AMG 757, a Half-Life Extended, DLL3-Targeted Bispecific T-Cell Engager, Shows High Potency and Sensitivity in Preclinical Models of Small Cell Lung Cancer

Author Manuscript Published OnlineFirst on November 17, 2020; DOI: 10.1158/1078-0432.CCR-20-2845 Author manuscripts have been peer reviewed and accepted for publication but have not yet been edited.

Research Article

Michael J. Giffin,1* Keegan Cooke,1* Edward K. Lobenhofer,2 Juan Estrada,1 Jinghui Zhan,1 Petra Deegen,3 Melissa Thomas,4 Christopher M. Murawsky,5 Jonathan Werner,2 Siyuan Liu,1 Fei Lee,6 Oliver Homann,7 Matthias Friedrich,3 Joshua T. Pearson,8 Tobias Raum,9 Yajing Yang,1 Sean Caenepeel,1 Jennitte Stevens,10 Pedro J. Beltran,1 Jude Canon,1 Angela Coxon,1 Julie M. Bailis,6 Paul E. Hughes1

1Oncology Research, Amgen Research, Thousand Oaks, CA, USA; 2Translational Safety & Bioanalytical Sciences, Amgen Research, Thousand Oaks, CA, USA; 3Translational Safety & Bioanalytical Sciences, Amgen Research (Munich) GmbH, Munich, Germany; 4Therapeutic Discovery, Amgen Research, South San Francisco, CA; 5Therapeutic Discovery, Amgen Research, Burnaby, BC, Canada; 6Oncology Research, Amgen Research, South San Francisco, CA, USA; 7Genome Analysis Unit, Amgen Research, South San Francisco, CA, USA; 8Pharmacokinetics & Drug Metabolism, Amgen Research, South San Francisco, CA, USA; 9Therapeutic Discovery, Amgen Research (Munich) GmbH, Munich, Germany; 10Therapeutic Discovery, Amgen Research, Thousand Oaks, CA, USA

*Contributed equally to this work.

Current address for Michael J. Giffin is Process Development, Amgen Inc., Thousand Oaks, CA, USA. Current address for Joshua T. Pearson is Pharmacodynamics, Pharmacokinetics, and Drug, Merck Research Labs, South San Francisco, CA, USA. Current address for Pedro J. Beltran is Discovery Biology, UNITY Biotechnology, South San Francisco, CA, USA

Correspondence: Paul E. Hughes, Amgen Research, One Amgen Center Drive, Thousand Oaks, CA, USA 91320-1799; Tel: 1-805-447-1137; Email: [email protected]; Julie M. Bailis, Amgen Research, 1120 Veterans Blvd, South San Francisco, CA, USA 94080; Tel: 1-650-244-2361; Email: [email protected]

Running title: AMG 757 in Preclinical Models of Small Cell Lung Cancer

Keywords: SCLC, AMG 757, BiTE®, orthotopic model, DLL3

Financial support: This work was supported by Amgen Inc.

Conflicts of interest: MJG, KC, EKL, JE, JZ, MT, CMM, JW, SL, FL, OH, JTP, YY, SC, JS, PJB, JC, AC, JMB, and PEH are or were employees of and own stock in Amgen Inc. PD, MF, and TR are employees of and own stock in Amgen Research (Munich) GmbH.

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Downloaded from clincancerres.aacrjournals.org on September 23, 2021. © 2020 American Association for Cancer Research. Author Manuscript Published OnlineFirst on November 17, 2020; DOI: 10.1158/1078-0432.CCR-20-2845 Author manuscripts have been peer reviewed and accepted for publication but have not yet been edited.

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1 Abstract

2 Purpose: Small cell lung cancer (SCLC) is an aggressive neuroendocrine tumor with a high

3 relapse rate, limited therapeutic options, and poor prognosis. We investigated the antitumor

4 activity of AMG 757, a half-life extended bispecific T-cell engager molecule targeting delta-like

5 ligand 3 (DLL3) — a target that is selectively expressed in SCLC tumors but with minimal

6 normal tissue expression.

7 Methods: AMG 757 efficacy was evaluated in SCLC cell lines and in orthotopic and patient-

8 derived xenograft (PDX) mouse SCLC models. Following AMG 757 administration, changes in

9 tumor volume, pharmacodynamic changes in tumor-infiltrating T cells (TILs), and the spatial

10 relationship between the appearance of TILs and tumor histology were examined. Tolerability

11 was assessed in nonhuman primates (NHP).

12 Results: AMG 757 showed potent and specific killing of even those SCLC cell lines with very

13 low DLL3 expression (< 1000 molecules per cell). AMG 757 effectively engaged systemically

14 administered human T cells, induced T cell activation, and redirected T cells to lyse tumor cells

15 to promote significant tumor regression and complete responses in PDX models of SCLC and in

16 orthotopic models of established primary lung SCLC and metastatic liver lesions. AMG 757 was

17 well tolerated with no AMG 757-related adverse findings up to the highest tested dose (4.5

18 mg/kg weekly) in NHP. AMG 757 exhibits an extended half-life in NHP which is projected to

19 enable intermittent administration in patients.

20 Conclusions: AMG 757 has a compelling safety and efficacy profile in preclinical studies

21 making it a viable option for targeting DLL3-expressing SCLC tumors in the clinical setting.

22 Abstract word count: 249/250

1 Translational Relevance

2 Small cell lung cancer (SCLC) is an aggressive neuroendocrine malignancy that is associated

3 with a high relapse rate and dismal prognosis. Recent immunotherapeutic approaches using

4 immune checkpoint inhibitors have only modestly improved clinical outcomes. AMG 757 is a

5 first-in-class, half-life-extended bispecific T-cell engager that redirects T cells to specifically kill

6 DLL3-expressing tumor cells. In biologically relevant orthotopic and patient-derived xenograft

7 SCLC disease models, AMG 757 promoted significant tumor regression and complete antitumor

8 responses against established tumors. The antitumor effect of AMG 757 is linked to its ability to

9 promote intratumoral infiltration of activated T cells and facilitate T-cell mediated killing of DLL3-

10 expressing SCLC tumors. This, together with its acceptable nonclinical safety profile, suggest

11 that AMG 757 may be a promising novel option for SCLC therapy. AMG 757 is currently under

12 evaluation in a phase 1 clinical study (NCT03319940) for patients with SCLC.

