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  • 1
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    Abstract 287: BAY 1816032, a novel BUB1 kinase inhibitor with potent antitumor activity
    American Association for Cancer Research (AACR) ; 2017
    In:  Cancer Research Vol. 77, No. 13_Supplement ( 2017-07-01), p. 287-287
    Details
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 77, No. 13_Supplement ( 2017-07-01), p. 287-287
    Abstract: The spindle assembly checkpoint represents a highly conserved surveillance mechanism which safeguards correct chromosome segregation by delaying anaphase onset until all chromosomes are properly bi-oriented on the spindle apparatus. Non-catalytic functions of the mitotic kinase BUB1 (budding uninhibited by benzimidazoles 1) were reported to be essential for spindle assembly checkpoint activation. In contrast, the catalytic function of BUB1 plays a minor role in spindle assembly checkpoint activation but is required for chromosome arm resolution and positioning of the chromosomal passenger complex for resolution of spindle attachment errors. Here, we disclose for the first time the structure and functional characterization of a novel, first-in-class Bub1 kinase inhibitor. Medicinal chemistry efforts resulted in BAY 1816032 featuring high potency, long target residence time and good oral bioavailablity. It inhibits BUB1 enzymatic activity with an IC50 of 7 nanomol/L, shows slow dissociation kinetics resulting in a long target residence time of 87 min, and an excellent selectivity on a panel of 395 kinases. Mechanistically BAY 1816032 abrogated nocodazole-induced Thr-120 phosphorylation of the major BUB1 target protein histone H2A in HeLa cells with an IC50 of 29 nanomol/L, induced lagging chromosomes and mitotic delay. Persistent lagging chromosomes and missegregation were observed upon combination with low concentrations of paclitaxel. Single agent BAY 1816032 inhibited proliferation of various tumor cell lines with a median IC50 of 1.4 micromol/L and demonstrated synergy or additivity with paclitaxel or docetaxel in almost all cell lines evaluated (minimal combination index 0.3). In tumor xenograft studies BAY 1816032 only marginally inhibited tumor growth as single agent upon oral administration, however, upon combination with paclitaxel or docetaxel a strong and statistically significant reduction of tumor size as compared to the respective monotherapy was observed. Intratumoral levels of phospho-Thr120 H2A were found to be strongly reduced, and no hints on drug-drug interactions were found. In line with the good tolerability in xenograft studies, no relevant findings from non-GLP 2 weeks toxicological studies in rat and dog were reported. Our findings validate the innovative concept of interference with mitotic checkpoints and justify clinical proof of concept studies evaluating BUB1 inhibitor BAY 1816032 in combination with taxanes in order to enhance their efficacy and potentially overcome resistance. Citation Format: Gerhard Siemeister, Anne Mengel, Wilhelm Bone, Jens Schröder, Sabine Zitzmann-Kolbe, Hans Briem, Amaury E. Fernández-Montalván, Simon Holton, Ursula Mönning, Oliver von Ahsen, Sandra Johanssen, Arwed Cleve, Marion Hitchcock, Kirstin Meyer, Franz von Nussbaum, Michael Brands, Dominik Mumberg, Karl Ziegelbauer. BAY 1816032, a novel BUB1 kinase inhibitor with potent antitumor activity [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 287. doi:10.1158/1538-7445.AM2017-287
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    URL: Article
    DOI: 10.1158/1538-7445.AM2017-287
    RVK:
    XA 36000
    RVK:
    XA 10000
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2017
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  • 2
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    Abstract 2389: Role of MET in head and neck cancer
    American Association for Cancer Research (AACR) ; 2018
    In:  Cancer Research Vol. 78, No. 13_Supplement ( 2018-07-01), p. 2389-2389
    Details
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 78, No. 13_Supplement ( 2018-07-01), p. 2389-2389
