1
|
Blake-Hedges J, Groff D, Foo W, Hanson J, Castillo E, Wen M, Cheung D, Masikat MR, Lu J, Park Y, Carlos NA, Usman H, Fong K, Yu A, Zhou S, Kwong J, Tran C, Li X, Yuan D, Hallam T, Yin G. Production of antibodies and antibody fragments containing non-natural amino acids in Escherichia coli. MAbs 2024; 16:2316872. [PMID: 38381460 PMCID: PMC10883104 DOI: 10.1080/19420862.2024.2316872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/06/2024] [Indexed: 02/22/2024] Open
Abstract
Therapeutic bioconjugates are emerging as an essential tool to combat human disease. Site-specific conjugation technologies are widely recognized as the optimal approach for producing homogeneous drug products. Non-natural amino acid (nnAA) incorporation allows the introduction of bioconjugation handles at genetically defined locations. Escherichia coli (E. coli) is a facile host for therapeutic nnAA protein synthesis because it can stably replicate plasmids encoding genes for product and nnAA incorporation. Here, we demonstrate that by engineering E. coli to incorporate high levels of nnAAs, it is feasible to produce nnAA-containing antibody fragments and full-length immunoglobulin Gs (IgGs) in the cytoplasm of E. coli. Using high-density fermentation, it was possible to produce both of these types of molecules with site-specifically incorporated nnAAs at titers > 1 g/L. We anticipate this strategy will help simplify the production and manufacture of promising antibody therapeutics.
Collapse
|
2
|
Hanson J, Groff D, Carlos A, Usman H, Fong K, Yu A, Armstrong S, Dwyer A, Masikat MR, Yuan D, Tran C, Heibeck T, Zawada J, Chen R, Hallam T, Yin G. An Integrated In Vivo/In Vitro Protein Production Platform for Site-Specific Antibody Drug Conjugates. Bioengineering (Basel) 2023; 10:bioengineering10030304. [PMID: 36978695 PMCID: PMC10045668 DOI: 10.3390/bioengineering10030304] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/14/2023] [Accepted: 02/22/2023] [Indexed: 03/06/2023] Open
Abstract
The XpressCF+® cell-free protein synthesis system is a robust platform for the production of non-natural amino acids containing antibodies, which enable the site-specific conjugation of homogeneous antibody drug conjugates (ADCs) via click chemistry. Here, we present a robust and scalable means of achieving a 50–100% increase in IgG titers by combining the high productivity of cell-based protein synthesis with the unique ability of XpressCF+® reactions to produce correctly folded and assembled IgGs containing multiple non-natural amino acids at defined positions. This hybrid technology involves the pre-expression of an IgG light-chain (LC) protein in a conventional recombinant E. coli expression system, engineered to have an oxidizing cytoplasm. The prefabricated LC subunit is then added as a reagent to the cell-free protein synthesis reaction. Prefabricated LC increases IgG titers primarily by reducing the protein synthesis burden per IgG since the cell free translation machinery is only responsible for synthesizing the HC protein. Titer increases were demonstrated in four IgG products in scales ranging from 100-µL microplate reactions to 0.25-L stirred tank bioreactors. Similar titer increases with prefabricated LC were also demonstrated for a bispecific antibody in the scFvFc-FabFc format, demonstrating the generality of this approach. Prefabricated LC also increases robustness in cell-free reactions since it eliminates the need to fine-tune the HC-to-LC plasmid ratio, a critical parameter influencing IgG assembly and quality when the two IgG subunits are co-expressed in a single reaction. ADCs produced using prefabricated LC were shown to be identical to IgGs produced in cell-free alone by comparing product quality, in vitro cell killing, and FcRn receptor binding assays. This approach represents a significant step towards improving IgG titers and the robustness of cell-free protein synthesis reactions by integrating in vivo and in vitro protein production platforms.
