Complete Remission with Devimistat (CPI-613) in Refractory Burkitt Lymphoma

Introduction: Patients (pts) with primary refractory or relapsed high-grade lymphoma (HGL) including Burkitt lymphoma (BL) and high-grade B-cell lymphoma with rearrangements of MYC and BCL2 and/or BCL6 (double-hit lymphoma, DHL) have a dismal prognosis with patients almost never achieving a meaningful remission to second line therapy. No standard second line therapeutic approach exists, particularly for BL. The characteristic hallmark of these diseases is a dysregulated MYC oncogene with both downstream effects on proliferation and a high metabolic fluxes which use tricarboxylic acid (TCA) cycle intermediates as biosynthetic precursors. CPI-613 (devimistat) is a non-redox active analogue of lipoic acid, a required cofactor for two key mitochondrial enzymes of the TCA cycle, pyruvate dehydrogenase and alpha ketoglutarate dehydrogenase. Disruption of mitochondrial function by CPI-613 results in a shutdown of ATP and biosynthetic-intermediate production, leading to cancer cell death by apoptosis or necrosis. In the initial phase I trial (n=26) one patient with multiply refractory BL had a partial remission sustained for over one year and then consolidated by surgical resection. She remains alive 7 years later. As of July 2021, 20 clinical studies for various cancers have been conducted (ongoing/completed) with devimistat with over 700 patients having received study drug. We initiated a phase II trial to further explore efficacy in HGL. Devimistat has FDA orphan status for BL and 4 other cancers. Methods: NCT03793140 is a multicenter study aiming to enroll 17 patients on each of two cohorts, BL and DHL, with a Simon's 2-stage design for each cohort, requiring one response among the first 9 treated patients to expand to 17. Patients must have had at least one prior line of therapy or are refusing standard of care and must be more than 3 months after a prior stem cell transplant. Active central nervous system (CNS) parenchymal disease is excluded, but prior leptomeningeal disease is allowed if the CSF is negative for more than 4 weeks at enrollment and maintenance intrathecal therapy is ongoing. Devimistat is given by central line over 2 hours daily x 5 days for two 14-day cycles and then as maintenance x5 days every 21 days. Pts were evaluable for response if they received at least 4 infusions over 5 days of the first cycle. Results: 9 pts were enrolled in the DHL/THL arm. Mediannumber of prior therapies were 3 (range, 1-6). No responses were seen, with only 1 patient achieving stable disease as best response, resulting in cohort closure. Thus far, 8 BL pts were enrolled. Median number of prior therapies was 3 (range, 2-4). Two patients were inevaluable for response. 1/6 patients had stable disease through cycle 7 and one had a complete response (CR). This CR patient (HIV+) with 4 prior therapies entered the study with only a biopsy proven thigh mass. He was not a transplant candidate for social reasons. He had a near complete metabolic remission after 4 cycles of devimistat and a CR after cycle 7. (Table and Figure) As of July 2021, he is in cycle 11, having had a 4-week treatment delay of cycle 5 due to CoVID 19 infection. ECOG improved from 3 to 0. Adverse events (AE): As of July30, 2021, no patient experienced a serious adverse event related to study drug. Four patients had grade 3 events at least possibly related: 2 neutropenia, 1 thrombocytopenia and 1 elevated bilirubin. 1 patient had a dose reduction for grade 2 alanine aminotransferase increase. Conclusions: Although our results are preliminary, the complete remission in this patient is promising in a disease where no viable treatment options exist in the relapsed, refractory BL. Enrollment to the BL cohort is ongoing. Figure 1 Figure 1. Disclosures Nikolaenko: Pfizer: Research Funding; Rafael Pharmaceuticals: Research Funding. Pardee: Celgene/BMS: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Pharmacyclics: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees; CBM Biopharma: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Research Funding; Rafael Pharmaceuticals: Research Funding. Abramson: Genentech: Consultancy; Kymera: Consultancy; Karyopharm: Consultancy; AbbVie: Consultancy; Seagen Inc.: Research Funding; Allogene Therapeutics: Consultancy; Astra-Zeneca: Consultancy; Incyte Corporation: Consultancy; BeiGene: Consultancy; Bluebird Bio: Consultancy; Genmab: Consultancy; EMD Serono: Consultancy; Bristol-Myers Squibb Company: Consultancy, Research Funding; C4 Therapeutics: Consultancy; Morphosys: Consultancy; Kite Pharma: Consultancy; Novartis: Consultancy. Horwitz: Vividion Therapeutics: Consultancy; Shoreline Biosciences, Inc.: Consultancy; Tubulis: Consultancy; Verastem: Research Funding; ONO Pharmaceuticals: Consultancy; Myeloid Therapeutics: Consultancy; SecuraBio: Consultancy, Research Funding; Trillium Therapeutics: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Millennium /Takeda: Consultancy, Research Funding; Kura Oncology: Consultancy; Janssen: Consultancy; Kyowa Hakko Kirin: Consultancy, Research Funding; Forty Seven, Inc.: Research Funding; Daiichi Sankyo: Research Funding; C4 Therapeutics: Consultancy; Celgene: Research Funding; Aileron: Research Funding; Affimed: Research Funding; Acrotech Biopharma: Consultancy; ADC Therapeutics: Consultancy, Research Funding. Matasar: GlaxoSmithKline: Honoraria, Research Funding; Teva: Consultancy; Janssen: Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; Genentech, Inc.: Consultancy, Honoraria, Research Funding; Merck Sharp & Dohme: Current holder of individual stocks in a privately-held company; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; IGM Biosciences: Research Funding; Merck: Consultancy; Juno Therapeutics: Consultancy; TG Therapeutics: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Research Funding; Memorial Sloan Kettering Cancer Center: Current Employment; Pharmacyclics: Honoraria, Research Funding; Daiichi Sankyo: Consultancy; ImmunoVaccine Technologies: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Rocket Medical: Consultancy, Research Funding. Noy: Rafael Parhma: Research Funding; Morphosys: Consultancy; Targeted Oncology: Consultancy; Medscape: Consultancy; Pharmacyclics: Consultancy, Research Funding; Janssen: Consultancy, Honoraria; Epizyme: Consultancy. OffLabel Disclosure: CPI-613 (devimistat) is a non-redox active analogue of lipoic acid, a required cofactor for two key mitochondrial enzymes of the TCA cycle, pyruvate dehydrogenase and alpha ketoglutarate dehydrogenase. Disruption of mitochondrial function by CPI-613 results in a shutdown of ATP and biosynthetic-intermediate production, leading to cancer cell death by apoptosis or necrosis

