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Monoclonal antibodies (daratumumab, anti-CD38; elotuzumab, anti-SLAMF7) and BCMA-targeting T-cell redirecting therapies are highly effective in a large proportion of multiple myeloma (MM) patients. Nonetheless, age, prior (chemo)therapy, and the tumor-microenvironment may impair immune effector cell function and therefore significantly reduce the efficacy of these immunotherapies. Alternatively, an appealing strategy would be the use of targeted therapies, such as immunoconjugates, that directly kill the tumor cells. TAK-169, a novel CD38-specific immunotoxin armed with a deimmunized (DI) Shiga-like toxin A subunit (SLTA) payload, has been designed with this idea. TAK-169 induces irreversible ribosome inactivation of target cells with no dependency on immune effector cells. Prior studies showed that TAK-169 exerts potent cytotoxic activity against CD38-positive human MM cell lines in vitro and in xenograft mouse models (Willert et al. AACR 2019 Abstract 2384). Also, TAK-169 was well tolerated in mice and non-human primates (Willert et al. AACR 2019 Abstract 2384), and deimmunizing the SLTA molecule significantly reduced the in vivo immunogenicity of the payload (Willert et al. AACR 2015 Abstract 2477; Rajagopalan et al. AACR 2016 Abstract 595; Robinson et al. AACR 2017 Abstract 2695). We now assessed the preclinical activity of TAK-169 on a large panel of primary MM cells present in bone marrow (BM) samples from newly diagnosed (ND) (n=13), daratumumab-naive relapsed/refractory (RR) (n=11), and daratumumab-refractory (DR) RR (n=12) patients in flow cytometry-based cytotoxicity assays. In these samples, we also tested the impact of TAK-169 on non-malignant CD38-expressing hematopoietic cells, to gain insight into its on-target off-tumor effects. TAK-169 effectively lysed MM cells present in 36/36 BM samples in a dose-dependent fashion (Figure 1A; median maximal lysis 89%; range 45-100%; EC50: 36pM). Of note, MM cells from ND and daratumumab-naïve RR patients were equally sensitive to TAK-169-mediated lysis (Figure 1B and 1C; median maximal lysis 90%; range 76-100% vs. median maximal lysis 91%; range 76-98%). While MM cells from DR RR patients were also effectively killed, a fraction of these samples was less sensitive to TAK-169-mediated lysis (Figure 1B and 1C; median maximal lysis 66%, range 45-99%). We are currently exploring the impact of several patient and tumor characteristics, such as previous therapies and surface CD38 expression levels on MM cells, on the cytotoxic activity of TAK-169, and results will be reported. In the BM samples, the cytotoxic activity of TAK-169 was mainly restricted to MM cells - except for limited lysis of NK cells (median maximal lysis: 18%) and monocytes (median maximal lysis: 21%), no other non-malignant hematopoietic cells were lysed (Figure 1D), indicating a favorable therapeutic window generated by targeting CD38 with TAK-169. In conclusion, we show that TAK-169 induces powerful lysis of primary MM cells from both ND and RR MM patients, including those refractory to daratumumab. Our findings support the ongoing phase 1 clinical trial evaluating TAK-169 monotherapy in heavily pretreated MM (NCT04017130), and encourage preclinical evaluation of TAK-169 in other CD38-positive malignancies such as AML and T-ALL. Disclosures Higgins: Molecular Templates, Inc.: Current Employment, Other: Stockholder. Willert:Molecular Templates, Inc.: Current Employment, Other: Stockholder. Newcomb:Takeda Pharmaceuticals International: Current Employment, Other: Stockholder. Dash:Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Current Employment, Other: Stockholder. Van De Donk:BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; AMGEN: Membership on an entity's Board of Directors or advisory committees, Research Funding; Servier: Membership on an entity's Board of Directors or advisory committees. Zweegman:Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Mutis:Gadeta: Research Funding; Onkimmune: Research Funding; Takeda: Research Funding; Janssen Pharmaceuticals: Research Funding; Genmab: Research Funding.