Collapse
|
3
|
Li X, Abrahams C, Yu A, Embry M, Henningsen R, DeAlmeida V, Matheny S, Kline T, Yam A, Stafford R, Hallam T, Lupher M, Molina A. Targeting CD74 in B-cell non-Hodgkin lymphoma with the antibody-drug conjugate STRO-001. Oncotarget 2023; 14:1-13. [PMID: 36634212 PMCID: PMC9836384 DOI: 10.18632/oncotarget.28341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Overexpression of CD74, a type II transmembrane glycoprotein involved in MHC class II antigen presentation, has been reported in many B-cell non-Hodgkin lymphomas (NHLs) and in multiple myeloma (MM). STRO-001 is a site-specific, predominantly single-species antibody-drug conjugate (ADC) that targets CD74 and has demonstrated efficacy in xenograft models of MM and tolerability in non-human primates. Here we report results of preclinical studies designed to elucidate the potential role of STRO-001 in B-cell NHL. STRO-001 displayed nanomolar and sub-nanomolar cytotoxicity in 88% (15/17) of cancer cell lines tested. STRO-001 showed potent cytotoxicity on proliferating B cells while limited cytotoxicity was observed on naïve human B cells. A linear dose-response relationship was demonstrated in vivo for DLBCL models SU-DHL-6 and U2932. Tumor regression was induced at doses less than 5 mg/kg, while maximal activity with complete cures were observed starting at 10 mg/kg. In MCL Mino and Jeko-1 xenografts, STRO-001 starting at 3 mg/kg significantly prolonged survival or induced tumor regression, respectively, leading to tumor eradication in both models. In summary, high CD74 expression levels in tumors, nanomolar cellular potency, and significant anti-tumor in DLBCL and MCL xenograft models support the ongoing clinical study of STRO-001 in patients with B-cell NHL.
Collapse
|
4
|
Abrahams CL, McGeehan A, Smith J, Yuan R, Doshi KA, Zhou S, Li X, Tran C, Yin G, Molina A, Bedard K, Hallam T. Abstract 5591: Anti-FolRα ADC STRO-002 induces immunogenic cell death (ICD) to enhance anti-tumor activity. Cancer Res 2022. [DOI: 10.1158/1538-7445.am2022-5591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
STRO-002 is an antibody-drug conjugate (ADC) composed of an anti-folate receptor alpha (FolRα) antibody conjugated to a tubulin-targeting hemiasterlin (SC209) warhead via a cleavable linker currently in clinical studies for ovarian and endometrial cancer. FolRα exhibits minimal expression in normal tissues but is overexpressed in several cancers such as ovarian, endometrial, and NSCLC. We previously showed that STRO-002 induces in vitro hallmarks of immunogenic cell death (ICD), such as increased calreticulin exposure and HMGB1 and ATP release in a FolRα dependent manner. Follow-up vaccination studies with murine MC38 tumor cells engineered to express human FolRα (MC38-hFolRa) were performed to further explore the significance of STRO-002-induced ICD and protective immunity in vivo. A single vaccination with STRO-002 or SC209 in vitro-treated MC38-hFolRa cells in immunocompetent mice resulted in 60% of animals rejecting a subsequent rechallenge with living MC38-hFolRa cells, while relapse was observed in most control mice. Including an additional booster vaccination further increased the proportion ( 90%) of animals remaining tumor free after rechallenge. These results demonstrate that tumor cells pre-treated with STRO-002 or SC209 undergo potent immunogenic cell damage which can, in turn, mount protective immunity in vivo.
The ability of STRO-002 to induce ICD that elicits an effective and robust anti-tumor immune response may translate into several advantages in the clinic. Induction of ICD is likely to offer a complementary anti-tumor mechanism in combination therapy regimens such as with check point inhibitors or VEGF blockade. We have demonstrated that STRO-002 in combination with avelumab in MC38-hFolRα-bearing mice significantly enhanced efficacy and durable anti-tumor immunity. More recent rechallenge studies reveal that this combination treatment suppresses growth of not only MC38-hFolRα but also MC38 wild-type tumor cells, indicating formation of immunological memory with signs of epitope spreading. Additionally, co-administration of STRO-002 with anti-VEGF therapy demonstrates improved TGI compared to monotherapy (p < 0.0001) in human ovarian OV-90 tumors.
The potent cytotoxic and immunostimulatory properties of STRO-002 may also contribute to enhancing efficacy in indications with low FolRα expression. Such tumor types include endometrial and NSCLC, in which STRO-002 has displayed potent monotherapy activity in preclinical studies. In a panel of endometrial PDX models, STRO-002 was significantly efficacious in 9/17 (53%) FolRα-positive tumors, including models with moderate and weak FolRα levels. In a NSCLC PDX model, a single dose of STRO-002 induced tumor regression and suppressed tumor growth for up to three months post-dose. In conclusion, the induction of ICD by STRO-002 has potential to increase anti-tumor activity in cancers with low FolRα expression.