The Mystery of Extramitochondrial Proteins Lysine Succinylation

Lysine succinylation is a post-translational modification which alters protein function in both physiological and pathological processes. Mindful that it requires succinyl-CoA, a metabolite formed within the mitochondrial matrix that cannot permeate the inner mitochondrial membrane, the question arises as to how there can be succinylation of proteins outside mitochondria. The present mini-review examines pathways participating in peroxisomal fatty acid oxidation that lead to succinyl-CoA production, potentially supporting succinylation of extramitochondrial proteins. Furthermore, the influence of the mitochondrial status on cytosolic NAD+ availability affecting the activity of cytosolic SIRT5 iso1 and iso4—in turn regulating cytosolic protein lysine succinylations—is presented. Finally, the discovery that glia in the adult human brain lack subunits of both alpha-ketoglutarate dehydrogenase complex and succinate-CoA ligase—thus being unable to produce succinyl-CoA in the matrix—and yet exhibit robust pancellular lysine succinylation, is highlighted.

The Role of the Rare Variants in the Genes Encoding the Alpha-Ketoglutarate Dehydrogenase in Alzheimer’s Disease

There is increasing evidence that several mitochondrial abnormalities are present in the brains of patients with Alzheimer’s disease (AD). Decreased alpha-ketoglutarate dehydrogenase complex (αKGDHc) activity was identified in some patients with AD. The αKGDHc is a key enzyme in the Krebs cycle. This enzyme is very sensitive to the harmful effect of reactive oxygen species, which gives them a critical role in the Alzheimer and mitochondrial disease research area. Previously, several genetic risk factors were described in association with AD. Our aim was to analyze the associations of rare damaging variants in the genes encoding αKGDHc subunits and AD. The three genes (OGDH, DLST, DLD) encoding αKGDHc subunits were sequenced from different brain regions of 11 patients with histologically confirmed AD and the blood of further 35 AD patients. As a control group, we screened 134 persons with whole-exome sequencing. In all subunits, a one–one rare variant was identified with unknown significance based on American College of Medical Genetics and Genomics (ACMG) classification. Based on the literature research and our experience, R263H mutation in the DLD gene seems likely to be pathogenic. In the different cerebral areas, the αKGDHc mutational profile was the same, indicating the presence of germline variants. We hypothesize that the heterozygous missense R263H in the DLD gene may have a role in AD as a mild genetic risk factor.