    Abstract: Introduction c-MET is a well-known target due to its amplification and overexpression in gastric cancer and NSCLC. Overexpression has also been reported for Head and Neck Cancer (HNSCC), but initial clinical trials with MET inhibitors in HNSCC have not been successful. Methods We investigated the expression level of MET in HNSCC and also characterized the molecular activity level based on the phosphorylation of the intracellular adaptor protein docking site, Tyrosine-1349. In a second larger cohort, we tested expression of MET and correlate it with follow-up data in order to test the prognostic relevance of MET expression in gastric cancer. All clinical samples were all obtained in compliance with clinical regulations and informed consent of every patient. Results We found MET clearly overexpressed in HNSCC. However, the signaling activity of MET was not elevated compared to normal adjacent tissue. To test the relevance of MET for growth of HNSCC cells, we tested the activity of BAY 853474 in a panel of HNSCC cell lines. In contrast to gastric cancer control cell lines which had low nanomolar IC50 values, none of the 12 HNSCC cell lines was sensitive to MET inhibition. This was in contrast to their sensitivity to Cisplatin/Fluoruracil as positive control. Compared to MET dependent cell lines from gastric cancer, HNSCC cell lines had 10 fold less MET expression. The phosphorylation was two orders of magnitude below that of responder cell lines. On the molecular level, we also compared the properties of the HNSCC cell lines with that of fresh frozen tumor biopsies from 50 patients. In this analysis, it became evident that clinical samples had strikingly lower MET expression and phosphorylation even compared to the HNSCC cell lines. Based on these findings, a clinical response to MET inhibitors cannot be expected. In a larger cohort of several hundred patients, we are currently testing whether the elevated MET expression may still be prognostic for progression and/or survival. It appears possible that MET expression may give a growth advantage to tumor cells although it is clearly not fulfilling the criteria for an oncogenic driver in this indication. The significant overexpression of MET in tumor tissue and the very strong overexpression in cell lines compared to clinical samples show that MET expression gives a selective advantage to the tumor cells. We will show whether this advantage results in shorter time to progression or overall survival. Conclusion We show that MET expression in HNSCC cell lines is not representative for the clinical situation. HNSCC does not overexpress Met and the molecular activity is low. MET is devalidated as therapeutic target in HNSCC. An analysis of the prognostic value of MET expression in HNSCC will follow and presented at the AACR meeting in 2018. Citation Format: Thomas Schlange, Martin Khan, Sami Khaznadar, arndt schmitz, Thomas Krahn, Oliver von Ahsen. Role of MET in head and neck cancer [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 2389.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    URL: Article
    DOI: 10.1158/1538-7445.AM2018-2389
    RVK:
    XA 36000
    RVK:
    XA 10000
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2018
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  • 3
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    Abstract 1771: BAY 1834942 is an immunotherapeutic antibody blocking the novel immune checkpoint regulator CEACAM6 (CD66c)
    American Association for Cancer Research (AACR) ; 2018
    In:  Cancer Research Vol. 78, No. 13_Supplement ( 2018-07-01), p. 1771-1771
    Details
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 78, No. 13_Supplement ( 2018-07-01), p. 1771-1771
    Abstract: CEACAM6 (CD66c) was previously shown to act as a novel immune checkpoint regulator suppressing the activity of effector T cells against tumors (Witzens-Harig et al., Blood 2013). CEACAM6 is a GPI-linked protein that is strongly expressed at the tumor cell surface in multiple cancer indications such as non-small cell lung adenocarcinoma (NSCLC), colorectal carcinoma (CRC), gastric adenocarcinoma and pancreatic cancer. In general, elevated CEACAM6 expression is associated with advanced tumor stages and poor prognosis. In vitro experiments showed that engagement of T-cells with CEACAM6, either expressed on tumor cells or presented on beads, resulted in suppression of TCR-mediated T-cell activation and ZAP70 phosphorylation. Based on these findings, we