13 Word count: 142/150

1 Introduction

2 Small cell lung cancer (SCLC) is an aggressive neuroendocrine tumor prone to early

3 metastasis, accounting for 10%–15% of all lung cancers (1-3) and associated with poor 5-year

4 survival (4). Disease relapse and resistance to therapy are common following an initial response

5 to etoposide and platinum-based chemotherapy with or without radiation therapy (5). Immune

6 checkpoint blockade has increased overall survival (OS) in SCLC despite relatively modest

7 response rates (6-9). The anti-programmed cell death-1 (anti-PD-1) antibodies nivolumab and

8 pembrolizumab received accelerated approval in the United States for the treatment of

9 metastatic SCLC with progression on or after platinum-based chemotherapy and at least one

10 other line of therapy (10,11); however, subsequent studies did not confirm increased OS

11 (12,13). The promise of targeted therapies has also not yet been realized in SCLC; a DLL3-

12 targeted antibody drug conjugate with early evidence of clinical activity demonstrated no benefit

13 in a subsequent phase 3 trial (14). Therapeutic agents with different mechanisms of action are

14 still urgently needed for patients with SCLC.

15 Bispecific T-cell engager (BiTE®) molecules are a clinically validated therapeutic modality that

16 redirect a patient’s T cells to kill tumor cells (15). Blinatumomab, the first BiTE® molecule in

17 clinical development, is approved for the treatment of relapsed/refractory B-cell precursor acute

18 lymphoblastic leukemia (16-18) and also demonstrates efficacy in non-Hodgkin lymphoma (19-

19 21). The BiTE® molecule AMG 420, which targets BCMA, demonstrated a 70% response rate in

20 multiple myeloma with 50% minimal residual disease-negative complete responses at the

21 maximum tolerated dose in a phase 1 study (22). In solid tumors, therapeutic index has been a

22 major challenge for the successful development of T cell bispecific antibodies (23,24).

23 Development of AMG 110 (MT110), which targets EpCAM, was discontinued due to on-target,

24 dose-limiting toxicity in the liver and gastrointestinal tract (24). The clinical activity of the CEA-

1 targeting T cell bispecific antibody, cibisatamab, is also associated with dose-limiting on-target

2 toxicity in gastrointestinal tissues (23). These data highlight the need to identify therapeutic

3 targets with tumor-specific or tumor-selective expression profiles (23,24).

4 To identify potential BiTE® molecule targets in SCLC, we profiled predicted cell surface proteins

5 for differential expression in a panel of SCLC tumors versus an array of normal tissues and

6 identified the Notch ligand, delta-like ligand 3 (DLL3). DLL3 is expressed during embryonic

7 development (25-28), and together with achaete-scute complex homologue 1, a transcription

8 factor that regulates DLL3 expression, is required for neuroendocrine differentiation and SCLC

9 tumorigenesis (29-31). We generated BiTE® molecules targeting DLL3 to explore T cell-

10 redirected lysis against SCLC tumors. We initially evaluated an anti-DLL3 BiTE® molecule in the

11 original tandem single-chain variable fragment (scFv) format (32), which requires administration

12 via continuous intravenous (cIV) infusion due to its short half-life (33,34). We then developed

13 AMG 757, a half-life extended (HLE) BiTE® molecule, by fusing an immunoglobulin G (IgG)

14 crystallizable fragment (Fc) domain to the core BiTE® molecule structure, which enables longer

15 dosing intervals in patients.

16 Here, we describe the potent, specific activity of an anti-DLL3 BiTE® molecule and AMG 757

17 against SCLC cell lines in vitro, including high sensitivity for cells with low levels of DLL3

18 expression (< 1000 DLL3 molecules per cell). We demonstrate that once weekly administration

19 of AMG 757 drives T cell activation and expansion in established patient-derived xenograft

20 (PDX) and orthotopic SCLC tumors in mouse models, leading to significant tumor regression

21 including complete antitumor responses. We report that AMG 757 is well tolerated in nonhuman

22 primate (NHP) toxicology studies with no AMG 757-related adverse findings up to the highest

23 dose level tested (4.5 mg/kg administered weekly), and that AMG 757 exhibits an extended half-

24 life. The potency and sensitivity of AMG 757 in SCLC models, together with favorable

1 nonclinical safety and pharmacokinetic (PK) profiles, suggests that AMG 757 has potential as a

2 DLL3-targeted immune therapy for SCLC.

1 Methods

2 Cell lines

3 DMS 79, NCI-H2171, NCI-H889, SHP-77, NCI-H211, NCI-H460, HEK-293, and Chinese

4 hamster ovary cell lines were purchased from the American Type Culture Collection, NCI-H82

5 from the DSMZ-German Collection of Microorganisms and Cell Cultures, and COR-L279 from

6 Sigma-Aldrich. Cell lines were analyzed for authenticity using DNA-fingerprinting techniques

7 such as short tandem repeat profiling. All cell lines tested negative for mycoplasma

8 contamination. Research Resource Identifiers for cell lines are listed in Supplementary Tables

9 (Table S1).

10 Cell-based assays

11 DLL3 expression levels on cell lines were quantified in flow cytometry experiments using

12 standard receptor quantitation methods (QIFIKIT® assay (Dako) or Quantum Simply Cellular®

13 assay (Bangs Laboratories)) and analyzed using BD FACSDiva and GraphPad Prism or

14 QuickCals software (see Supplementary Methods)

15 Transfected HEK-293 cells were plated at 5,000 cells/well and treated with activated T cells at

16 50,000 cells/well (10:1 effector to target [E:T] cell ratio) and BiTE® molecules at 50 ng/mL final

17 concentration, titrated 4-fold across the plate (12-point titration curve) in duplicate. After

18 incubation for 20 hours, cell viability was measured with the Steady-Glo® Luciferase assay

19 (Promega).