Citation Format: Cristina L. Abrahams, Andrew McGeehan, Jennifer Smith, Robert Yuan, Kshama A. Doshi, Sihong Zhou, Xiaofan Li, Cuong Tran, Gang Yin, Arturo Molina, Kristin Bedard, Trevor Hallam. Anti-FolRα ADC STRO-002 induces immunogenic cell death (ICD) to enhance anti-tumor activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5591.
Collapse
|
5
|
Duran‐Villalobos CA, Ogonah O, Melinek B, Bracewell DG, Hallam T, Lennox B. Multivariate statistical data analysis of cell‐free protein synthesis toward monitoring and control. AIChE J 2021. [DOI: 10.1002/aic.17257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
6
|
Embry M, Zhou S, Cheng C, Yu J, Abrahams CL, Li X, Hanson J, Tran C, Yin G, Ahmad S, Bajjuri K, DeAlmeida V, Lupher M, Hallam T. Abstract 2250: STRO-002, an anti-FolR αADC, demonstrates immune-modulating properties and potentiates PD-L1 blockade. Cancer Res 2020. [DOI: 10.1158/1538-7445.am2020-2250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
There is growing evidence that tumor-targeted cytotoxins can also enhance anti-tumor immunity by inducing immunogenic cell death (ICD) in tumor cells and promoting recruitment of immune effector cells. We sought to investigate the immune stimulating potential of STRO-002, an antibody drug conjugate (ADC) composed of an anti-Folate receptor alpha (FolRα) antibody conjugated to a tubulin-targeting hemiasterlin warhead via a cleavable linker. FolRα is a single chain glycosylphosphatidylinositol-anchored membrane receptor glycoprotein with minimal expression in normal tissues. Its overexpression in several cancer indications has been described, including in ovarian, endometrial, non-small cell lung carcinoma (NSCLC), and triple negative breast cancer (TNBC), thus making it an ideal ADC target. We have previously demonstrated potent in vitro and in vivo activity of STRO-002 in several FolRα expressing models. Here we show that the hemiasterlin warhead, SC209, and STRO-002 ADC induced ICD in vitro as evidenced by presentation of cell-surface calreticulin and release of HMGB1 and ATP. As a result of ICD, STRO-002 treated FolRα positive cancer cells induced antigen-dependent monocyte activation, as well as, increased phagocytic activity in PBMCs co-cultured with tumor cells. To determine if these immunogenic properties could improve therapeutic efficacy, we evaluated STRO-002 in combination with the immune checkpoint inhibitor Avelumab (anti-PD-L1) in a mouse syngeneic MC38 model engineered to express human FolRα (MC38-hFolRα). Results showed that STRO-002 and Avelumab alone inhibited tumor growth and could induce complete responses (e.g. no palpable tumors) at low frequency (< 15%), while co-administration of STRO-002 and Avelumab significantly enhanced efficacy leading to complete response in the majority of animals. Furthermore, when animals that initially achieved complete response were re-challenged with MC38-hFolRα cells, they showed durable anti-tumor immunity, indicating formation of immunological memory. Immunohistochemical analysis conducted seven days after treatment revealed a significant increase in tumor-infiltrating cytotoxic CD8+ T cells in animals treated with combination of STRO-002 + Avelumab versus either monotherapy. Cumulatively, these results suggest that STRO-002 synergizes with Avelumab to enhance anti-tumor response by inducing ICD in tumor cells, which in turn, promote T cell recruitment. These data support the rationale for combining STRO-002 with immune checkpoint inhibitors to potentially enhance their clinical efficacy.
Citation Format: Millicent Embry, Sihong Zhou, Christine Cheng, Janice Yu, Cristina L. Abrahams, Xioafan Li, Jeff Hanson, Cuong Tran, Gang Yin, Shamim Ahmad, Krishna Bajjuri, Venita DeAlmeida, Mark Lupher, Trevor Hallam. STRO-002, an anti-FolRαADC, demonstrates immune-modulating properties and potentiates PD-L1 blockade [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2250.