hypothesized that antibodies targeting CEACAM6 may be employed to enhance T-cell responses against CEACAM6-expressing cancers. Here we report the generation and characterization of BAY 1834942, a humanized monoclonal antibody selectively blocking the inhibitory impact of CEACAM6 on human T cells. There is no rodent ortholog of CEACAM6 precluding in vivo efficacy studies. In tumor cell / T cell co-culture systems, BAY 1834942 increased secretion of T-cell cytokines and effector molecules (e.g. IFNγ, TNFα, IL-2, granzyme B) and resulted in improved tumor cell killing. The effects of BAY 1834942 were dose-dependent, only observed in the context of CEACAM6-expressing tumor cells and could be reproduced in experiments using tumor cell lines and T-cell preparations from different sources, including T cells derived from tumor infiltrating lymphocytes from pancreatic cancer. BAY 1834942 is cross-reactive with the cynomolgus CEACAM6 ortholog and was well-tolerated in monkey toxicology studies. In summary, BAY 1834942 is a novel checkpoint inhibitor with potential for the treatment of patients with CEACAM6 expressing cancers, both as single agent and in combination with other checkpoint inhibitors. First-in-man trials are expected to commence in 2018. Citation Format: Joerg Willuda, Mark Trautwein, Jessica Pinkert, Wolf-Dietrich Doecke, Hans-Henning Boehm, Florian Wessel, Yingzi Ge, Eva Maria Gutierrez, Joerg Weiske, Christoph Freiberg, Uwe Gritzan, Julian Glueck, Dieter Zopf, Sven Golfier, Oliver von Ahsen, Ruprecht Zierz, Sabine Wittemer-Rump, Heiner Apeler, Ziegelbauer Karl, Rienk Offringa, Bertolt Kreft, Beckhove Philipp. BAY 1834942 is an immunotherapeutic antibody blocking the novel immune checkpoint regulator CEACAM6 (CD66c) [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 1771.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    URL: Article
    DOI: 10.1158/1538-7445.AM2018-1771
    RVK:
    XA 36000
    RVK:
    XA 10000
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2018
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  • 4
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    Abstract 5445: Preclinical anti-tumor efficacy of an anti-C4.4a (LYPD3) antibody drug conjugate for the treatment of lung squamous cell carcinoma
    American Association for Cancer Research (AACR) ; 2014
    In:  Cancer Research Vol. 74, No. 19_Supplement ( 2014-10-01), p. 5445-5445
    Details
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 74, No. 19_Supplement ( 2014-10-01), p. 5445-5445
    Abstract: C4.4a (LYPD3) has been identified previously as a cancer- and metastasis-associated internalizing cell surface protein. Targeting C4.4a with a specific antibody-drug conjugate (ADC) represents an unique opportunity to treat tumors with high unmet medical need such as squamous cell carcinomas SCC, in particular lung SCC. We have generated an anti-C4.4a ADC consisting of a fully human monoclonal antibody linked to a non cell-permeable tubulin-binding auristatin cytotoxic agent (technology licensed from Seattle Genetics). In vitro, anti-C4.4a ADC showed an anti-proliferative efficacy (IC50) in the nanomolar range in cell lines endogenously expressing C4.4a (e.g. human lung cancer cell lines NCI-H292 and NCI-H322). High ADC stability and selectivity was observed in transfected A549 lung cancer cells over-expressing C4.4a compared to mock-transfected cells. In vivo, anti-C4.4a ADC exhibited a potent and selective antitumor activity in various human xenograft models (NCI-H292, NCI-H322, SCC-4) as well as in two SCC (Lu7433, Lu7343) and one pleomorphic (Lu7064) patient-derived lung cancer xenograft models. The in vivo efficacy is strictly target-dependent and selective as no efficacy was observed in C4.4a negative models (Fadu, Lu 7700) or using a non-specific isotype antibody ADC (NCI-H292, NCI-H322). A minimal effective dose (MED) as low as 1.9 mg/kg, response rates of up to 100%, and additive anti-tumor efficacy in combination with cisplatin were observed in the NCI-H292 xenograft model. Furthermore, it has been demonstrated that NCI-H292 were still sensitive to ADC treatment when tumors were allowed to regrow after the initial treatment cycle(). The anti-C4.4a ADC, which is fully cross-reactive with the mouse orthologue of C4.4a, was well tolerated at efficacious