20 Effector cells (2 × 105 human or NHP PBMC or isolated human CD3+ T cells) were co-cultured

21 with Vybrant™ (Thermo Fisher Scientific) DiO/Dil-labeled target cell lines at an E:T cell ratio of

22 2:1 or 5:1 and serial dilutions of AMG 757 in 96-well, flat-bottom plates. Cells were cultured for

23 48 hours at 37°C in a 5% CO2 humidified incubator and washed with FACS buffer. PBMC were

1 stained with a fluorochrome-labeled anti-CD14 antibody (BD Biosciences) to define

2 DiO+/CD14− target cells (30 min; 4°C), washed with FACS buffer, and resuspended in 100 μL

3 of FACS buffer containing 0.5 μg/mL propidium iodide. All flow cytometry experiments were

4 analyzed using FACSCanto II or LSRFortessa flow cytometers and the BD FACSDiva™

5 software (BD Biosciences) and data were fitted to a four-parameter nonlinear fit model

6 sigmoidal dose-response curve (GraphPad Prism). T-cell activation was evaluated by flow

7 cytometry after incubation as described for T cell-dependent cellular cytotoxicity (TDCC)

8 assays. T cells were washed and stained protected from light for 30 minutes at 4°C for CD4,

9 CD8, and the activation markers CD69, CD71, PD-1, and PD-L1 using directly conjugated

10 antibodies. For evaluation of granzyme B and perforin expression, cells stained for cell surface

11 CD4 and CD8 were fixed and permeabilized (Cytofix/Cytoperm, BD Biosciences) and then

12 stained with FITC-conjugated anti-granzyme B and allophycocyanin-conjugated anti-perforin

13 antibodies. Cells were analyzed by flow cytometry. Cytokine levels were analyzed from

14 supernatants of cytotoxicity assays using human and NHP Th1/Th2 cytometric bead arrays (BD

15 Biosciences) (see Supplementary Methods).

16 Mouse model studies

17 All research protocols were approved by the Amgen Institutional Animal Care and Use

18 Committee (IACUC) (Study number: 2009-00046).

19 For the admixture xenograft studies, mice were inoculated in the subcutaneous flank with a

20 mixture of 5 × 106 luciferase-labeled NCI-H82 or SHP-77 tumor cells and 1 × 106 human CD3+

21 T cells on study day 0. Mice were administered 0.5 mg/kg BiTE® molecule by intraperitoneal

22 injection daily from day 1 through day 11. Tumor measurements and body weights were

23 collected twice a week throughout the study.

1 For the PDX models, female NOD.Cg-Prkdcscid Il2rgtm1Sug/JicTac (NOG) mice (Taconic)

2 were implanted subcutaneously with patient-derived SCLC tumor fragments (LXFS 1129 and

3 LXFS 538; Charles River Laboratories). After an induction period of 41 and 29 days

4 respectively, when the average tumor volume was 94–123 mm3, mice were randomized into two

5 groups and administered activated human CD3+ T cells (2 × 107) by intravenous infusion on

6 study day 0. Human CD3+ T cells, isolated from PBMC from two different donors using negative

7 selection, were purchased from AllCells (Alameda, CA) and activated in vitro using IL-2 and

8 CD3/CD28/CD2 (STEMCELL Technologies). T cell expansion was monitored by cell count, and

9 T cell activation was assessed by measuring CD25 expression by flow cytometry. The PDX

10 models used T cells from two different donors, one of which was used in the admixture

11 xenograft studies. For the PDX efficacy models, mice (n = 9‒10/group) were administered 3

12 mg/kg BiTE® molecules by intraperitoneal injection on days 1, 8, and 15. Tumor volumes and

13 body weights were measured twice a week until study end at day 23. For pharmacodynamic

14 analysis, mice were administered a single dose of 3 mg/kg BiTE® molecules on day 1 by

15 intraperitoneal injection. At 96 hours post dose, tumors were collected and dissociated for

16 analysis of tumor-infiltrating T cells. Additional details are provided in the Supplementary

17 Methods.

18 Female NOD-scid IL2Rgammanull (NSG) mice (The Jackson Laboratory), 6‒7 weeks of age,

19 were inoculated intravenously by tail vein injection with 1 × 106 SHP-77 Luc cells or 5 × 104

20 NCI-H82 Luc cells on day 0. On day 7, mice were imaged ventrally and randomized into

21 treatment groups (n = 10/group) using the deterministic method (Studylog Systems, Inc). Each

22 mouse was injected intravenously with 2 × 107 CD3+ human T cells on study day 7, prepared as

23 described above. BiTE® molecules were dosed intraperitoneally once a week for a total of two

24 doses (study days 8 and 15). Bioluminescence imaging (BLI) quantifications of the ventral lung

25 area and body weights were collected twice a week throughout the study. In the NCI-H82 Luc

1 model, livers were excised on day 22 and visible metastases were enumerated using a

2 dissecting microscope.

3 For pharmacodynamic analysis of SHP-77 orthotopic tumors, mice were inoculated with SHP-77

4 cells as described above and then injected intravenously with 2 × 107 CD3+ human T cells on

5 study day 32. On study day 36, the mice were imaged ventrally and randomized to treatment

6 groups (n = 4/group) and then treated with a single dose of 3 mg/kg BiTE® molecule by

7 intraperitoneal injection. Tumor dissociation and analysis are described in Supplemental

8 Methods.

9 NHP in vivo pharmacokinetics

10 All research protocols were approved by the IACUC (NHP toxicology study number: 121424,

11 NHP PK study number: 121985). PK analysis is described in the Supplementary Methods.

12 A complete list of reagents and their catalog numbers are listed in Supplementary Tables

13 (Table S2).

1 Results

2 DLL3 is an optimal BiTE® molecule target

3 We used RNA sequencing (RNA-Seq) to profile 28 SCLC primary and metastatic tumor

4 samples, and approximately 250 normal tissue samples representing an extensive panel of

5 tissues, to identify potential targets with differential tumor expression using gene-ranking

6 heuristics that prioritized target prevalence in tumors and minimal expression in essential

7 normal tissues. Genes in the preliminary list were then further evaluated based on literature,

8 predicted extracellular domain structure, and feasibility of antibody generation. The Notch ligand

9 DLL3, a type I membrane protein expressed primarily during development (31), was prioritized

10 for further evaluation. We continued to obtain and analyze comparative data on the DLL3

11 expression profile as additional normal tissue samples and updated gene models became

12 available. The final analysis showed that DLL3 RNA was detected at fragments per kilobase of

13 transcript per million mapped reads (FPKM) ≥1 in 82% of primary and metastatic SCLC tumors

14 (maximum FPKM, 116; median, 11.5), and expressed at low levels in brain, spinal cord, pituitary

15 gland, and testis (FPKM, 1.06–6.55) (Fig. S1A).

16 Saunders and colleagues first reported identification of DLL3 as a therapeutic target based on

17 prevalent mRNA expression in SCLC and large cell neuroendocrine tumors and limited

18 expression in normal brain, pancreatic, and esophageal tissues (29). Given prior clinical

19 experience with solid tumor BiTE® molecule targets, our parallel studies had focused on

20 obtaining a detailed understanding of DLL3 protein expression in normal tissues (Table S3).