Background CD38 is highly expressed on MM cells, hence anti-CD38 agents are of interest as a therapeutic approach in MM. The anti-CD38 monoclonal antibody, dara, as mono- or combination therapy, has substantially improved efficacy outcomes in RRMM, including in heavily pretreated pts. However, many pts relapse and new therapeutic approaches are needed, particularly for pts R/R to dara. TAK-169 is a dimeric fusion protein of an anti-CD38 antibody single chain variable fragment fused to a modified Shiga-like toxin-A subunit. Its unique mechanism of action involves specific binding to CD38+ cells, forced internalization into the target cells, retrograde transport to the cytosol, and irreversible, enzymatic inactivation of target cell ribosomes to cause apoptosis. TAK-169 showed potent, rapid in vitro activity on CD38-expressing cell lines and in vivo efficacy in MM mouse xenograft tumor models with a wide CD38 expression range when administered intravenously (IV) once weekly (QW) or once every 2 weeks (Q2W). Activity was also shown in ex vivo assays from 6 pt bone marrow aspirate (BMA) samples, including from a dara-resistant pt (EC50 5 nM). TAK-169 retained in vitro activity in the presence of dara with modest shifts in EC50 noted at higher dara concentrations. In contrast to dara, TAK-169 has direct tumor cell kill activity that is independent of a pt's immune function status and may therefore be effective in a dara-resistant setting. Accordingly, this phase 1 study will assess safety, tolerability, preliminary efficacy, pharmacokinetics (PK) and pharmacodynamics (PD) of TAK-169 in RRMM. Methods This first-in-human, multicenter, open-label study (NCT04017130; Figure) comprises dose escalation (Part 1) and expansion (Part 2). Eligible pts must be aged ≥18 years with a confirmed diagnosis of MM. Pts enrolled in Part 1 should not be candidates for available therapies known to confer clinical benefit in RRMM. In part 2, pts enrolled should have received ≥3 prior lines of therapy, or ≥2 if one included a PI and IMiD combined. Prior anti-CD38 therapy (including dara) is permitted, except in the Part 2 anti-CD38 therapy-naive expansion cohort. In Part 1, the primary objective is to assess safety/tolerability of TAK-169 in pts with RRMM, and determine maximum tolerated dose/recommended Phase 2 dose (MTD/RP2D). Secondary objectives include efficacy, PK, PD and immunogenicity of TAK-169. Approximately 60 pts are planned to be enrolled to receive IV TAK-169 QW on Days 1/8/15/22 in 28-day cycles. Dosing will start at 50 μg/kg, with subsequent dose levels of 100, 200, 335, 500, 665 μg/kg. A 2nd Q2W dose escalation cohort may be initiated, starting at the QW MTD. The Bayesian Logistic Regression Model with overdose control will be used for dose escalation cohort 2 and for all subsequent dose escalation cohorts, and other non-DLT-safety, clinical, PK, and PD data will be considered. In Part 2, the primary objective is preliminary evaluation of TAK-169 clinical activity in RRMM. Secondary objectives include further evaluating safety, efficacy, PK, PD, and immunogenicity of TAK-169. Part 2 will enroll approximately 54 pts into dara RR (QW and Q2W dosing) and anti-CD38 therapy-naïve (QW dosing) cohorts. TAK-169 will be administered at the MTD/RP2D (QW and Q2W) determined in Part 1. Response will be monitored longitudinally using orthogonal approaches. M-protein levels in serum and urine will be measured each cycle to determine objective responses by International Myeloma Working Group (IMWG) criteria. Minimal residual disease status in pts suspected to be at complete response will be assessed. Circulating free DNA (cfDNA) will be collected from longitudinal plasma samples for disease monitoring. Baseline cytogenetic data will be collected, and TAK-169 efficacy will be assessed in pts with high-risk cytogenetics. Serial blood samples will be used to characterize PK and PD of TAK-169 after IV administration, and to assess the presence of antidrug antibodies. BMA samples collected at screening will be used to evaluate baseline expression of candidate biomarkers. Toxicity will be evaluated using National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) version 5. Efficacy analyses will use descriptive statistics with a 95% confidence interval and the Kaplan-Meier method. PK parameters and immunogenicity status will be summarized using descriptive statistics. Recruitment is ongoing. Figure Disclosures Kumar: Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Takeda: Research Funding. Cornell:Takeda: Consultancy; KaryoPharm: Consultancy. Landgren:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Other: IDMC; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Theradex: Other: IDMC; Adaptive: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Ailawadhi:Cellectar: Research Funding; Pharmacyclics: Research Funding; Janssen: Consultancy, Research Funding; Celgene: Consultancy; Amgen: Consultancy, Research Funding; Takeda: Consultancy. Higgins:Molecular Templates, Inc.: Employment, Equity Ownership. Willert:Molecular Templates: Employment. Waltzman:Molecular Templates, Inc.: Employment, Equity Ownership. Lin:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment, Equity Ownership. Zhang:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Lublinsky:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Dash:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Hanley:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Manoharan:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Leichter:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Ottinger:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Labotka:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Newcomb:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment, Equity Ownership. Vorog:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. OffLabel Disclosure: TAK-169 is a dimeric fusion protein of an anti-CD38 antibody single chain variable fragment fused to a modified Shiga-like toxin-A subunit