doses. Reversible skin reddening was observed only at doses markedly higher than the MED. In summary, anti-C4.4a ADC is a promising therapeutic candidate for the treatment of C4.4a-expressing squamous cell carcinomas, andpreclinical development has been initiated. Citation Format: Joerg Willuda, Lars Linden, Hans-Georg Lerchen, Charlotte Kopitz, Sven Golfier, Ute Bach, Joachim Schumacher, Beatrix Stelte-Ludwig, Oliver Von Ahsen, Claudia Schneider, Frank Dittmer, Rudolf Beier, Sherif El-Sheik, Jan Tebbe, Gabriele Leder, Heiner Apeler, Rolf Jautelat, Bertolt Kreft, Karl Ziegelbauer. Preclinical anti-tumor efficacy of an anti-C4.4a (LYPD3) antibody drug conjugate for the treatment of lung squamous cell carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5445. doi:10.1158/1538-7445.AM2014-5445
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    URL: Article
    DOI: 10.1158/1538-7445.AM2014-5445
    RVK:
    XA 36000
    RVK:
    XA 10000
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2014
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  • 5
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    Abstract 2786: EGFR expression and phosphorylation in HNSCC predict response to EGFR inhibition but cell lines are not representative for the clinical situation
    American Association for Cancer Research (AACR) ; 2017
    In:  Cancer Research Vol. 77, No. 13_Supplement ( 2017-07-01), p. 2786-2786
    Details
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 77, No. 13_Supplement ( 2017-07-01), p. 2786-2786
    Abstract: Introduction Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer. Survival rates have not been improved for decades and conventional therapy is effective in only 50% of the patients. Based on broad expression in up to 80-90% of the HNSCC cases, epidermal growth factor receptor emerged as drug target but clinical efficacy of EGFR inhibitors in HNSCC is very limited. We therefore reinvestigated the EGFR expression levels necessary for response in cell lines and clinical samples. Methods Standard procedures were used for IHC. The antibody clone D38B1 was used in 1:900 dilution for 2h at RT. Stainings were performed using the DAKO Envision system. EGFR expression and phosphorylation of Tyrosine-1173 were analysed by MSD (Mesoscale Discovery) in lysates from fresh frozen tumor or exponentially growing cells. For proliferation assays, 2000 cells per well were grown for 24 h before addition of inhibitors. Cell culture was continued for 72 h before testing viability using the CellTiter-Glo® Assay. Results The majority (11/13) of HNSCC cell lines responded to the EGFR inhibitor Erlotinib. EGFR was highly expressed and phosphorylated in the Erlotinib responsive cell lines. Resistant cell lines displayed low level EGFR expression and phosphorylation. However, EGFR expression and phosphorylation in treatment naive clinical samples were significantly below the levels found in responding cell lines. In clinical samples EGFR was not overexpressed on the cellular level. Based on these findings, a clinical response to Erlotinib in HNSCC would not be expected. Conclusion The prognostic value of EGFR expression has been used to argue for EGFR as a relevant target in HNSCC. Although most reviews claim that EGFR is overexpressed in HNSCC, clear data supporting this position are missing. Early studies tested the RNA levels and found the EGFR expression in tumors higher compared to control tissues. Studies using IHC assessed the association of EGFR expression with disease progression, but no comparison to expression in normal mucosa was described. Overexpression was based on percentage of positive cells not on the intensity of expression. We show similar levels of EGFR expression in growing keratinocytes and tumor cells. The often described overexpression only originated from a larger number of EGFR positive cells, not on overexpression on the cellular level. The high expression and functional relevance of EGFR in cell lines proves that EGFR activity is required for survival in cell culture. Our findings lead to the conclusion that this is not representative of the clinical situation. Definition of a response threshold for EGFR expression and clinical verification of this expression level is mandatory for the successful use of a predictive biomarker. Citation Format: Oliver von Ahsen, Sami S. Khaznadar, Martin Khan. EGFR expression and phosphorylation in HNSCC predict response to EGFR inhibition but cell lines are not representative for the clinical situation [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 2786. doi:10.1158/1538-7445.AM2017-2786
