall response rate rarely exceeding 50% with a complete response rate in the range 10-20%. Predictive biomarkers of response would be of great interest to the field, both practically for clinical use but also as a route to understanding the fundamental immunobiological mechanisms associated with response. We have therefore begun to study immune parameters and disease characteristics from a variety of patients treated with immunotherapy for myeloid malignancies (CML, MDS, AML) both retrospectively from completed studies (GVAX, alemtuzumab) but also prospectively in future studies (pomalidomide, lenalidomide, ipilimumab, nivolumab, vaccine immunotherapy) in an attempt to elucidate disease and agent specific characteristics but also those features shared across responders. Such analysis may also serve as a benchmark for future trials. Landmarks: Analysis of clinical trial data from NIH trial of alemtuzumab in myelodysplastic syndromes performed (submitted for presentation). Analysis of laboratory data from Levitsky Laboratory (Johns Hopkins) on induced immune response following GVAX-K562 immunization in chronic myeloid leukemia patients performed and published (PMID 24013666). In summary, the primary interest of the Myeloid Malignancies Section is the detection, prevention and treatment of AML relapse with the aim of understanding and using immunotherapy outside of the setting of stem cell transplantation. This involves a coordinated, overlapping and iterative program of translational research on carefully annotated patient samples from informative clinical time-points in an attempt to understand the fundamental human immunobiology associated with successful responses to cancer immunotherapy in patients with myeloid malignancies.
Showing the most recent 10 out of 45 publications
