Calithera (United States)

Background: XLAS is a hereditary disorder marked by progressive kidney dysfunction, hearing loss, and ocular abnormalities. The renal pathology results from structural defects in the glomerular basement membrane caused by mutations in the COL4A5 gene. Lack of delivery technology allowing efficient delivery of a therapeutic transgene expressing full-length Col4a5 in podocytes prevents the development of genetic medicines for XLAS patients. Ultrasound-mediated gene delivery (UMGD) offers a noninvasive, non-viral and targeted approach for transgene delivery to renal cells, presenting a promising strategy for COL4A5 gene replacement therapy in XLAS Methods: UMGD parameters were optimized for efficient transgene delivery to podocytes in both mice and non-human primates (NHPs). A series of non-viral gene therapy constructs encoding codon-optimized COL4A5 sequences under the control of podocyte-specific promoters were engineered. The lead vector was delivered to the kidneys of an XLAS mouse model (G5X) and NHP using UMGD. Safety of the gene delivery approach was assessed using established methods. Results: To evaluate the safety and efficacy of UMGD for renal targeting, a reporter transgene was delivered to mice, resulting in kidney-specific and durable expression that was further enhanced with repeat dosing. Podocyte-specific construct was developed which demonstrated robust full-length COL4A5 expression in primary human podocytes. The vector was successfully delivered to the kidneys of G5X mice using UMGD, resulting in strong transgene expression within the glomeruli. Further refinement of UMGD conditions enabled efficient delivery of the COL4A5 transgene to NHP kidneys, with substantial delivery observed in podocytes. Safety and tolerability assessments confirmed a favorable safety profile. Conclusion: The efficient delivery of a nonviral COL4A5 vector to podocytes in the kidneys of both the XLAS disease model and NHP, combined with the favorable safety profile of UMGD, supports the translational potential of this approach for clinical development in the treatment of XLAS.

Background: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the formation and growth of fluid-filled renal cysts, often leading to kidney failure. The most frequent genetic cause of ADPKD are monogenic mutations in the PKD1 gene. Ultrasound mediated gene delivery (UMGD) is an effective approach for noninvasive targeted transgene delivery into renal cells, enabling the development of a nonviral gene replacement therapy for ADPKD. Methods: Using genetic engineering and screening of next generation DNA payload formats, we developed an optimized DNA construct expressing a full-size PKD1 protein. Transgenic PKD1 expression was assessed in vitro in relevant renal cells. To evaluate the potential of UMGD as a nonviral ADPKD treatment option, we delivered genetic constructs to the cystic kidney of an ADPKD mouse model using proprietary acoustic energy profiles and FDA-approved ultrasound components. Results: Testing multiple variants of codon-optimized full-size PKD1 open reading frame sequences along with proximal tubular epithelial cells-specific promoter enabled robust transgenic PKD1 protein expression in ADPKD cystic cells. SonoThera’s highly optimized and proprietary acoustic energy profiles has enabled the targeted delivery of optimized genetic constructs to the cells of cystic kidneys of an ADPKD mouse model. Conclusion: High levels of tissue-specific transgenic full-length PKD1 expression along with the favorable efficacy and safety profile of ultrasound mediated transgene delivery to the cystic cells in ADPKD kidney supports further translation of this approach into clinical development for the treatment of ADPKD.

<div>Abstract<p>Immune-checkpoint inhibitors and adoptive tumor-infiltrating lymphocyte (TIL) therapies have profoundly improved the survival of patients with melanoma. However, a majority of patients do not respond to these agents, and many responders experience disease relapse. Although numerous innovative treatments are being explored to offset the limitations of these agents, novel therapeutic combinations with immunotherapies have the potential to improve patient responses. In this study, we evaluated the antimelanoma activity of immunotherapy combinations with Telaglenastat (CB-839), a potent glutaminase inhibitor (GLSi) that has favorable systemic tolerance. In <i>in vitro</i> TIL:tumor coculture studies, CB-839 treatment improved the cytotoxic activity of autologous TILs on patient-derived melanoma cells. CB-839 treatment decreased the conversion of glutamine to alpha-ketoglutarate (αKGA) more potently in tumor cells versus TILs in these cocultures. These results suggest that CB-839 may improve immune function in a tumor microenvironment by differentially altering tumor and immune cell metabolism. <i>In vivo</i> CB-839 treatment activated melanoma antigen–specific T cells and improved their tumor killing activity in an immune-competent mouse model of adoptive T-cell therapy. Additionally, the combination of CB-839 with anti-PD1 or anti-CTLA4 antibodies increased tumor infiltration by effector T cells and improved the antitumor activity of these checkpoint inhibitors in a high mutation burden mouse melanoma model. Responsiveness to these treatments was also accompanied by an increase of interferon gamma (IFNγ)–associated gene expression in the tumors. Together, these results provide a strong rationale for combining CB-839 with immune therapies to improve efficacy of these treatments against melanoma.</p></div>