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    URL: Article
    DOI: 10.1158/1538-7445.AM2017-2786
    RVK:
    XA 36000
    RVK:
    XA 10000
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2017
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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  • 6
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    Abstract 5200: Preclinical pharmacology of the PSMA-targeted thorium-227 conjugate PSMA-TTC: a novel targeted alpha therapeutic for the treatment of prostate cancer
    American Association for Cancer Research (AACR) ; 2017
    In:  Cancer Research Vol. 77, No. 13_Supplement ( 2017-07-01), p. 5200-5200
    Details
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 77, No. 13_Supplement ( 2017-07-01), p. 5200-5200
    Abstract: Prostate-specific membrane antigen (PSMA, FOLH1) is a type II transmembrane glycoprotein of the M28 peptidase family that acts as a glutamate carboxypeptidase on various substrates. PSMA is well established as a target antigen in prostate cancer due to its high and specific overexpression on the surface of prostate cancer cells at all tumor stages, including metastatic and hormone-refractory disease. Several PSMA targeting antibodies and ligands are currently in clinical development or compassionate use therapeutically or as imaging agents. Targeted alpha therapy (TAT) has an established clinical profile with the successful transition of Ra223, an alpha-particle emitter, from bench to bedside in prostate cancer. Thorium-227 is the immediate precursor for Ra223 via alpha-particle emission. We herein describe the generation of a novel TAT, a high energy, alpha-particle emitting PSMA-targeted thorium-227 conjugate (PSMA-TTC). PSMA-TTC consists of a fully human PSMA targeting IgG1 antibody covalently linked via an amide bond to a chelator moiety (3,2 HOPO), enabling radiolabeling with thorium-227 (227Th). PSMA-TTC was prepared in high radiochemical yield and purity and tested for binding affinity to PSMA target (ELISA) as well as PSMA expressing cell lines (FACS). In vitro cytotoxicity experiments were carried out on prostate CA cell lines with different PSMA levels (from 3.000 to 150.000 mAbs bound/ cell). In vivo biodistribution and anti-tumor efficacy were analyzed after i.v. injection of 100-500 kBq/kg at protein doses of 0.14 mg/kg to mice bearing s.c. prostate cancer xenograft models. Additionally, anti-tumor efficacy was evaluated in a PSMA expressing orthotopic bone xenograft model (LNCaP-Luc) monitored by bioluminescence imaging, micro CT and x-ray. PSMA-TTC retains binding affinities to PSMA target and PSMA positive cancer cells similar to the PSMA antibody. Strong in vitro potency and selectivity of PSMA-TTC was shown on different PSMA positive cells. Biodistribution studies in C4-2 xenografts demonstrated specific tumor uptake of PSMA-TTC with a maximum of 50 % of ID/g at t = 72h post dose administration. Selective significant antitumor efficacy was shown for PSMA-TTC in s.c. prostate CA xenograft models with high (C4-2) and medium/low (22Rv1) PSMA protein levels at doses of 250 and 500 kBq/kg. Furthermore, statistically significant prevention of tumor growth was observed after treatment with PSMA-TTC at a dose of 100 kBq/kg in an orthotopic bone xenograft model (LNCaP-Luc). The promising preclinical antitumor activity of PSMA-TTC supports its development for the treatment of patients with metastatic prostate cancer. Citation Format: Stefanie Hammer, Aasmund Larssen, Christine Ellingsen, Solene Geraudie, Derek Grant, Baard Indrevoll, Oliver von Ahsen, Alexander Kristian, Urs B Hagemann, Jenny Karlsson, Roger M Bjerke, Olav B Ryan, Dominik Mumberg, Bertolt Kreft, Alan Cuthbertson. Preclinical pharmacology of the PSMA-targeted thorium-227 conjugate PSMA-TTC: a novel targeted alpha therapeutic for the treatment of prostate 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 5200. doi:10.1158/1538-7445.AM2017-5200
