Increasing chimerism after allogeneic stem cell transplantation is associated with longer survival time.

Donor chimerism after allogeneic stem cell transplantation (allo-SCT) is commonly used to predict overall survival (OS) and disease-free survival (DFS). Because chimerism is observed at 1 or more times after allo-SCT and not at baseline, if chimerism is in fact associated with OS or DFS, then the occurrence of either disease progression or death informatively censors (terminates) the observed chimerism process. This violates the assumptions underlying standard statistical regression methods for survival analysis, which may lead to biased conclusions. To assess the association between the longitudinal post-allo-SCT donor chimerism process and OS or DFS, we analyzed data from 195 patients with acute myelogenous leukemia (n = 157) or myelodysplastic syndrome (n = 38) who achieved complete remission after allo-SCT following a reduced-toxicity conditioning regimen of fludarabine/intravenous busulfan. Median follow-up was 31 months (range, 1.1 to 105 months). Fitted joint longitudinal-survival time models showed that a binary indicator of complete (100%) donor chimerism and increasing percent of donor T cells were significantly associated with longer OS, whereas decreasing percent of donor T cells was highly significantly associated with shorter OS. Our analyses illustrate the usefulness of modeling repeated post-allo-SCT chimerism measurements as individual longitudinal processes jointly with OS and DFS to estimate their relationships.

Broad cross-presentation of the hematopoietically derived PR1 antigen on solid tumors leads to susceptibility to PR1-targeted immunotherapy.

PR1 is a HLA-A2-restricted peptide that has been targeted successfully in myeloid leukemia with immunotherapy. PR1 is derived from the neutrophil granule proteases proteinase 3 (P3) and neutrophil elastase (NE), which are both found in the tumor microenvironment. We recently showed that P3 and NE are taken up and cross-presented by normal and leukemia-derived APCs, and that NE is taken up by breast cancer cells. We now extend our findings to show that P3 and NE are taken up and cross-presented by human solid tumors. We further show that PR1 cross-presentation renders human breast cancer and melanoma cells susceptible to killing by PR1-specific CTLs (PR1-CTL) and the anti-PR1/HLA-A2 Ab 8F4. We also show PR1-CTL in peripheral blood from patients with breast cancer and melanoma. Together, our data identify cross-presentation as a novel mechanism through which cells that lack endogenous expression of an Ag become susceptible to therapies that target cross-presented Ags and suggest PR1 as a broadly expressed tumor Ag.

Canagliflozin review - safety and efficacy profile in patients with T2DM.

Canagliflozin is a sodium glucose-cotransporter (SGLT) receptor inhibitor approved for the treatment of type 2 diabetes mellitus (T2DM). This article reviews the mechanism of action of SGLT-2 receptor inhibitors and the efficacy of canagliflozin as an antidiabetic agent, its cardiovascular and renal benefits, and safety profile. During the development of canagliflozin, Phase II trials showed an improvement in cardiac and renal biomarkers such as blood pressure, body weight, and albuminuria. The large CANVAS program showed that canagliflozin reduced the composite cardiovascular outcome of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke. The CANVAS program also showed a possible benefit of canagliflozin on a renal composite of sustained 40% reduction in estimated glomerular filtration rate, the need for renal replacement therapy, or death from renal causes. The safety profile of canagliflozin has been well characterized, and known side effects such as mycotic genital infections were confirmed in CANVAS. However, an increased risk of amputations was observed in CANVAS that requires further study. Overall, canagliflozin is an effective antidiabetic medication with cardiovascular and likely renal benefits, and with a generally well-tolerated safety profile. Results from the CREDENCE trial will further evaluate the safety and potential renal benefits of canagliflozin in patients with established diabetic nephropathy.

Targeting the Leukemia Antigen PR1 with Immunotherapy for the Treatment of Multiple Myeloma.

Purpose: PR1 is a human leukocyte antigen (HLA)-A2 nonameric peptide derived from neutrophil elastase (NE) and proteinase 3 (P3). We have previously shown that PR1 is cross-presented by solid tumors, leukemia, and antigen-presenting cells, including B cells. We have also shown that cross-presentation of PR1 by solid tumors renders them susceptible to killing by PR1-targeting immunotherapies. As multiple myeloma is derived from B cells, we investigated whether multiple myeloma is also capable of PR1 cross-presentation and subsequently capable of being targeted by using PR1 immunotherapies.Experimental Design: We tested whether multiple myeloma is capable of cross-presenting PR1 and subsequently becomes susceptible to PR1-targeting immunotherapies, using multiple myeloma cell lines, a xenograft mouse model, and primary multiple myeloma patient samples.Results: Here we show that multiple myeloma cells lack endogenous NE and P3, are able to take up exogenous NE and P3, and cross-present PR1 on HLA-A2. Cross-presentation by multiple myeloma utilizes the conventional antigen processing machinery, including the proteasome and Golgi, and is not affected by immunomodulating drugs (IMiD). Following PR1 cross-presentation, we are able to target multiple myeloma with PR1-CTL and anti-PR1/HLA-A2 antibody both in vitro and in vivoConclusions: Collectively, our data demonstrate that PR1 is a novel tumor-associated antigen target in multiple myeloma and that multiple myeloma is susceptible to immunotherapies that target cross-presented antigens. Clin Cancer Res; 24(14); 3386-96. ©2018 AACR.