Collapse
|
7
|
Abrahams C, Krimm S, Li X, Zhou S, Hanson J, Masikat MR, Bajjuri K, Heibeck T, Kothari D, Yu A, Henningsen R, Tran C, Yin G, Zawada J, Hang J, Bruhns M, Solis W, Steiner A, Galan A, Kline T, Stafford R, Yam A, Almeida VID, Lupher M, Hallam T. Abstract NT-090: PRECLINICAL ACTIVITY AND SAFETY OF STRO-002, A NOVEL ADC TARGETING FOLATE RECEPTOR ALPHA FOR OVARIAN AND ENDOMETRIAL CANCER. Clin Cancer Res 2019. [DOI: 10.1158/1557-3265.ovcasymp18-nt-090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
OBJECTIVES: Folate receptor alpha (FolRα) is a cell-surface glycoprotein, highly expressed in ovarian and endometrial adenocarcinoma, and thus a promising target for cancer therapy using antibody drug conjugates (ADCs). Most ADCs currently in development are generated by random attachment of the cytotoxic payload to the antibody and result in a heterogeneous mixture, comprised of many different forms that are likely to vary in stability and activity, and therefore may be suboptimal therapeutic agents. We have employed an E. coli cell-free expression system (XpressCFTM) and site-specific conjugation technology, to generate STRO-002, a novel homogenous FolRα-targeting ADC. STRO-002 was optimized by selection of the antibody, drug-linker, conjugation site and drug-antibody ratio (DAR) that conferred the best pharmacological properties. We have conducted preclinical studies to evaluate the stability of STRO-002 and characterize the pharmacological properties of the cytotoxic metabolite SC209. In vitro cytotoxicity assays and in vivo efficacy studies were conducted to evaluate the activity of STRO-002 in multiple ovarian cancer cell lines and xenografts. IND enabling toxicology studies were conducted to determine the safety profiles for STRO-002 and its metabolite SC209 in cynomolgous monkeys and rats, respectively.
RESULTS: Based on optimization studies, the anti-FolRα human IgG1 antibody (H01/SP8166) conjugated to a proprietary cleavable drug-linker (SC239) was selected for the lead ADC STRO-002. SC239 contains a tubulin-targeting 3-aminophenyl hemiasterlin warhead, SC209, which has potent cytotoxic activity. Based on most favorable anti-tumor activity, positions 180 and 404 on each heavy chain were selected for conjugation of SC239 to SP8166 to yield an ADC with DAR of ~ 4.
The drug-linkage in STRO-002 is highly stable and the released warhead, SC209, is a very weak substrate for cellular drug-resistance efflux pumps and is cleared rapidly from plasma. STRO-002 has potent but highly specific cytotoxic activity (0.1-3 nM) on multiple FolRα-positive ovarian cancer cell lines in vitro and anti-tumor efficacy in ovarian xenograft models. STRO-002 exhibits dose-dependent tumor growth inhibition in Igrov-1 tumor xenografts at a single dose and complete regression is achieved in Igrov-1 and OVCAR-3 tumors with a single dose at 10 and 5 mg/kg, respectively. In addition, administration of STRO-002 in combination with carboplatin confers added benefit in efficacy in Igrov-1 tumors. Toxicology studies show favorable safety profiles for STRO-002 and SC209. The main toxicity finding in monkeys dosed up to 9 mg/kg consists of reversible hematopoietic/lymphoid tissue toxicity, which is considered antigen-independent and is consistent with the anti-proliferative effects of SC209 observed in single-dose toxicology studies in rats. No evidence of ocular toxicity due to SC209 were observed in either species.
CONCLUSIONS: STRO-002 is a highly specific FolRα targeting ADC with minimal drug moiety release in circulation and the potential for an improved safety and activity profile, and a reduced risk of tumor drug resistance. Our data supports the advancement of STRO-002 to the clinic as a potential treatment of FolRα expressing malignancies such as ovarian cancer.
Citation Format: Cristina Abrahams, Stellanie Krimm, Xiaofan Li, Sihong Zhou, Jeffrey Hanson, Mary Rose Masikat, Krishna Bajjuri, Tyler Heibeck, Dharti Kothari, Abigail Yu, Robert Henningsen, Cuong Tran, Gang Yin, James Zawada, Julie Hang, Maureen Bruhns, Willy Solis, Alexander Steiner, Adam Galan, Toni Kline, Ryan Stafford, Alice Yam, Venita I. De Almeida, Mark Lupher, Jr., Trevor Hallam. PRECLINICAL ACTIVITY AND SAFETY OF STRO-002, A NOVEL ADC TARGETING FOLATE RECEPTOR ALPHA FOR OVARIAN AND ENDOMETRIAL CANCER [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-090.