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    URL: Article
    DOI: 10.1158/1538-7445.AM2017-5200
    RVK:
    XA 36000
    RVK:
    XA 10000
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2017
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
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  • 7
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    Abstract 844: Preclinical activity of PSMA-TTC, a targeted alpha therapeutic in patient-derived prostate cancer models
    American Association for Cancer Research (AACR) ; 2018
    In:  Cancer Research Vol. 78, No. 13_Supplement ( 2018-07-01), p. 844-844
    Details
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 78, No. 13_Supplement ( 2018-07-01), p. 844-844
    Abstract: Targeted alpha therapy (TAT) agents deliver high linear energy transfer (LET) alpha-radiation selectively to tumors. The first TAT to be approved is radium-223 which prolongs overall survival in metastatic castration resistant prostate cancer (mCRPC) patients with symptomatic bone metastasis. Radium-223 shows a selective uptake in newly formed bone matrix such as bone metastasis and binds to hydroxyapatite. The PSMA targeted thorium-227 conjugate PSMA-TTC represents another TAT approach in mCRPC. It consists of a fully human PSMA IgG antibody covalently linked to the chelator moiety (3,2 HOPO). This antibody-chelator conjugate is radiolabeled with thorium-227, which decays with a half-life of 18.7 days to radium-223 via alpha-particle emission. Herein we describe tumor targeting and anti-tumor activity of PSMA-TTC in two PSMA positive patient derived xenograft (PDx) models of prostate cancer with different characteristics. In vivo biodistribution and anti-tumor efficacy were analyzed after i.v. injection of PSMA-TTC at radioactive doses from 75-500 kBq/kg and protein doses of either 0.14 or 0.43 mg/kg to tumor bearing mice. Initially, the PDx model KuCap1 (provided by Prof. O. Ogava, University of Kyoto, Japan), a prostate cancer model resistant to the second generation antiandrogen enzalutamide, was analyzed. In this model PSMA-TTC showed strong dose dependent tumor growth inhibition starting at a single dose of 75 kBq/kg. Moreover, after a single i.v. administration of PSMA-TTC at 300 kBq/kg 9 out of 10 mice (90%) showed either stable disease or tumor regression for at least 33 days after treatment. The observed activity was highly selective, as injection of a radiolabeled control conjugate at 300 kBq/kg showed only limited tumor growth inhibition. Next, PSMA-TTC was tested in the hormone- and enzalutamide-sensitive prostate cancer PDx model ST1273 (South Texas Accelerated Research Therapeutics, San Antonio, Texas). A single i.v. injection of PSMA-TTC resulted in significant tumor accumulation of thorium-227 for more than 3 weeks, whereas a radiolabeled isotype control conjugate did not show tumor uptake. In addition, single i.v. administration of PSMA-TTC showed strong dose dependent anti-tumor activity while limited tumor growth inhibition was observed for a radiolabeled isotype control conjugate. Single doses of either 250 or 500 kBq/kg resulted in a 100 % response rate 4 weeks after treatment, with all animals showing partial or even complete regression of tumor growth. No significant effects on body weight were detected compared to vehicle treated animals. In summary, PSMA-TTC shows strong anti-tumor activity in patient derived prostate cancer models which were either sensitive or resistant to standard of care drugs. These data warrant further clinical investigation of this targeted alpha pharmaceutical investigational agent. Citation Format: Stefanie Hammer, Urs B. Hagemann, Sabine Zitzmann-Kolbe, Aasmund Larsen, Christine Ellingsen, Oliver von Ahsen, Jenny Karlsson, Roger M. Bjerke, Olav B. Ryan, Pascale Lejeune, Hartwig Hennekes, Alan Cuthbertson, Karl Ziegelbauer, Dominik Mumberg. Preclinical activity of PSMA-TTC, a targeted alpha therapeutic in patient-derived prostate cancer 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 844.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    URL: Article
    DOI: 10.1158/1538-7445.AM2018-844
    RVK:
    XA 36000
    RVK:
    XA 10000
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2018
    detail.hit.zdb_id: 2036785-5
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  • 8