21 Immunohistochemistry analysis confirmed DLL3 expression in neurons in the human brain

22 (cerebrum, cerebellum, hypothalamus, and hippocampus), secretory cells of the human and

23 NHP anterior pituitary and the NHP pars intermedia, and human and NHP pancreatic islets,

24 consistent with the mRNA profile. DLL3 staining in these normal tissues was of weak (1+) to

1 mild (2+) intensity and predominantly cytoplasmic (Fig. S2). The low, mainly cytoplasmic

2 localization of DLL3 on normal tissues is not expected to be accessible to BiTE® molecule

3 activity.

4 In SCLC tumors, 30 of 35 (86%) of samples revealed DLL3 expression by immunostaining (Fig.

5 S1B), consistent with the RNA-Seq data (Fig. S1A). The DLL3 staining pattern was

6 homogeneous in both membrane and cytoplasm. Among the DLL3-positive tumors, staining

7 intensity was weak (1+) in 10 (28%), mild (2+) in 14 (40%), and intense (3+) in 6 (17%) tumors,

8 with > 90% of neoplastic cells staining positive for DLL3 in most samples. The intensity of

9 immunostaining did not correlate with tumor stage, grade, or other clinical factors. DLL3 mRNA

10 and protein were also detected in other solid tumor types, including melanoma and glioblastoma

11 (Fig. S3). The prevalent membrane-associated staining of DLL3 in SCLC tumors, together with

12 its low, mainly cytoplasmic expression in a few normal tissues, supported the advancement of

13 DLL3 as a target for a BiTE® molecule.

14 In SCLC cell lines, RNA-Seq analysis showed a range of DLL3 expression levels (Fig. S1A).

15 Flow cytometry analysis of DLL3 cell surface expression showed generally low levels of DLL3,

16 ranging from approximately 800 DLL3 molecules/cell (NCI-H211) to an estimated 3,222 DLL3

17 molecules/cell (SHP-77) based on quantitative flow cytometry analysis (Table S4). These data

18 were concordant with the DLL3 immunohistochemistry data (Fig. S1C), with intense staining

19 (3+) of the SHP-77 cell line and weak staining (1+) of the NCI-H211 cell line. DLL3 mRNA and

20 protein were not detected in the NSCLC cell line NCI-H460, a tumor type where DLL3

21 expression has not been reported. Collectively, these studies established that DLL3 expression

22 in SCLC cell lines and tumors are similar.

1 Anti-DLL3 BiTE® molecule binding and activity in vitro

2 We generated an anti-DLL3 BiTE® molecule for proof of concept (Fig. 1A). This anti-DLL3

3 BiTE® molecule had high binding affinity for human and NHP DLL3 and CD3, with equilibrium

4 dissociation constants (KD) of 3.0 nM and 3.1 nM for human and NHP DLL3, and 4.6 nM and 4.4

5 nM for human and NHP CD3, respectively. The anti-DLL3 BiTE® molecule demonstrated potent

6 activity in TDCC assays against HEK-293 cells transiently transfected to express DLL3, with a

7 half maximal effective concentration [EC50] value of 2.2 pM (Fig. 1B). This activity was DLL3-

8 dependent, as no cell killing activity was observed against mock-transfected HEK-293 cells

® 9 (EC50 > 1 nM; Fig. 1B). The anti-DLL3 BiTE molecule induced cell killing across SCLC cell

10 lines with EC50 values of 18–203 pM (Fig. 1C). These studies validate the approach of targeting

11 DLL3-expressing target cells with a BiTE® molecule.

12 Anti-DLL3 BiTE® molecule antitumor activity in xenograft models

13 The in vivo activity of the anti-DLL3 BiTE® molecule was initially assessed in admixture

14 xenograft models, where SCLC tumor cells mixed with human T cells were implanted

15 subcutaneously into mice. The anti-DLL3 BiTE® molecule was administered daily due to its short

16 half-life. An anti-Mec14 BiTE® molecule (35) was used as a negative control. In the SHP-77

17 xenograft model, which expresses 3,222 DLL3 molecules per cell (Table S4), mice treated daily

18 with 0.5 mg/kg of the anti-DLL3 BiTE® molecule showed 89% tumor growth inhibition (TGI) after

19 15 days compared with mice treated with the anti-Mec14 BiTE® molecule (P = 0.0001; Fig. 1D).

20 In the NCI-H82 xenograft model, which expresses 1,290 DLL3 molecules per cell, mice treated

21 daily with the anti-DLL3 BiTE® molecule at 0.5 mg/kg had 75% TGI compared with mice treated

22 with the control molecule (P < 0.0001; Fig. 1E). Together, these studies indicate that an anti-

23 DLL3 BiTE® molecule can effectively engage human T cells in xenograft tumors to inhibit tumor

24 growth.

1 AMG 757 binding and activity in vitro

2 AMG 757 was designed to retain the potency and sensitivity of the anti-DLL3 BiTE® molecule

3 and to have an increased serum half-life to facilitate longer dosing intervals. The extended half-

4 life of AMG 757 results from incorporation of a stable, effector-functionless Fc domain at the

5 carboxy terminus of the molecule (Fig. 2A) (36).

6 The binding affinity of AMG 757 to human and NHP DLL3 was 0.64 ± 0.05 nM and 0.50 ± 0.01

7 nM, respectively, and AMG 757 binding affinity to human and NHP CD3 was 14.9 ± 0.4 nM and

8 12.0 ± 0.3 nM, respectively (Table S5). TDCC assays demonstrated that the in vitro cell potency

9 of AMG 757 against DLL3-positive SCLC cell lines was similar to that of the anti-DLL3 BiTE®

10 molecule and specific for DLL3-positive cells, with no evidence of cytotoxicity against the NCI-

11 H460 cell line that does not express DLL3 (Fig. 2B). AMG 757 effectively engaged human T

12 cells to kill SCLC cell lines, including those with very low DLL3 expression levels (<1,000

13 molecules/cell; Fig. 2C, Table S4). AMG 757 induced potent cell killing with either human or

14 NHP effector cells, with EC50 values within 1- to 7-fold for each cell line, confirming the cross-

15 reactivity of AMG 757 with NHP CD3 (Fig. 2D, Table S5).