Collapse
|
8
|
Solis W, Almeida VD, Abrahams C, Li X, Heibeck T, Bruhns M, Galan A, Hoffman H, Kiss R, Hallam T, Lupher M. Abstract 3897: Stability and safety evaluation of STRO-002, a site-specific anti-folate receptor alpha antibody-drug conjugate for the potential treatment of ovarian and endometrial cancers. Cancer Res 2019. [DOI: 10.1158/1538-7445.am2019-3897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Antibody-drug conjugates (ADCs) constitute an expanding class of therapeutic molecules in preclinical and clinical development for multiple oncology indications. Folate receptor alpha (FolRα) is a glycosylphosphatidylinositol-linked cell-surface glycoprotein that is overexpressed in ovarian, endometrial, lung, and triple negative breast cancers. In contrast, FolRα is minimally expressed on normal tissues, thus, making it an amenable ADC target. STRO-002, a site-specific ADC, is comprised of 3-aminophenyl hemiasterlin cytotoxic drug (SC209) conjugated to an aglycosylated anti-FolRα IgG1 antibody through a protease-cleavable linker at two engineered non-natural amino acids in each heavy chain (DAR ~4).
In vitro and in vivo stability studies, showed that STRO-002 is highly stable in circulation, with the warhead SC209 predominantly accumulating in tumor tissue. Toxicology and toxicokinetic studies were conducted to determine the safety profiles for STRO-002 and its metabolite SC209 in cynomolgous monkeys and rats, respectively. In single-dose toxicology studies in rats, SC209 was tolerated up to 0.6 mg/kg with the main toxicity findings predominantly found in hematopoietic/lymphoid tissue, consistent with tubulin targeting chemotherapeutic drugs. In a tissue cross-reactivity study with normal human tissues, STRO-002-specific membranous staining was detected in Fallopian tubes, kidney (tubules), and placenta (trophoblasts). In a definitive safety study in cynomolgus monkeys, pharmacologically relevant model for toxicity testing, STRO-002 was tolerated at up to 9 mg/kg when intravenously administered on days 1 and 22 followed by a 4-week observation period. The most prominent STRO-002-related antigen-independent toxicity finding was dose-related, minimal to marked, and cyclical neutropenia. There were no antigen-dependent toxicity findings and no evidence of ocular toxicity. Toxicokinetic analysis confirmed dose proportional STRO-002 exposures (total antibody, ADC, and SC209 catabolite) at all doses tested. In summary, STRO-002 ADC has a favorable nonclinical safety and pharmacokinetic profiles and a Phase I study of STRO-002 in patients with ovarian and endometrial cancer has been initiated.
Citation Format: Willy Solis, Venita De Almeida, Cristina Abrahams, Xiaofan Li, Tyler Heibeck, Maureen Bruhns, Adam Galan, Heidi Hoffman, Robert Kiss, Trevor Hallam, Mark Lupher. Stability and safety evaluation of STRO-002, a site-specific anti-folate receptor alpha antibody-drug conjugate for the potential treatment of ovarian and endometrial cancers [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 3897.
Collapse
|
9
|
Abrahams CL, Li X, Embry M, Yu A, Krimm S, Krueger S, Greenland NY, Wen KW, Jones C, DeAlmeida V, Solis WA, Matheny S, Kline T, Yam AY, Stafford R, Wiita AP, Hallam T, Lupher M, Molina A. Targeting CD74 in multiple myeloma with the novel, site-specific antibody-drug conjugate STRO-001. Oncotarget 2018; 9:37700-37714. [PMID: 30701025 PMCID: PMC6340874 DOI: 10.18632/oncotarget.26491] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 12/04/2018] [Indexed: 01/22/2023] Open
Abstract
STRO-001 is a site-specific, predominantly single-species, fully human, aglycosylated anti-CD74 antibody-drug conjugate incorporating a non-cleavable linker-maytansinoid warhead with a drug-antibody ratio of 2 which was produced by a novel cell-free antibody synthesis platform. We examined the potential pharmacodynamics and anti-tumor effects of STRO-001 in multiple myeloma (MM). CD74 expression was assessed in MM cell lines and primary bone marrow (BM) MM biopsies. CD74 mRNA was detectable in CD138+ enriched plasma cells from 100% (892/892) of patients with newly diagnosed MM. Immunohistochemistry confirmed CD74 expression in 35/36 BM biopsies from patients with newly diagnosed and relapsed/refractory MM. Cytotoxicity assays demonstrated nanomolar STRO-001 potency in 4/6 MM cell lines. In ARP-1 and MM.1S tumor-bearing mice, repeat STRO-001 dosing provided significant antitumor activity with eradication of malignant hCD138+ BM plasma cells and prolonged survival. In a luciferase-expressing MM.1S xenograft model, dose-dependent STRO-001 efficacy was confirmed using bioluminescent imaging and BM tumor burden quantification. Consistent with the intended pharmacodynamic effect, STRO-001 induced dose-responsive, reversible B-cell and monocyte depletion in cynomolgus monkeys, up to a maximum tolerated 10 mg/kg, with no evidence of off-target toxicity. Collectively, these data suggest that STRO-001 is a promising therapeutic agent for the treatment of MM.