Advances in the treatment of multiple myeloma have been driven by the development of new modalities, including proteasome inhibitors, immunomodulatory agents and monoclonal antibodies. TAK-169 is an engineered toxin body (ETB) comprising a proprietarily engineered, deimmunized form of the ribosome inactivating Shiga-like toxin A-subunit (SLTA) genetically fused to an antibody fragment that specifically targets the CD38 cell surface receptor. Although CD38 is a poorly internalizing receptor, TAK-169 is able to efficiently internalize and directly kill CD38-expressing cells through the enzymatic and irreversible inhibition of protein synthesis. This novel mechanism of action may be relevant in patients who have progressed after or are unlikely to respond to CD38-targeted antibody therapy. A library of unique CD38-targeting antibodies fused to deimmunized SLTA was screened in a variety of efficacy and safety models to identify TAK-169. TAK-169 demonstrated potent cytotoxicity across a range of myeloma cell lines with a range of CD38 expression in vitro as well as in patient-derived samples including with previous exposure to daratumumab. TAK-169 retains activity in whole blood and PBMCs, indicating that the presence of red blood cells is not restrictive to cytotoxicity. Furthermore, TAK-169 retains activity in the presence of excess approved, CD38 targeted therapeutic daratumumab. TAK-169 is efficacious in several myeloma xenograft models, both subcutaneous and disseminated. Complete regressions were observed using both a once-weekly and bi-weekly schedule. In addition, a syngeneic model cell line expressing human CD38 was shown to be responsive to TAK-169 treatment in an immunocompetent mouse model, suggesting the possibility of immune mediated cell death induced by TAK-169. Tolerability studies in non-human primates demonstrate that repeat administration is tolerated at doses expected to be efficacious. Takeda Pharmaceuticals and Molecular Templates jointly discovered TAK-169 and are co-developing the molecule for the treatment of multiple myeloma. TAK-169 is expected to enter clinical studies in 2019. Citation Format: Erin K. Willert, Garrett L. Robinson, Jack P. Higgins, Jensing Liu, Janice Lee, Sakeena Syed, Yuhong Zhang, Dan Tavares, Anya Lublinsky, Nibedita Chattopadhyay, Haiqing Wang, Laura Packer, Pu Shi, Carole Harbison, Sanjay Patel, John Newcomb. TAK-169, an exceptionally potent CD38 targeted engineered toxin body, as a novel direct cell kill approach for the treatment of multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2384.

Electrocoagulation, an electrochemical technique used to remove heavy metals from wastewaters, was explored in relation to its potential to remove copper from distillery waste streams. An initial laboratory-scale study demonstrated that copper in spent lees could be reduced by up to 95% using electrocoagulation. Copper could not be removed from caustic washwater, as passivation of the electrodes meant that no floc was formed. However, the washwaters could be treated if mixed with spent lees, with an 80% reduction in copper being obtained. The electrocoagulation system was scaled up and its performance evaluated in a trial at a large Scotch malt whisky distillery. Copper reductions of 88% were achieved at low power consumption (34 W h/m3), while at 112 W h/m3 residual copper levels were reduced by 96%. This trial was carried out at a flow rate of 1000 L/h, demonstrating that the technology could readily handle the volumes and flow rates required in practice. Both the capital and running costs of an electrocoagulation system are low, while the technique presents other advantages over the existing copper removal technologies currently in use in the distilled spirits sector. Copyright © 2014 The Institute of Brewing & Distilling

Tankyrase (TNKS) is a poly-ADP-ribosylating protein (PARP) whose activity suppresses cellular axin protein levels and elevates β-catenin concentrations, resulting in increased oncogene expression. The inhibition of tankyrase (TNKS1 and 2) may reduce the levels of β-catenin-mediated transcription and inhibit tumorigenesis. Compound 1 is a previously described moderately potent tankyrase inhibitor that suffers from poor pharmacokinetic properties. Herein, we describe the utilization of structure-based design and molecular modeling toward novel, potent, and selective tankyrase inhibitors with improved pharmacokinetic properties (39, 40).

Aberrant activation of the Wnt pathway is believed to drive the development and growth of some cancers. The central role of CK1γ in Wnt signal transduction makes it an attractive target for the treatment of Wnt-pathway dependent cancers. We describe a structure-based approach that led to the discovery of a series of pyridyl pyrrolopyridinones as potent and selective CK1γ inhibitors. These compounds exhibited good enzyme and cell potency, as well as selectivity against other CK1 isoforms. A single oral dose of compound 13 resulted in significant inhibition of LRP6 phosphorylation in a mouse tumor PD model.

The lymphocyte-specific kinase (Lck), a member of the Src family of cytoplasmic tyrosine kinases, is expressed in T cells and natural killer (NK) cells. Genetic evidence, including knockout mice and human mutations, demonstrates that Lck kinase activity is critical for normal T cell development, activation, and signaling. Selective inhibition of Lck is expected to offer a new therapy for the treatment of T-cell-mediated autoimmune and inflammatory disease. With the aid of X-ray structure-based analysis, aminopyrimidine amides 2 and 3 were designed from aminoquinazolines 1, which had previously been demonstrated to exhibit potent inhibition of Lck and T cell proliferation. In this report, we describe the synthesis and structure-activity relationships of a series of novel aminopyrimidine amides 3 possessing improved cellular potency and selectivity profiles relative to their aminoquinazoline predecessors 1. Orally bioavailable compound 13b inhibited the anti-CD3-induced production of interleukin-2 (IL-2) in mice in a dose-dependent manner (ED 50 = 9.4 mg/kg).