16 AMG 757-dependent cytotoxicity was associated with hallmarks of BiTE® molecule target

17 engagement, including T cell activation, cytokine production, and release of cytotoxic granules

18 (Fig. 3). AMG 757 increased granzyme B levels and cytotoxicity over time, with maximal signal

19 observed at 48 hours (Fig. 3A). Markers of T-cell activation or inflammation, CD69, CD71, PD-

20 1, and PD-L1 (37-39) were upregulated following AMG 757 treatment (Fig. 3B). AMG 757-

21 mediated redirected lysis was accompanied a production of proinflammatory cytokines (Fig.

22 3C). DLL3 cell surface expression on the corresponding human tumor cell lines is shown in Fig.

23 3D and in Table S4. Together, these data demonstrate the AMG 757 mechanism of action.

1 Anti-DLL3 BiTE® molecules are well tolerated in NHP

2 The cross-reactivity of the anti-DLL3 BiTE® molecule and AMG 757 with NHP DLL3 and CD3

3 established NHP as a relevant model for evaluation of the tolerability of these molecules in vivo.

4 The anti-DLL3 BiTE® molecule was evaluated in an exploratory, step-dose, nonterminal safety

5 study in NHP. Animals received the anti-DLL3 BiTE® molecule by cIV infusion at doses up to

6 100 µg/day for 7 days. All doses evaluated were well tolerated, consistent with the idea that the

7 low level, cytoplasmic DLL3 expression in normal NHP tissues is inaccessible to BiTE® molecule

8 binding.

9 The pharmacokinetic (PK) profile of AMG 757 in NHP was characterized in a single-dose study.

10 After a single 12 µg/kg dose of AMG 757, serum concentrations of AMG 757 decreased in a

11 biphasic manner, with a mean clearance of 0.487 mL/h/kg and a steady-state volume of

12 distribution of 146 mL/kg (Fig. 4). The maximum serum concentration was 0.239 µg/mL and the

13 area under the concentration-time curve was 16.7 h*µg/mL. The trough exposure level after 336

14 hours (14 days) was approximately 10-fold higher than the mean in vitro EC50 of AMG 757

15 across SCLC cell lines. The mean half-life of AMG 757 was 234 hours (9.8 days). These data

16 confirm that AMG 757 has an extended half-life relative to the anti-DLL3 BiTE® molecule.

17 AMG 757 was assessed in a 1-month repeat dose toxicology study in NHP. Weekly doses of

18 AMG 757 up to 4.5 mg/kg were well tolerated and no AMG 757-related adverse findings were

19 observed (40). Taken together, the NHP studies suggest that AMG 757 has the potential to

20 achieve high exposures that may be required for effective antitumor activity in the clinic.

21 Anti-DLL3 BiTE® molecules drive tumor regression in mouse models of SCLC

22 To demonstrate proof of concept of AMG 757 in vivo, we evaluated antitumor activity in an

23 admixture WM266-4 xenograft model, where human T cells and WM266-4 tumor cells were

24 mixed and implanted subcutaneously in immunodeficient mice. Administration of AMG 757 at

1 0.1, 0.5, or 3 mg/kg every 5 days significantly inhibited tumor growth in this model (Fig. S4). We

2 next used PDX models to assess the activity of AMG 757 against established SCLC tumors.

3 PDX tumors replicate the heterogeneity and architecture of human tumors in a mouse model

4 (41), and systemic administration of human T cells to mice bearing PDX tumors enables

5 assessment of T cell-mediated antitumor activity, as AMG 757 does not cross react with mouse

6 CD3. We evaluated AMG 757 activity in the LXFS 1129 and LXFS 538 PDX models of SCLC,

7 which express DLL3 at levels similar to that of NCI-H82 cells (Fig. S5A, B).

8 Immunocompromised mice bearing established LXFS 1129 tumors received a single

9 administration of human T cells and were then treated with AMG 757 once weekly for 3 weeks.

10 AMG 757 treatment led to 83% tumor regression, including complete responses in 8 of 10 mice

11 by day 23, and an overall significant reduction in tumor volume compared with that in mice

12 which received a control HLE BiTE® molecule (P < 0.0001) (Fig. 5A). In the LXFS 538 model,

13 AMG 757 treatment induced 98% tumor regression, including complete responses in 8 of 10

14 mice by day 21, and an overall significant reduction in tumor volume compared with that in mice

15 which received the control HLE BiTE® molecule (P < 0.0001) (Fig.5B). The mice in the LXFS

16 538 study treated with AMG 757 were observed through day 32 (17 days after the last AMG 757

17 dose), at which point 9 of 10 mice had complete responses, with one mouse having a residual

18 (<5 mm3) mass that had remained static for 2 weeks. At this last time point, both the human T

19 cells and AMG 757 would have been cleared from circulation.

20 We developed orthotopic SCLC models to further explore AMG 757 antitumor activity. These

21 models recapitulate the biologic compartment of primary SCLC tumors and, like the PDX model,

22 require that human T cells administered systemically traffic to the tumor site for BiTE® molecule

23 target engagement. Consistent with primary SCLC tumors, the SHP-77 orthotopic model is

24 characterized by tumor growth in the lungs but the lesions are not visible macroscopically. In

25 contrast, the NCI-H82 orthotopic model mimics SCLC metastatic disease with discrete, visible

1 tumors primarily in the liver. Both models used cell lines engineered to express luciferase to

2 enable visualization of tumor burden by BLI. Human T cells were administered once, and BiTE®

3 molecules were administered weekly by IV infusion to immunocompromised mice bearing

4 established orthotopic tumors.

5 AMG 757 treatment significantly inhibited growth of established orthotopic SHP-77 lung tumors

6 (P < 0.0008; Fig. 5C, D). BLI imaging on day 22 revealed that mice treated with AMG 757

7 exhibited significant TGI (Fig. 5D). The minimal BLI signal that persisted in the AMG 757-

8 treated mice at the end of the study might reflect residual nodules or cell debris. Tumors in mice

9 treated with vehicle alone or with a control HLE BiTE® molecule continued to grow (Fig. 5C, D).

10 In the NCI-H82 orthotopic liver model, AMG 757 treatment significantly inhibited growth of liver

11 metastases compared with vehicle or control HLE BiTE® molecule-treated groups at day 22 (P <

12 0.0001; Fig. 5E). BLI imaging on day 22 revealed a marked decrease in tumor mass after AMG

13 757 treatment (Fig. 5F). Strikingly, no lesions were visible in the liver at day 23 following AMG

14 757 treatment, suggesting complete response to treatment (Fig. 5G, H). In contrast, the vehicle

15 and control HLE BiTE® molecule-treated cohorts contained multiple liver lesions (mean of 41.5

16 and 41.8 lesions, respectively; P < 0.0001; Fig. 5G, H).