Shortly before I was elected President of ASCO, I attended the 65th birthday party of a current patient. She had been diagnosed 10 years earlier with metastatic breast cancer and hadn't been sure she wanted to move forward with further treatment. With encouragement, she elected to participate in a clinical trial of an investigational drug that is now widely used to treat breast cancer. Happily, here we were, celebrating with her now-married daughters, their husbands, and three beautiful grandchildren, ages 2, 4, and 8. Such is the importance of clinical trials and promising new therapies.Clinical research is about saving and improving the lives of individuals with cancer. It's a continuing story that builds on the efforts of untold numbers of researchers, clinicians, caregivers, and patients. ASCO's Clinical Cancer Advances report tells part of this story, sharing the most transformative research of the past year. The report also includes our latest thinking on the most urgent research priorities in oncology.ASCO's 2020 Advance of the Year-Refinement of Surgical Treatment of Cancer-highlights how progress drives more progress. Surgery has played a fundamental role in cancer treatment. It was the only treatment available for many cancers until the advent of radiation and chemotherapy. The explosion in systemic therapies since then has resulted in significant changes to when and how surgery is performed to treat cancer. In this report, we explore how treatment successes have led to less invasive approaches for advanced melanoma, reduced the need for surgery in renal cell carcinoma, and increased the number of patients with pancreatic cancer who can undergo surgery.Many research advances are made possible by federal funding. With the number of new US cancer cases set to rise by roughly a third over the next decade, continued investment in research at the national level is crucial to continuing critical progress in the prevention, screening, diagnosis, and treatment of cancer.While clinical research has translated to longer survival and better quality of life for many patients with cancer, we can't rest on our laurels. With ASCO's Research Priorities to Accelerate Progress Against Cancer, introduced last year and updated this year, we've identified the critical gaps in cancer prevention and care that we believe to be most pressing. These priorities are intended to guide the direction of research and speed progress.Of course, the effectiveness or number of new treatments is meaningless if patients don't have access to them. High-quality cancer care, including clinical trials, is out of reach for too many patients. Creating an infrastructure to support patients is a critical part of the equation, as is creating connections between clinical practices and research programs. We have much work to do before everyone with cancer has equal access to the best treatments and the opportunity to participate in research. I know that ASCO and the cancer community are up for this challenge.Sincerely,Howard A. "Skip" Burris III, MD, FACP, FASCOASCO President, 2019-2020.

Abstract Many tumor cells utilize the amino acid glutamine to meet the elevated bioenergetic and biosynthetic demands of rapid cell growth. The enzyme glutaminase converts glutamine to glutamate, which is used to fuel the TCA cycle, synthesize amino acids and nucleotides, and balance cellular oxidative stress. We developed CB-839, a potent and orally bioavailable small molecule inhibitor of glutaminase, that blocks production of glutamate and generation of downstream metabolites glutathione, malate and aspartate. Mice treated with CB-839 had decreased levels of nucleotides in their tumors, likely due to glutamine-derived aspartate being required for nucleotide biosynthesis. Consistent with our finding that CB-839 decreases nucleotide pools, CB-839 treatment delayed cancer cells from either entry into S-phase or progression through S-phase. Based on this observation, the ability of CB-839 to synergize with therapies that block cell cycle progression was tested. CB-839 synergized with the CDK4/6 inhibitor palbociclib in colorectal carcinoma (CRC), triple negative breast cancer (TNBC) and ER+ breast cancer cell lines resulting in anti-proliferative activity. The combination of CB-839 with palbociclib also led to decreased cell cycle progression through S-phase and caused an accumulation of cells in G1 as measured by an EdU DNA incorporation assay. In vivo, the combination of CB-839 with palbociclib resulted in enhanced anti-tumor activity in both an ER+ breast cancer and CRC xenograft tumor model. We next investigated whether CB-839 treatment would enhance the anti-tumor effects of DNA repair inhibitors, given the ability of CB-839 treatment to decrease nucleotide pools. CB-839 treatment in combination with the PARP inhibitors niraparib and talazoparib led to synergistic anti-proliferative activity in TNBC, CRC, non-small cell lung carcinoma, ovarian and prostate cancer cells. In vivo, the combination of CB-839 with PARP inhibitors showed enhanced anti-tumor activity compared to single agent treatment in a CRC tumor xenograft model. CB-839 is currently undergoing evaluation for efficacy in the treatment of cancer in several phase I/II clinical trials. These encouraging pre-clinical results support the testing of CB-839 with CDK4/6 or PARP inhibitors in cancer patients. Citation Format: Ethan D. Emberley, Mark Bennett, Jason Chen, Matthew Gross, Tony Huang, Amani Makkouk, Gisele Marguier, Alison Pan, Sandra M. Spurlock, Susanne Steggerda, Francesco Parlati. The glutaminase inhibitor CB-839 synergizes with CDK4/6 and PARP inhibitors in pre-clinical tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3509.