Collapse
|
10
|
Song S, Everist R, Deans R, Nesbitt-Hawes E, Hallam T, Abbott J. Using Physical Therapy as an Adjunct for Women with Chronic Pelvic Pain and Pelvic Floor Myalgia. J Minim Invasive Gynecol 2018. [DOI: 10.1016/j.jmig.2018.09.631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
11
|
Solis W, Almeida VD, Yu A, Bruhns M, Zawada J, Galan A, Matheny S, Molina A, Hallam T, Lupher M. Abstract 742: Nonclinical safety evaluation of STRO-001, a site-specific anti-CD74 antibody-drug conjugate for the potential treatment of B-cell malignancies. Cancer Res 2018. [DOI: 10.1158/1538-7445.am2018-742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Antibody-drug conjugates (ADCs) constitute an expanding class of therapeutic molecules in preclinical and clinical development for multiple oncology indications. These antibody-based therapeutics are designed to selectively deliver cytotoxic payloads to tumor targets to improve efficacy and minimize toxicity. Cluster of differentiation 74 (CD74), a membrane-bound glycoprotein, is an antigen amenable ADC targeting because of its low expression in normal tissues and over expression in B-cell malignancies (multiple myeloma and non-Hodgkin's Lymphoma). STRO-001, a well-defined, homogenous, and site-specific ADC, is comprised of maytansinoid cytotoxic drugs conjugated to an anti-CD74 aglycosylated antibody (SP7219) through a noncleavable linker at two engineered non-natural amino acids. In an in vitro immunological activation assay, STRO-001 did not elicit cytokine production when incubated with human PBMCs for 48 hours, suggesting a low risk for immunological response in cancer patients. In a tissue cross-reactivity study with human tissues, STRO-001-specific membranous staining was detected primarily in lymphoid organs and lymphocytic infiltrates in multiple non-lymphoid tissues. In an exploratory nonclinical safety study in cynomolgus monkeys, a pharmacologically relevant model for toxicity testing, STRO-001 was tolerated at 1, 3, and 10 mg/kg, but not at 30 mg/kg, when intravenously administered on days 1 and 15 followed by a 4-week observation period. Dose-dependent and transient decreases in B-cells and monocytes were observed at tolerated doses (on-target pharmacology), with no effects on NK/T-cells. At tolerated doses, the main findings included reversible toxicities to hematopoietic and lymphoid tissues that correlated with cytopenias. Hematopoietic toxicity is considered antigen-independent, clinically manageable, and consistent with that of other ADCs with similar payloads. Toxicokinetic analysis confirmed drug exposures (total antibody, ADC, and a prominent linker-maytansine catabolite) with evidence of non-linearity suggesting target-dependent clearance. In summary, STRO-001 ADC has a favorable nonclinical safety profile and Phase I study of STRO-001 in patients with B-cell malignancies is planned.
Citation Format: Willy Solis, Venita De Almeida, Abigail Yu, Maureen Bruhns, James Zawada, Adam Galan, Shannon Matheny, Arturo Molina, Trevor Hallam, Mark Lupher. Nonclinical safety evaluation of STRO-001, a site-specific anti-CD74 antibody-drug conjugate for the potential treatment of B-cell malignancies [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 742.