17 AMG 757 engages tumor-infiltrating T cells

18 The pharmacodynamic effects of AMG 757 treatment on T cells infiltrating SCLC tumors was

19 evaluated. In the LXFS 538 PDX model, we used flow cytometry to assess T cell numbers and

20 markers of activation from T cells isolated from disaggregated tumor tissue. A single dose of

21 AMG 757 led to a statistically significant increase in the absolute number of human CD4+ and

22 CD8+ T cells in the tumors at 4 days post-treatment compared with treatment with the control

23 HLE BiTE® molecule (CD4+, mean 77,098 vs 1,601 cells; P = 0.004; CD8+, mean 263,289 vs

24 2,686 cells; P = 0.012; Fig. 6A). The T-cell activation markers CD25, CD69, and PD-1 were

1 significantly upregulated (P < 0.0001) in CD4+ and CD8+ T cells in the AMG 757-treated group

2 compared with the control HLE BiTE® molecule-treated group in LXFS 538 PDX tumors (Fig.

3 6B, C).

4 Similarly, in the SHP-77 orthotopic model, a significant increase in human CD4+ and CD8+ T

5 cell counts in the disaggregated lung tissue occurred 7 days post-treatment with AMG 757

6 compared with those from the control HLE BiTE® molecule-treated group (CD4+, mean 60 vs

7 7.9 cells/mg of lung tissue; P = 0.013; CD8+, mean 117.8 vs 16.7 cells/mg of lung tissue; P =

8 0.018; Fig. 6D), and 72 hours after administration of AMG 757 in metastatic liver lesions from

9 the NCI-H82 xenograft SCLC model (CD4+, mean of 1,080 vs 78.2 cells/mg of tumor tissue; P <

10 0.0001; CD8+, mean of 1,597 vs 89.6 cells/mg of tumor tissue; P < 0.0001; Fig. 6E) when

11 compared with the number of cells from groups receiving HLE BiTE® molecule.

12 While a significant upregulation of the T-cell activation markers CD25, CD69, PD-1, and 4-1BB

13 was observed on T cells from metastatic liver lesions from the AMG 757-treated group in the

14 NCI-H82 model, this increase was not observed in T cells from the disaggregated lung tissue

15 from the SHP-77 orthotopic model (Fig. 6F, G, and Figure S6). This may be due to the fact that

16 the total population of lung-resident T cells was analyzed in the SHP-77 orthotopic model rather

17 than T cells specific to the lung tumors.

18 NCI-H82 tumors from mice treated with AMG 757 and the control HLE BiTE® molecule were

19 compared to evaluate tumor morphology and the spatial relationship between infiltrating T cells

20 and tumor cells. In hematoxylin- and eosin-stained sections, NCI-H82 tumors treated with

21 AMG 757 had a qualitative increase in infiltrating lymphocytes dispersed throughout the tumor

22 and in the tumor periphery. While the control HLE BiTE® molecule-treated tumors were well-

23 demarcated and composed primarily of viable neoplastic cells, AMG 757-treated tumors

24 exhibited viable and degenerate inflammatory cells, necrotic cellular debris, and collapsed

1 stroma in the periphery (Fig 6H). Immunohistochemistry demonstrated that the infiltrating

2 lymphocytes were CD4+ and CD8+ T cells (Fig. 6I). Collectively, the orthotopic models

3 demonstrate that AMG 757 can promote T-cell trafficking to tumors in different compartments

4 and engage T cells to DLL3-expressing SCLC cells, enabling complete antitumor responses

5 against established SCLC tumors.

1 Discussion

2 AMG 757 is a first-in-class HLE BiTE® immuno-oncology therapy targeting DLL3 for the

3 treatment of SCLC. Here, we demonstrate that AMG 757 engages T cells to induce potent

4 redirected lysis of SCLC cells in vitro and significant antitumor activity in mouse models of

5 primary and metastatic SCLC. In vitro, AMG 757 had potent cell killing activity against SCLC

6 cells with as low as <1000 DLL3 receptors per cell. In vivo, AMG 757 engaged human T cells

7 administered systemically and DLL3-expressing tumor cells to promote tumor regression. In our

8 models, AMG 757 monotherapy cleared established tumors including visible metastases, and

9 only residual nodules were detected even in the LXFS 538 model, where the mice remained on

10 study 17 days after the last treatment of AMG 757. However, as our tumor models use

11 immunocompromised mice, and the human T cells administered once at the start of our studies

12 do not persist beyond a few weeks, these models are not suitable for longer-term evaluation

13 necessary to uncover mechanisms of resistance to AMG 757. The impact of DLL3 expression

14 levels and the tumor microenvironment on AMG 757 activity and potential resistance

15 mechanisms will be further assessed in SCLC patients.

16 A 1-month repeat dose NHP toxicology study showed that AMG 757 was well tolerated at 4.5

17 mg/kg, a dose with exposure levels that far exceed the mean in vitro cell EC50 values, with no

18 AMG 757-related adverse findings. Given the high affinity binding of AMG 757 to NHP DLL3

19 and CD3, and the potent activity of NHP effector cells in redirected lysis of SCLC tumor cells,

20 the in vivo safety profile strongly suggests that DLL3 expressed on normal tissues is largely

21 inaccessible to AMG 757 target engagement. BiTE® molecules may access targets expressed in

22 brain, as blinatumomab has been detected in the brain and can be associated with neurologic

23 events, and an EGFRvIII-targeting BiTE® molecule, AMG 596, is in development for

24 glioblastoma (42-44).