The lymphocyte-specific kinase (Lck) is a cytoplasmic tyrosine kinase of the Src family expressed in T cells and natural killer (NK) cells. Genetic evidence in both mice and humans demonstrates that Lck kinase activity is critical for signaling mediated by the T cell receptor (TCR), which leads to normal T cell development and activation. Selective inhibition of Lck is expected to offer a new therapy for the treatment of T-cell-mediated autoimmune and inflammatory disease. Screening of our kinase-preferred collection identified aminoquinazoline 1 as a potent, nonselective inhibitor of Lck and T cell proliferation. In this report, we describe the synthesis and structure-activity relationships of a series of novel aminoquinazolines possessing in vitro mechanism-based potency. Optimized, orally bioavailable compounds 32 and 47 exhibit anti-inflammatory activity (ED(50) of 22 and 11 mg/kg, respectively) in the anti-CD3-induced production of interleukin-2 (IL-2) in mice.

Background: The lymphocyte-specific kinase Lck is a member of the Src family of non-receptor tyrosine kinases. Lck catalyzes the initial phosphorylation of T-cell receptor components that is necessary for signal transduction and T-cell activation. On the basis of both biochemical and genetic studies, Lck is considered an attractive cell-specific target for the design of novel T-cell immunosuppressants. To date, the lack of detailed structural information on the mode of inhibitor binding to Lck has limited the discovery of novel Lck inhibitors. Results: We report here the high-resolution crystal structures of an activated Lck kinase domain in complex with three structurally distinct ATP-competitive inhibitors: AMP-PNP (a non-selective, non-hydrolyzable ATP analog); staurosporine (a potent but non-selective protein kinase inhibitor); and PP2 (a potent Src family selective protein tyrosine kinase inhibitor). Comparison of these structures reveals subtle but important structural changes at the ATP-binding site. Furthermore, PP2 is found to access a deep, hydrophobic pocket near the ATP-binding cleft of the enzyme; this binding pocket is not occupied by either AMP-PNP or staurosporine. Conclusions: The potency of staurosporine against Lck derives in part from an induced movement of the glycine-rich loop of the enzyme upon binding of this ligand, which maximizes the van der Waals interactions present in the complex. In contrast, PP2 binds tightly and selectively to Lck and other Src family kinases by making additional contacts in a deep, hydrophobic pocket adjacent to the ATP-binding site; the amino acid composition of this pocket is unique to Src family kinases. The structures of these Lck complexes offer useful structural insights as they demonstrate that kinase selectivity can be achieved with small-molecule inhibitors that exploit subtle topological differences among protein kinases.

The insulin-like growth factor-1 receptor (IGF-1R) plays an important role in the regulation of cell growth and differentiation, and in protection from apoptosis. IGF-1R has been shown to be an appealing target for the treatment of human cancer. Herein, we report the synthesis, structure-activity relationships (SAR), X-ray cocrystal structure and in vivo tumor study results for a series of 2,4-bis-arylamino-1,3-pyrimidines.

N-3-(Phenylcarbamoyl)arylpyrimidine-5-carboxamides are a novel class of selective Lck inhibitors. This series of compounds derives its selectivity from a hydrogen bond with the gatekeeper Thr316 of the enzyme. X-ray co-crystal structural data, structure-activity relationships, and the synthesis of these inhibitors are reported herein.

The lymphocyte-specific kinase (Lck) is a cytoplasmic tyrosine kinase of the Src family expressed in T cells and NK cells. Genetic evidence in both mice and humans demonstrates that Lck kinase activity is critical for signaling mediated by the T cell receptor (TCR), which leads to normal T cell development and activation. A small molecule inhibitor of Lck is expected to be useful in the treatment of T cell-mediated autoimmune and inflammatory disorders and/or organ transplant rejection. In this paper, we describe the synthesis, structure-activity relationships, and pharmacological characterization of 2-aminopyrimidine carbamates, a new class of compounds with potent and selective inhibition of Lck. The most promising compound of this series, 2,6-dimethylphenyl 2-((3,5-bis(methyloxy)-4-((3-(4-methyl-1-piperazinyl)propyl)oxy)phenyl)amino)-4-pyrimidinyl(2,4-bis(methyloxy)phenyl)carbamate (43) exhibits good activity when evaluated in in vitro assays and in an in vivo model of T cell activation.