Assembly of the [4Fe–4S] cluster of NFU1 requires the coordinated donation of two [2Fe–2S] clusters from the scaffold proteins, ISCU2 and ISCA1

NFU1, a late-acting iron–sulfur (Fe–S) cluster carrier protein, has a key role in the pathogenesis of the disease, multiple mitochondrial dysfunctions syndrome. In this work, using genetic and biochemical approaches, we identified the initial scaffold protein, mitochondrial ISCU (ISCU2) and the secondary carrier, ISCA1, as the direct donors of Fe–S clusters to mitochondrial NFU1, which appears to dimerize and reductively mediate the formation of a bridging [4Fe–4S] cluster, aided by ferredoxin 2. By monitoring the abundance of target proteins that acquire their Fe–S clusters from NFU1, we characterized the effects of several novel pathogenic NFU1 mutations. We observed that NFU1 directly interacts with each of the Fe–S cluster scaffold proteins known to ligate [2Fe–2S] clusters, ISCU2 and ISCA1, and we mapped the site of interaction to a conserved hydrophobic patch of residues situated at the end of the C-terminal alpha-helix of NFU1. Furthermore, we showed that NFU1 lost its ability to acquire its Fe–S cluster when mutagenized at the identified site of interaction with ISCU2 and ISCA1, which thereby adversely affected biochemical functions of proteins that are thought to acquire their Fe–S clusters directly from NFU1, such as lipoic acid synthase, which supports the Fe–S-dependent process of lipoylation of components of multiple key enzyme complexes, including pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase and the glycine cleavage complex.

Abstract 476: Cardiac Adaptation to the Oncometabolite D-2-hydroxyglutarate is Driven by Alpha-Ketoglutarate and Acetyl-CoA

Metabolic reprogramming is a hallmark in both cancer and heart failure. Mutations of the isocitrate deyhydrogenase (IDH) 1 and 2 cause metabolic dysfunction in cancer cells through overproduction of the oncometabolite D-2-hydroxyglutarate (D2-HG) and are associated with cardiomyopathy. We recently discovered that alpha-Ketoglutarate dehydrogenase inhibition by D2-HG redirects Krebs cycle flux. This implies a central role for IDH and ATP citrate lyase (ACL) in regulating reductive formation of citrate and histone acetylation in response to mitochondrial impairment in heart and skeletal muscle. Elucidating how metabolic rewiring promotes changes in gene expression and remodeling in heart muscle holds the promise for development of metabolic strategies to support the failing heart. We tested whether modulation of ACL activity reverses D2-HG-mediated metabolic changes using adult rat ventricular cardiomyocytes and L6 myocytes. The ACL inhibitor BMS303141 (BMS) decreased ATP provision in cultured myocytes in a concentration-dependent manner. There was an inverse relation between alpha-KG and ACL activities. Conversely, co-culture with both BMS (0.5 μM) and D2-HG (1 mM) increased ATP provision suggesting that ACL inhibition in presence of D2-HG may be beneficial for energy provision. Next, we conducted isolated working rat heart perfusions with BMS (0.5 μM) and/or D2-HG (1 mM). Cardiac power rapidly declined (by 25%) in the presence of BMS or D2-HG. Simultaneous perfusion with D2-HG and BMS improved cardiac power, suggesting that ACL inhibition protects the heart from metabolic dysfunction by D2-HG. Further, D2-HG elevation mediated structural remodeling in the heart by activating authophagy through increased acetylation of p300, increased phosphorylation of AMPK, and a corresponding decrease in activation and phosphorylation of mTOR. Parallel tracer studies using labeled glucose and glutamine allowed us to conduct computational flux rate analysis by applying the metabolic network CardioNet. We identified major metabolic pathways that are up- and downregulated by D2-HG. Our findings suggest an “oncometabolic axis” in the heart and underscore the potential application of ACL inhibitors to protect the heart from failing.