Abstract Cancer cells exhibit increased use of nutrients including glucose and glutamine to support the bioenergetic and biosynthetic demands of proliferation. We tested CB-839, a small molecule inhibitor of glutaminase that impairs glutamine utilization, in combination with erlotinib on EGFR mutant non- small cell lung cancer (NSCLC) as a therapeutic strategy to simultaneously impair cancer glucose and glutamine utilization and thereby suppress tumor growth. Here we show that CB-839 synergizes with erlotinib to drive energetic stress and activate the AMPK pathway in EGFR (del19) lung tumors. Tumor cells undergo metabolic crisis and cell death resulting in rapid tumor regression in vivo in mouse NSCLC xenografts. Consistently, positron emission tomography (PET) imaging with 18F- fluoro-2-deoxyglucose (18F-FDG) and 11C-Glutamine (11C-Gln) of xenografts indicated reduced glucose and glutamine uptake in tumors following CB-839 + erlotinib treatment. Therefore, PET imaging with 18F-FDG and 11C-Gln can be used to non-invasively monitor tumor metabolic and therapeutic response to CB-839 and erlotinib combination therapy. Note: This abstract was not presented at the meeting. Citation Format: Milica Momcilovic, Sean T. Bailey, Jason T. Lee, Daniel Braas, Thomas G. Graeber, Melissa Works, Francesco Parlati, Susan Demo, Tonya C. Walser, Steven M. Dubinett, Saman Sadeghi, Heather Christofk, David B. Shackelford. Targeted inhibition of EGFR and glutaminase induces metabolic crisis in EGFR mutant lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1830. doi:10.1158/1538-7445.AM2017-1830

Abstract Triple negative breast cancer (TNBC) cell lines are highly dependent on glutamine (Gln) for growth and survival. A critical step in Gln utilization is its conversation to glutamate (Glu) by the mitochondrial enzyme glutaminase (GLS). CB-839 is a potent inhibitor of GLS that has anti-proliferative activity in TNBC cell lines and antitumor activity in TNBC xenograft models (Gross et al., Mol. Cancer Ther. 13:890). Across a panel of breast cancer cell lines derived from both receptor positive and TNBC tumors, sensitivity to CB-839 was associated with (i) elevated GLS expression, (ii) elevated GLS activity, and (iii) the TNBC subtype. Importantly, many of the determinants of CB-839 sensitivity in cell lines are also present in primary tumor samples, including high mRNA and protein expression of GLS and a high Glu to Gln ratio in TNBC tumors as compared to receptor positive tumors. These observations motivate the Phase 1 clinical study of CB-839 in TNBC patients. To aid in the selection of a recommended Phase 2 dose, we sought to develop a pharmacodynamic (PD) assay to directly measure the GLS activity in breast tumor lysates in order to determine the extent of GLS inhibition in tumor biopsies from CB-839 treated patients. To develop a robust PD assay, we first identified conditions that maintain the GLS:CB-839 inhibitory complex during preparation of lysates from CB-839 treated samples. High concentrations of KCl (150 mM) and low concentrations of K-phosphate (15 mM) in the lysis buffer, as well as maintaining the lysate at a low temperature stabilized the inhibited complex. Following gel filtration of the lysate to remove unbound CB-839 and exchange the buffer, GLS activity was immediately measured with a coupled enzyme assay. The GLS activity measured at this step reflects the residual activity present in a sample that was exposed to CB-839. To quantify the amount of total GLS present in the sample, we incubated the same lysate for 3 hours at room temperature under conditions of low KCl and high phosphate to allow the the GLS:CB-839 complex to fully dissociate prior to measuring activity. This assay format allows quantitation of the % GLS inhibition from a single tumor lysate sample and eliminates the requirement for multiple biopsies as well as any assay variability due to tumor heterogeneity. We utilized this tumor PD assay to determine the plasma drug levels required for maximal tumor GLS inhibition in a preclinical TNBC model. Mice bearing HCC1806 TNBC tumors were first treated with a range of CB-839 doses. Four hours after oral administration, a 10 mg/kg dose of CB-839 resulted in >90% inhibition of tumor GLS. CB-839 plasma concentrations of 100 nM corresponded to 50% inhibition of tumor GLS, while maximal inhibition occurred at plasma concentrations ≥300 nM. In xenograft studies, maximal anti-tumor efficacy was achieved with BID dosing at 200 mg/kg, a dose and schedule that resulted in trough plasma levels of CB-839 of ≥300 nM and sustained GLS inhibition in tumors. As part of an ongoing Phase 1 trial, this assay will be utilized to monitor tumor PD responses in TNBC patients undergoing treatment. Citation Format: Andy MacKinnon, Mark Bennett, Ethan Emberley, Mathew Gross, Julie Janes, Evan Lewis, Alison Pan, Mirna Rodriguez, Peter Shwonek, Taotao Wang, Jinfu Yang, Frances Zhao, Francesco Parlati. A novel pharmacodynamic assay to measure glutaminase inhibition following oral administration of CB-839 in triple negative breast cancer biopsies [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-08-07.