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    Abstract 4828: Anti-tumor activity of BAY-943, an anti-IL3RA ADC with a novel KSP inhibitor payload, in CDX and PDX AML models
    American Association for Cancer Research (AACR) ; 2019
    In:  Cancer Research Vol. 79, No. 13_Supplement ( 2019-07-01), p. 4828-4828
    Details
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 79, No. 13_Supplement ( 2019-07-01), p. 4828-4828
    Abstract: Despite recent progress in the treatment of AML, clinical outcomes have improved only minimally over the past three decades. Therefore, novel therapeutic agents with a high therapeutic window and a favorable tolerability profile are urgently needed to improve the therapeutic outcome for AML patients. IL3RA (CD123) is the alpha subunit of the interleukin 3 (IL-3) receptor which regulates proliferation, survival and differentiation of hematopoietic cells. IL3RA is expressed at high frequency, with ~84% of AML cases and 59% of classical Hodgkin lymphoma (cHL) cases being positive. IL3RA is expressed in AML blast and leukemic stem cells (LSCs) but not in hematopoietic stem cells (HSCs). In healthy individuals, the IL3RA expression is restricted to myeloid progenitor cells, plasmacytoid dendritic cells (pDCs), basophils and - at low levels - monocytes and B-lymphocyte subsets. This expression pattern suggests that IL3RA could be a clinically relevant target for an antibody-drug conjugate (ADC) approach in treatment of AML, cHL, and MDS. BAY-943 is a novel antibody-drug conjugate (ADC) consisting of a humanized internalizing anti-IL3RA IgG1 antibody (Ab, EC50 on IL3RA-positive tumor cells in flow cytometry: 2-5 nM) conjugated via lysine residues to a potent proprietary kinesin spindle protein inhibitor (KSPi). The kinesin spindle protein (KSP/Eg5/KIF11) is essential for the proper segregation of duplicated centrosomes during spindle formation in the G2/M phase of the cell cycle, as such it is only active in proliferating cells. In vitro, in a panel of IL3RA-positive AML and HL cell lines, BAY-943 showed potency in the nano- to subnanomolar range. In IL3RA-positive cell line derived (CDX) AML xenograft models (MOLM-13 and MV4-11) and patient-derived xenograft (PDX) models, BAY-943 dosed at 10 mg/kg given Q7Dx increased survival compared to vehicle treated mice. Tumor burden (percentage of human CD45 positive AML cells) was significantly reduced compared to vehicle treated mice. In the subcutaneous IL3RA-positive cHL CDX model HDLM-2, BAY-943 dosed at 5 and 10 mg/kg Q7Dx2 induced complete tumor remission in 12 out of 13 mice. In safety studies in Cynomolgus monkeys, BAY-943 (which is cross-reactive with Cynomolgus IL3RA), up to 20 mg/kg single or 10 mg/kg repeat (QWx3) dose were well tolerated with no signs of thrombocytopenia, neutropenia and no liver toxicity, i.e. adverse events observed with ADCs containing other payload classes. As expected, a transient reduction of IL3RA expressing cell types (basophils, pDCs) was observed. In summary, IL3RA-KSPi-ADC BAY-943 shows efficacy in IL3RA-positive AML and HL models and has a favorable safety profile in monkey repeat dose studies. Overall, the preclinical results support further development of BAY-943 as an innovative approach for the treatment of IL3RA-positive AML. Citation Format: Anette Sommer, Dennis Kirchhoff, Antje M. Wengner, Beatrix Stelte-Ludwig, Hans-Georg Lerchen, Anne-Sophie Rebstock, Oliver von Ahsen, Lisa Dietz, Pascale Buchmann, Sandra Johanssen, Dominik Mumberg, Bertolt Kreft. Anti-tumor activity of BAY-943, an anti-IL3RA ADC with a novel KSP inhibitor payload, in CDX and PDX AML models [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 4828.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    URL: Article
    DOI: 10.1158/1538-7445.AM2019-4828
    RVK:
    XA 36000
    RVK:
    XA 10000
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2019
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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    A miniaturized high-throughput screening assay for fucosyltransferase VII
    Elsevier BV ; 2008
    In:  Analytical Biochemistry Vol. 372, No. 1 ( 2008-01), p. 96-105
    Details
    In: Analytical Biochemistry, Elsevier BV, Vol. 372, No. 1 ( 2008-01), p. 96-105
    Type of Medium: Online Resource