1 The safety profile of AMG 757 in NHP is very different from that of another DLL3-targeted

2 therapy, the antibody drug conjugate rovalpituzumab tesirine. Safety-related findings in

3 preclinical toxicology studies with rovalpituzumab tesirine included myelosuppression, kidney

4 degeneration, and thickening and hyperpigmentation of the skin (29). These adverse effects

5 were attributed to the cytotoxic payload of the molecule, pyrrolobenzodiazepine (PBD), and

6 were not related to DLL3 expression (45). Despite early clinical activity of rovalpituzumab

7 teserine (12%–18% objective response rates) (45,46), treatment was associated with dose-

8 limiting adverse events, including pleural and pericardial effusion and skin reactions, which

9 limited treatment to two cycles on average (45). These findings were also attributed to PBD, and

10 development of rovalpituzumab tesirine was halted after a phase 3 study showed no survival

11 benefit (14). The toxicity profile of rovalpituzumab tesirine in preclinical and clinical studies is

12 therefore not associated with DLL3 expression (46). While recent advances in linker technology,

13 antibody design, and payload optimization may improve the therapeutic index of an ADC

14 targeting DLL3, the relatively low abundance of DLL3 suggests that it could be challenging to

15 deliver sufficient amounts of a toxic payload to DLL3 positive SCLC tumors without dose-limiting

16 toxicity caused by unconjugated payload. The combination of activity in preclinical tumor models

17 and preliminary safety data in cynomolgus monkeys highlight the promise of targeting DLL3 with

18 a BiTE® molecule. In addition to AMG 757, chimeric antigen receptor (CAR)-T cells targeting

19 DLL3 in SCLC and other neuroendocrine tumors are in development, and DLL3-targeted

20 radioimmunoconjugates are also being explored (31,47).

21 The treatment paradigm in SCLC has recently changed with the approval of PD-1/ PD-L1

22 immune checkpoint inhibitors in multiple settings, including as part of first-line therapy in

23 combination with chemotherapy (8,48). Although these approvals represent a significant

24 advancement in SCLC treatment, the overall response rates remain low. AMG 757 provides an

25 option for therapeutic targeting of DLL3-expressing SCLC cells by a mechanism that is

1 completely distinct from that of immune checkpoint inhibitors. AMG 757 demonstrates

2 engagement of T cells and direct T cell-mediated killing of established tumors, and also the

3 potential to promote T-cell infiltration into tumors. AMG 757 therefore may also be considered

4 for combination therapy with anti-PD-1/PD-L1 inhibitors in patients where it may enhance the

5 activity of immune checkpoint inhibitors (15,49); blinatumomab and other BiTE® molecules have

6 been shown to upregulate the PD-1/PD-L1 axis and patients may benefit from combination

7 therapy with immune checkpoint inhibitors (50). AMG 757 provides a new option for SCLC

8 therapy with a compelling nonclinical safety:efficacy profile, and clinical evaluation in SCLC

9 patients is ongoing (NCT03319940).

1 Acknowledgments

2 The results shown here are based in part on data generated by the TCGA Research Network 3 (https://www.cancer.gov/tcga).

4 The authors acknowledge Karen Hettwer, Rodolfo Yabut, Roberto Guzman, David Smith,

5 Joachim Wahl, Kathy Manchulenko, Tao Osgood, Melody Richardson, and Amy Gilbert for

6 technical support. Medical writing support was provided by Ben Scott, PhD (Scott Medical

7 Communications, LLC), Sukanya Raghuraman, PhD (Cactus Life Sciences, part of Cactus

8 Communications), Micah Robinson, PhD (Amgen Inc.), and Jacqueline Sayyah (Amgen, Inc.).

9 This study was funded by Amgen Inc. We thank Mark Salvati, PhD, and Marie-Anne Damiette

10 Smit, MD, MS, for critical review of the manuscript.

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1 Figure Legends

2 Figure 1

3 The canonical anti-DLL3 BiTE® molecule exhibits DLL3-specific activity in vitro and in 4 vivo. A, Schematic representation of the BiTE® molecule format (light blue, anti-DLL3 scFv; 5 green, anti-CD3 scFv). B, Dose-response curves of the anti-DLL3 BiTE® molecule against HEK- 6 293 cells transiently transfected with a DLL3-expressing vector (HEK-293/DLL3) or mock- 7 transfected (HEK-293/mock). Cells were co-cultivated in duplicate with preactivated human pan- 8 T cells at an E:T cell ratio of 10:1 and a dose range of anti-DLL3 BiTE® molecule for 20 hours. 9 Specific cytotoxicity was assessed by flow cytometry. C, Dose-response curves of the anti-DLL3 10 BiTE® molecule against representative luciferase-labeled SCLC cell lines. Cells were co- 11 cultivated in duplicate with human pan-T cells at an E:T cell ratio of 10:1 and increasing 12 concentrations of anti-DLL3 BiTE® molecule for 48 hours. Specific cytotoxicity was assessed 13 with a luminescence readout. D,E The anti-DLL3 BiTE® molecule inhibits growth of SHP-77 14 tumors (D) and NCI-H82 tumors (E). Tumor cells mixed with human T cells were implanted 15 subcutaneously (day 0) and then treated with either the anti-DLL3 BiTE® molecule or a control 16 (nontargeting) Mec14 BiTE® molecule daily starting on day 1 of the study. ***P = 0.0001; ****P < 17 0.0001. Data shown in Panel C represent mean values and standard error of the mean for 18 duplicate samples. Data in Panels D and E represent mean ± SEM, n = 10 mice/cohort. Data in 19 Panels D and E are representative of two and one independent studies, respectively.

1 Figure 2

2 AMG 757 has potent, specific cytotoxic activity against DLL3-expressing SCLC cell lines 3 in vitro. A, Schematic representation of the HLE BiTE® format (light blue, anti-DLL3 scFv; 4 green, anti-CD3 scFv; dark blue, Fc domain). B, AMG 757 has similar activity in vitro as the 5 anti-DLL3 BiTE® molecule. BiTE® molecules were incubated with human pan-T cells and DLL3- 6 positive SHP-77 cells or DLL3-negative NCI-H460 cells at a 10:1 E:T cell ratio, and cell viability 7 was assessed by a luciferase readout after 48 hours. C, Dose-response curves of AMG 757 8 against representative SCLC cell lines. Cells were co-cultivated with human PBMC from 9 multiple human donors at an E:T cell ratio of 5:1 and a dose range of AMG 757 for 48 hours. 10 Target cell lysis was assessed by flow cytometry. D, Cross-reactivity of AMG 757 with NHP 11 effector cells. AMG 757 was incubated with NHP PBMC (cyPBMC #F1, #F2, #F5 and #F6) and 12 human SCLC target cells at a 5:1 E:T cell ratio for 48 hours. Cell viability was assessed by flow 13 cytometry. The mean values and standard error of the mean for duplicate samples are shown in 14 Panels B, C, and D