Collapse
|
12
|
Li X, Abrahams C, Zhou S, Krimm S, Henningsen R, Stephenson H, Hanson J, Masikat MR, Bajjuri K, Heibeck T, Tran C, Yin G, Zawada J, Sarma G, Chen J, Bruhns M, Solis W, Steiner A, Galan A, Kline T, Stafford R, Yam A, Almeida VID, Lupher M, Hallam T. Abstract 1782: Discovery and activity of STRO-002, a novel ADC targeting folate receptor alpha for ovarian and endometrial cancer. Immunology 2018. [DOI: 10.1158/1538-7445.am2018-1782] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
13
|
Abrahams C, Li X, DeAlmeida V, Embry M, Yu A, Krim S, Hoffmann H, Zawada J, Bruhns M, Matheny S, Bussell S, Kline T, Yam A, Stafford R, Hallam T, Lupher M, Molina A. Abstract 67: Characterization and preclinical development of STRO-001, a novel CD74-targeting antibody-drug conjugate (ADC) for the treatment of B-cell malignancies. Cancer Res 2017. [DOI: 10.1158/1538-7445.am2017-67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
CD74 is a type II transmembrane glycoprotein involved in the formation and transport of MHC class II protein. CD74 is highly expressed in many B-cell malignancies with limited expression in normal tissues (Stein R. et al., CCR 2007). STRO-001 is a novel CD74-targeting ADC containing an anti-CD74 aglycosylated human IgG1 antibody (SP7219) conjugated to a non-cleavable dibenzocyclooctyne (DBCO)-maytansinoid linker-warhead. SP7219 was discovered from a Fab ribosome display library based on Sutro’s Xpress CFTM technology. Highly efficient site-specific conjugation enabled by our cell-free antibody production and click chemistry results in a well-defined homogeneous ADC drug product with a drug-antibody ratio (DAR) of 2. Conjugation sites were selected based on highest stability both in vitro and in vivo, thereby limiting loss of drug moiety from STRO-001 in circulation. Due to its limited cell permeability, the major catabolite released by STRO-001 has 1000X lower cell killing activity on CD74 positive and negative cells compared to the reference cytotoxic maytansine. In vitro cytotoxicity assays show potent activity of STRO-001 in a diverse panel of B-cell tumor lines including 4 multiple myeloma (MM), 9 germinal center B-cell (GCB) diffuse large B-cell lymphoma (DLBCL), 3 activated B-cell (ABC) DLBCL, and 3 mantle cell lymphoma (MCL) cell lines with IC50 ranging from 0.17-20 nM. CD74 cell surface expression is required for STRO-001 cytotoxic activity but expression level, as measured by antibody-binding capacity, does not correlate with in vitro potency (R2=0.4640). STRO-001 inhibits the formation of visceral tumors (p<0.004) and prevents growth of CD138+ plasma cells in bone marrow (BM) after 4 weekly doses of 3 mg/kg in the ARP-1 disseminated MM xenograft model. STRO-001 dosed at 3 mg/kg weekly x 3 also eradicates malignant BM plasma cells (p<0.0001) and prolongs survival in the MM.1S disseminated model (100% animals alive at >90 days). STRO-001 exhibits dose-dependent tumor growth inhibition in SU-DHL-6 xenografts starting at 2.5 mg/kg weekly x 3 doses. The combination of bendamustine/rituximab (BR) + STRO-001 further improves tumor suppression in SU-DHL-6 xenografts compared to vehicle (p = 0.002) or BR alone (p = 0.02). Preliminary studies with a MCL xenograft model, Jeko-1, demonstrate potent anti-tumor activity compared to vehicle (p<0.0001) starting at a single STRO-001 dose of 3 mg/kg, with ongoing tumor stasis up to 21 days after treatment. STRO-001 reduces normal B-cells in cynomologous monkeys, providing pharmacodynamic evidence of B-cell targeting. Based on these encouraging observations, STRO-001 is advancing to IND-enabling studies for the treatment of CD74-expressing B-cell malignancies.