    ISSN: 0003-2697
    URL: Article
    DOI: 10.1016/j.ab.2007.08.029
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2008
    detail.hit.zdb_id: 1461105-3
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  • 10
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    Abstract 3726: Preclinical activity of PSMA-TTC (BAY 2315497) in combination with androgen receptor antagonists in prostate cancer models
    American Association for Cancer Research (AACR) ; 2019
    In:  Cancer Research Vol. 79, No. 13_Supplement ( 2019-07-01), p. 3726-3726
    Details
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 79, No. 13_Supplement ( 2019-07-01), p. 3726-3726
    Abstract: Targeted alpha therapy (TAT) agents are able to deliver high linear energy transfer alpha-radiation selectively to tumors. The PSMA targeted thorium-227 conjugate PSMA-TTC (BAY 2315497) is a TAT approach for mCRPC consisting of a human anti-PSMA antibody covalently linked to the chelator moiety (3,2 HOPO) radiolabeled with the alpha emitter thorium-227. PSMA-TTC has shown strong anti-tumor activity in PSMA-positive prostate cancer models (Hammer et al. AACR 2017/2018). Androgen receptor (AR) antagonists like enzalutamide have been effective in improving overall survival in CRPC patients, however, not all patients respond to these therapies and those responding develop resistance and progression of disease. Herein we evaluate in prostate cancer models combination treatments of PSMA-TTC with enzalutamide and the novel AR antagonist darolutamide, which has recently completed a clinical phase 3 trial. AR antagonists induced PSMA levels in LNCaP and C4-2 prostate cancer cells in vitro resulting in increased sensitivity to growth inhibition by PSMA-TTC. In vivo, the combination of PSMA-TTC with enzalutamide was tested in the hormone- and enzalutamide-sensitive patient-derived prostate cancer model ST1273 (South Texas Accelerated Research Therapeutics, San Antonio, Texas). A single i.v. injection of PSMA-TTC at 250 kBq/kg (0.14 mg/kg) resulted in stable disease in 50% and partial response in 38% of the animals 40 days after dosing. Daily treatment with enzalutamide (30 mg/kg po for 28d) resulted in stable disease in 86% and partial response in 14% of the animals. Combining PSMA-TTC and enzalutamide at the mentioned concentrations achieved tumor reduction in all animals, with partial response in 67% and complete response in 33% of the animals 40 days after start of treatment. No significant adverse effects on body weight were detected compared to vehicle treated animals in any of the groups. Additionally, the combination of PSMA-TTC with darolutamide was tested in the enzalutamide resistant patient-derived prostate cancer model KUCaP-1 (provided by Prof. O. Ogawa, University of Kyoto, Japan). PSMA-TTC monotherapy at 150 kBq/kg (0.43 mg/kg) injected twice at an interim of two weeks resulted in 79% tumor growth inhibition and darolutamide treatment (200 mg daily) achieved 60% tumor growth inhibition compared to vehicle treated animals. The combination of PSMA-TTC with darolutamide increased tumor growth inhibition compared to vehicle to 85% and, importantly, 77% of the animals showed stable disease or partial response until 57 days after start of treatment. In summary, combining PSMA-TTC with AR antagonists shows promising preclinical data in patient-derived prostate cancer models with increased response rates even in an enzalutamide-resistant model. Clinical investigation of this targeted alpha pharmaceutical investigational agent alone and in combination is warranted. Citation Format: Stefanie Hammer, Urs B. Hagemann, Sabine Zitzmann-Kolbe, Aasmund Larsen, Chrstine Ellingsen, Oliver von Ahsen, Jenny Karlsson, Roger M. Bjerke, Olav B. Ryan, Pascale Lejeune, Hartwig Hennekes, Alan Cuthbertson, Dominik Mumberg. Preclinical activity of PSMA-TTC (BAY 2315497) in combination with androgen receptor antagonists in prostate cancer models [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 3726.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    URL: Article
    DOI: 10.1158/1538-7445.AM2019-3726
    RVK:
    XA 36000
    RVK:
    XA 10000
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2019
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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