1 Figure 3

2 AMG 757 activates T cells and promotes cytokine production and T cell-redirected lysis. 3 A, Granzyme B activation and cytotoxicity of AMG 757 against the SHP-77 cell line co-cultivated 4 with human PBMC at time points from 4 to 72 hours (E:T, 2:1). B, AMG 757-induced expression 5 of activation markers on human T cells. SHP-77 cells were co-cultivated with purified human 6 CD3+ T cells at an E:T cell ratio of 5:1 with a dose range of AMG 757 for 48 hours. T-cell 7 activation was evaluated by flow cytometry. C, AMG 757-induced cytokine release by human 8 PBMC. Human PBMC (n = 2) were co-cultivated with NCI-H2171, NCI-H889, and SHP-77 tumor 9 cells at an E:T cell ratio of 5:1 and a dose range of AMG 757 concentrations for 48 hours. 10 Levels of cytokines in the cell culture supernatants were measured with the human CBA 11 Th1/Th2 II kit (Becton Dickinson). IL, interleukin; TNF, tumor necrosis factor; IFN, interferon. D, 12 Flow cytometry analysis of DLL3 expression in NCI-2171, NCI-H889 and SHP-77 cell lines. 13 Unstained, cells that were not stained with any antibody; 2nd Ab, cells stained with secondary 14 antibody (anti-mouse FITC) only; DLL3, cells stained with primary DLL3 antibody and secondary 15 anti-mouse FITC antibody.

1 Figure 4

2 AMG 757 exhibits an extended serum half-life. The PK profile of a single 12 μg/kg 3 intravenous bolus infusion of AMG 757 was analyzed in NHP. AMG 757 serum concentrations 4 at the time points indicated were measured by an immunoassay measuring total levels of AMG 5 757 and were interpolated from a standard curve.

1 Figure 5

2 AMG 757 inhibits growth of established PDX and orthotopic SCLC tumors. A,B, Evaluation 3 of AMG 757 antitumor activity against PDX tumors. NOG mice bearing established patient- 4 derived LXFS 1129 (A) and LXFS 538 (B) SCLC tumors were implanted with human T cells on 5 study day 0 and then treated with 3 mg/kg AMG 757 or control HLE BiTE® molecule once 6 weekly for 3 weeks beginning on day 1. ****P < 0.0001. C, Evaluation of AMG 757 activity 7 against lung tumors in the SHP-77 orthotopic model. NSG mice were implanted with human T 8 cells on study day 7 and then treated with 3 mg/kg AMG 757 or control HLE BiTE® molecule 9 once weekly for 2 weeks beginning on day 8. BLI (photons/second) from a region of interest 10 (ROI) on the upper chest/lung region of the mice is shown. ***P < 0.0008. Data are 11 representative of two independent experiments. D, Luminescence images of three 12 representative mice from each group in (C) at day 7 (pre-treatment) and day 22 are shown. E, 13 Evaluation of AMG 757 activity against metastatic liver lesions in the NCI-H82 orthotopic model. 14 BLI (photons/second) from a ROI on the central chest region of each mouse is shown. ****P < 15 0.0001. F, Luminescence images of three representative mice from each group from (E) at day 16 7 (pre-treatment) and day 22 are shown. G, Photos of three representative livers from each 17 group from (E) at day 23 are shown. H, The number of visible liver lesions from different 18 treatment groups in (E) on day 23 of study were compared. ****P < 0.0001. Data in panels A–C 19 and E represent mean ± SEM, n = 9–10 mice/cohort. H: Data represent mean ± SD, 20 n = 10 mice/cohort. Data described in Panels A, B, E, and H were derived from one 21 independent study each. Red arrows in Panels A, B, C, and E indicate AMG 757 or control HLE 22 BiTE® molecule or Vehicle dosing.

1 Figure 6

2 AMG 757 induces T-cell activation and tumor infiltration. A, Evaluation of T-cell infiltration 3 into LXFS 538 PDX tumors 96 hours after treatment with AMG 757 or a control HLE BiTE® 4 molecule. *P = 0.012, **P = 0.004. B, Activation of human CD4+ T cells isolated from LXFS 538 5 PDX tumors 96 hours after treatment with AMG 757 or a control HLE BiTE® molecule. **P = 6 0.001, ***P < 0.0005. C, Activation of human CD8+ T cells isolated from LXFS 538 PDX tumors 7 96 hours after treatment with AMG 757 or a control HLE BiTE® molecule. **P = 0.002, ****P < 8 0.0001. D, Evaluation of T-cell infiltration into SHP-77 tumors in lungs 168 hours after treatment 9 with AMG 757 or a control HLE BiTE® molecule. *P < 0.05. E, Evaluation of T-cell infiltration into 10 NCI-H82 metastatic liver tumors 72 hours after treatment with AMG 757 or a control HLE BiTE® 11 molecule. ****P < 0.0001. F, Activation of human CD4+ T cells isolated from mouse livers 12 harboring NCI-H82 tumors 72 hours after treatment with AMG 757 or a control HLE BiTE® 13 molecule. **P = 0.001, ****P < 0.0001. G, Activation of human CD8+ T cells isolated from 14 mouse livers harboring NCI-H82 tumors 72 hours after treatment with either AMG 757 or a 15 control HLE BiTE® molecule. ****P < 0.0001 H, Representative photomicrographs of 16 hematoxylin and eosin-stained liver with NCI-H82 orthotopic tumors 72 hours after treatment 17 with AMG 757 or a control HLE BiTE® molecule. Magnification is 8× (upper left and upper right; 18 scale bar = 100 µm) and 40× (bottom left and bottom right; scale bar = 50 µm). T = NCI-H82 19 tumor; L = normal liver; dotted line = margin between NCI-H82 tumor and normal liver; * = tumor 20 periphery with viable and degenerate inflammatory cells, necrotic cellular debris and collapsed 21 stroma. I, Representative photomicrographs of immunohistochemical staining for CD4 and CD8 22 (as shown by brown staining) in livers with NCI-H82 orthotopic tumors from mice treated with 23 AMG 757 or a control BiTE® molecule. Magnification is 8× (scale bar = 100 µm). Data represent 24 mean ± SD, n = 4–6 mice/cohort. The data described in Panels A–C, H, and I represent a single 25 study, data in Panels D–G represent 2 independent studies.

AMG 757, a Half-Life Extended, DLL3-Targeted Bispecific T-Cell Engager, Shows High Potency and Sensitivity in Preclinical Models of Small Cell Lung Cancer

Michael J. Giffin, Keegan Cooke, Edward K Lobenhofer, et al.

Clin Cancer Res Published OnlineFirst November 17, 2020.

Updated version Access the most recent version of this article at: doi:10.1158/1078-0432.CCR-20-2845

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