Citation Format: Cristina Abrahams, Xiaofan Li, Venita DeAlmeida, Millicent Embry, Abigail Yu, Stellanie Krim, Heidi Hoffmann, James Zawada, Maureen Bruhns, Shannon Matheny, Stuart Bussell, Toni Kline, Alice Yam, Ryan Stafford, Trevor Hallam, Mark Lupher, Arturo Molina. Characterization and preclinical development of STRO-001, a novel CD74-targeting antibody-drug conjugate (ADC) for the treatment of B-cell malignancies [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 67. doi:10.1158/1538-7445.AM2017-67
Collapse
|
14
|
Molina A, Yu A, Abrahams C, Embry M, Li X, DeAlmeida V, Lee J, Matheny S, Kline T, Yam A, Stafford R, Hallam T, Lupher M. STRO-001, A NOVEL ANTI-CD74 ANTIBODY DRUG CONJUGATE (ADC) FOR TREATMENT OF B-CELL NON-HODGKIN'S LYMPHOMAS (NHL). Hematol Oncol 2017. [DOI: 10.1002/hon.2438_121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
15
|
Hallam T, Duffy CM, Minakata T, Ando M, Sirringhaus H. A scanning Kelvin probe study of charge trapping in zone-cast pentacene thin film transistors. NANOTECHNOLOGY 2009; 20:025203. [PMID: 19417265 DOI: 10.1088/0957-4484/20/2/025203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We have used scanning Kelvin probe microscopy (SKPM) as a local probe to study charge trapping in zone-cast pentacene field effect transistors on both SiO(2) and benzocyclobutene (BCB) substrates. Annealing at 130 degrees C was found to reduce the threshold voltage, susceptibility to negative gate bias stress and trapping of positive charges within single pentacene grains. We conclude that oxygen is able to penetrate and disassociatively incorporate into crystalline pentacene, chemically creating electrically active defect states. Screening of a positive gate bias caused by electron injection from Au into pentacene was directly observed with SKPM. The rate of screening was found to change significantly after annealing of the film and depended on the choice of gate dielectric.
Collapse
|
16
|
Simmons M, Ruess F, Goh K, Hallam T, Schofield S, Oberbeck L, Curson N, Hamilton A, Butcher M, Clark R, Reusch T. Scanning probe microscopy for silicon device fabrication. MOLECULAR SIMULATION 2005. [DOI: 10.1080/08927020500035580] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
17
|
Schofield SR, Curson NJ, Simmons MY, Ruess FJ, Hallam T, Oberbeck L, Clark RG. Atomically precise placement of single dopants in si. PHYSICAL REVIEW LETTERS 2003; 91:136104. [PMID: 14525322 DOI: 10.1103/physrevlett.91.136104] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2003] [Indexed: 05/24/2023]
Abstract
We demonstrate the controlled incorporation of P dopant atoms in Si(001), presenting a new path toward the creation of atomic-scale electronic devices. We present a detailed study of the interaction of PH3 with Si(001) and show that it is possible to thermally incorporate P atoms into Si(001) below the H-desorption temperature. Control over the precise spatial location at which P atoms are incorporated was achieved using STM H lithography. We demonstrate the positioning of single P atoms in Si with approximately 1 nm accuracy and the creation of nanometer wide lines of incorporated P atoms.
Collapse
|
18
|
Clark RG, Brenner R, Buehler TM, Chan V, Curson NJ, Dzurak AS, Gauja E, Goan HS, Greentree AD, Hallam T, Hamilton AR, Hollenberg LCL, Jamieson DN, McCallum JC, Milburn GJ, O'Brien JL, Oberbeck L, Pakes CI, Prawer SD, Reilly DJ, Ruess FJ, Schofield SR, Simmons MY, Stanley FE, Starrett RP, Wellard C, Yang C. Progress in silicon-based quantum computing. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2003; 361:1451-1471. [PMID: 12869321 DOI: 10.1098/rsta.2003.1221] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We review progress at the Australian Centre for Quantum Computer Technology towards the fabrication and demonstration of spin qubits and charge qubits based on phosphorus donor atoms embedded in intrinsic silicon. Fabrication is being pursued via two complementary pathways: a 'top-down' approach for near-term production of few-qubit demonstration devices and a 'bottom-up' approach for large-scale qubit arrays with sub-nanometre precision. The 'top-down' approach employs a low-energy (keV) ion beam to implant the phosphorus atoms. Single-atom control during implantation is achieved by monitoring on-chip detector electrodes, integrated within the device structure. In contrast, the 'bottom-up' approach uses scanning tunnelling microscope lithography and epitaxial silicon overgrowth to construct devices at an atomic scale. In both cases, surface electrodes control the qubit using voltage pulses, and dual single-electron transistors operating near the quantum limit provide fast read-out with spurious-signal rejection.
Collapse
|
19
|
Schimmel SD, Hallam T. Rapid alteration in Ca++ content and fluxes in phorbol 12-myristate 13-acetate treated myoblasts. Biochem Biophys Res Commun 1980; 92:624-30. [PMID: 7356487 DOI: 10.1016/0006-291x(80)90379-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|