Cathepsin G Is Expressed by Acute Lymphoblastic Leukemia and Is a Potential Immunotherapeutic Target.

Cathepsin G (CG) is a myeloid azurophil granule protease that is highly expressed by acute myeloid leukemia (AML) blasts and leukemia stem cells. We previously identified CG1 (FLLPTGAEA), a human leukocyte antigen-A2-restricted nonameric peptide derived from CG, as an immunogenic target in AML. In this report, we aimed to assess the level of CG expression in acute lymphoid leukemia (ALL) and its potential as an immunotherapeutic target in ALL. Using RT-PCR and western blots, we identified CG mRNA and protein, respectively, in B-ALL patient samples and cell lines. We also examined CG expression in a large cohort of 130 patients with ALL via reverse-phase protein array (RPPA). Our data show that CG is widely expressed by ALL and is a poor prognosticator. In addition to endogenous expression, we also provide evidence that CG can be taken up by ALL cells. Finally, we demonstrate that patient ALL can be lysed by CG1-specific cytotoxic T lymphocytes in vitro. Together, these data show high expression of CG by ALL and implicate CG as a target for immunotherapy in ALL.

Cancer immunotherapies, their safety and toxicity.

INTRODUCTION: Cancer immunotherapy encompasses a wide range of treatment modalities that harness the anti-tumor effects of the immune system. Some immunotherapies broadly activate the immune system while others precisely target distinct tumor antigens. Because of this heterogeneity, the side effects associated with immunotherapy can be mild and localized or more severe and systemic. AREAS COVERED: Cytokines, adoptive cellular therapies and vaccines are the most commonly used immunotherapies for the treatment of a number of malignancies and have been used for many decades. Checkpoint blockade has recently emerged as a promising immunotherapy. The biggest benefits of immunotherapy have been demonstrated in melanoma, renal cell carcinoma and hematologic malignancies. Emerging data are highlighting the potential for broad applicability of immunotherapy in a number of solid and hematologic malignancies. EXPERT OPINION: Immunotherapies are slowly becoming integrated into the standard of care in cancer treatment. Promising results using immunotherapy have been reported demonstrating complete remissions and cures in many patients with aggressive malignancies. The complexity and cost of engineering and administering of some forms of immunotherapy limit their use to distinct patient populations. High-throughput and cost-effective techniques are being used to broaden the applications of immunotherapy to treat cancer patients.

A novel HLA-A*0201 restricted peptide derived from cathepsin G is an effective immunotherapeutic target in acute myeloid leukemia.

PURPOSE: Immunotherapy targeting aberrantly expressed leukemia-associated antigens has shown promise in the management of acute myeloid leukemia (AML). However, because of the heterogeneity and clonal evolution that is a feature of myeloid leukemia, targeting single peptide epitopes has had limited success, highlighting the need for novel antigen discovery. In this study, we characterize the role of the myeloid azurophil granule protease cathepsin G (CG) as a novel target for AML immunotherapy. EXPERIMENTAL DESIGN: We used Immune Epitope Database and in vitro binding assays to identify immunogenic epitopes derived from CG. Flow cytometry, immunoblotting, and confocal microscopy were used to characterize the expression and processing of CG in AML patient samples, leukemia stem cells, and normal neutrophils. Cytotoxicity assays determined the susceptibility of AML to CG-specific cytotoxic T lymphocytes (CTL). Dextramer staining and cytokine flow cytometry were conducted to characterize the immune response to CG in patients. RESULTS: CG was highly expressed and ubiquitinated in AML blasts, and was localized outside granules in compartments that facilitate antigen presentation. We identified five HLA-A*0201 binding nonameric peptides (CG1-CG5) derived from CG, and showed immunogenicity of the highest HLA-A*0201 binding peptide, CG1. We showed killing of primary AML by CG1-CTL, but not normal bone marrow. Blocking HLA-A*0201 abrogated CG1-CTL-mediated cytotoxicity, further confirming HLA-A*0201-dependent killing. Finally, we showed functional CG1-CTLs in peripheral blood from AML patients following allogeneic stem cell transplantation. CONCLUSION: CG is aberrantly expressed and processed in AML and is a novel immunotherapeutic target that warrants further development.