anti-DLL4 Antibody Research Articles

A phase 1b study of the anti-cancer stem cell agent demcizumab (DEM) and gemcitabine (GEM) +/- nab-paclitaxel in patients with pancreatic cancer.

341 Background: Delta-like ligand 4 (DLL4) activates the Notch pathway. DEM is a humanized anti-DLL4 antibody that inhibits tumor growth & decreases cancer stem cell frequency in human tumor xenograft models. DEM also has an antiangiogenic effect & synergistic activity when combined with GEM & nab-paclitaxel in pt derived xenograft models of pancreatic cancer. Methods: Pts with 1st line pancreatic cancer were enrolled. Pts in cohorts 1-3 received DEM (2.5 every 2 or 4 wks or 5 mg/kg every 4 wks including 3 truncated pts) & GEM 1000 mg/m2 7 of 8 wks, then 3 of 4 wks. Pts in cohorts 4, 5, 6 & 7 received truncated DEM (2.5, 3.5 or 5 mg/kg every 2 wks through Day 70) & nab-paclitaxel 125 mg/m2 + gemcitabine 1000 mg/m2 3 of 4 wks. The primary objective was to determine the MTD. Other objectives were safety, efficacy, immunogenicity, PK & biomarkers. Results: Fifty-six pts were enrolled; 8, 8, 8, 6, 8, 9 & 9 pts received 2.5 mg/kg every 2 wks, 2.5 mg/kg every 4 wks, 5 mg/kg every 4 wks, 2.5 mg/kg every 2 wks (truncated), 5 mg/kg every 2 wks (truncated), 3.5 mg/kg every 2 wks (truncated) & 3.5 mg/kg every 2 wks (truncated), respectively. Related AEs in > 20% of pts were fatigue (36%), nausea (32%), vomiting (23%), hypertension (21%) & diarrhea (20%). Hypertension was managed with anti-hypertensives. Increased BNP is an early indicator of the cardiac effects of DEM & mildly elevated values were used to initiate a cardioprotective ACE inhibitor or carvedilol. Two pts who received DEM continuously developed reversible pulmonary hypertension & 1 of these pts developed heart failure. As a result, DEM was limited to 70 days in cohorts 4, 5, 6 & 7. In cohorts 1-3, 4 of 16 (25%) pts had a PR. In cohorts 4, 5, 6 & 7, 14 of 28 (50%) pts had a PR & 11 had SD. The truncated DEM pts had a median PFS of 9.0 mos (95% CI: 3.7 mos-NR) & a median survival of 10.1 mos (95% CI: 6.5-16.2 mos), respectively. Conclusions: This therapy was generally well tolerated with fatigue, nausea & vomiting being the most common related AEs. Truncated DEM dosing (i.e., limited to 70 days) avoided clinically significant cardiopulmonary toxicity. Encouraging clinical activity was observed. Biomarker analysis showed modulation of the Notch pathway. Final data will be presented. Clinical trial information: NCT01189929.

Demcizumab: Anti-DLL4 monoclonal antibody, treatment of non-small cell lung cancer, treatment of pancreatic cancer

Demcizumab: Anti-DLL4 monoclonal antibody, treatment of non-small cell lung cancer, treatment of pancreatic cancer

2016 Gastrointestinal Cancers Symposium: update on pancreatic cancer.

Agent Mechanism of action/target 196 [9] BBI-608 Cancer stemness inhibitor 341 [10] Demcizumab Humanized anti-DLL4 antibody 334 [11] Cabozantinib c-Met inhibitor 371 [12] Sonidegib Smoothened receptor inhibitor 385 [13] Atu027 Protein kinase N3 (PKN3) inhibitor 419 [14] Apatorsen Heat shock inhibitor

MMGZ01, an anti-DLL4 monoclonal antibody, promotes nonfunctional vessels and inhibits breast tumor growth

Increasing evidence suggests that DLL4 (Delta-like 4)-Notch signaling plays a critical role in cell fate determination and differentiation in tissues. Blocking DLL4-Notch signaling results in inhibition of tumor growth, which is associated with increased nonfunctional vessels and poor perfusion in the tumor. We successfully generated a human DLL4 monoclonal antibody MMGZ01 that binds specifically to DLL4 to disrupt the interaction between DLL4 and Notch1. MMGZ01 showed high affinity to DLL4 to inhibit the DLL4-mediated human umbilical vein endothelial cell (HUVEC) phenotype. Furthermore, MMGZ01 stimulated HUVEC vessel sprouting and tubule formation in vitro. In addition, MMGZ01 had a pronounced effect in promoting immature vessels and reduced breast cancer cell growth in vivo. Finally, MMGZ01 treatment inhibited the proliferation of breast cancer cells, induced tumor cell apoptosis, suppressed mammosphere formation, decreased CD44+/CD24− cell population, and reduced epithelial mesenchymal transition (EMT). These findings suggest that antagonism of the DLL4-Notch signaling pathway might provide a potential therapeutic approach for breast cancer treatment.

Abstract 255: Dual targeting of Delta-like ligand 4 (DLL4) and programmed death 1(PD1) inhibits tumor growth and generates enhanced long-term immunological memory

Abstract Blocking DLL4, a Notch ligand, effectively inhibits tumor growth by increasing non-functional angiogenesis and decreasing the cancer stem cells (CSC) population. We are currently testing an anti-DLL4 antibody, demcizumab, in Phase1B trials in NSCLC, pancreatic, and ovarian cancer. DLL4 is also known to modulate immune responses. In the current study we examine the impact of anti-DLL4 on anti-tumor immune responses as a single agent and in combination with the key immune checkpoint inhibitor Programmed Cell Death Protein 1 (PD1). While the recent clinical success of PD1 inhibitors represents a new and promising cancer immunotherapeutic approach, high initial response rates are often associated by a lack of long-term, durable effects in a significant number of patients. Therefore, we hypothesized that dual blockade of DLL4 and PD1 might further impact tumor growth by further enhancing anti-tumor immune immunity. Our data demonstrates that dual blockade of DLL4 and PD1 using antibodies not only reduces tumor growth, but also led to tumor rejection in ∼50% in CT26WT tumor-bearing mice, similar to those treated with anti-PD1 alone (no tumor rejection was observed with anti-DLL4 alone). Anti-PD1 increased specific CD8+ T cell-mediated IFN-γ production while decreasing IL6. Anti-DLL4 treatment reduced IL17 production. Interestingly, only the dual blockage led to increased production of IL2 by splenocytes. Since IL2 is required for secondary population expansion of CD8+ memory T cells, increased IL2 in the combination group suggests potential for increased T cell activation, maintenance and memory T cell function, as compared to single agent anti-DLL4 and anti-PD1. While anti-PD1 reduced inhibition of CD4+ T cell proliferation by Tregs, the dual blockade significantly reduced Treg-mediated CD8+ T cell suppression. Furthermore, both effector and memory CD8+ T cell frequencies were increased within the total CD8+ T cell population. Interestingly, anti-PD1 decreased granulocytic MDSCs, while anti-DLL4 reduced monocytic MDSCs. Mice cured with single-agent anti-PD1 and anti-DLL4/anti-PD1 combination treatments were protected from series of re-challenge with tumor cells, suggesting the existence of immunologic memory. Interestingly, more mice were protected from tumor re-challenge when both DLL4 and PD1 were blocked, as compared to PD1 alone. Surprisingly, mice previously treated with the anti-DLL4/anti-PD1 combination produced more IL2, clearly indicating the role of DLL4 blockade in enhancing anti-tumor immunity. Therefore, these results show that dual targeting of DLL4 and PD1 may be an effective and durable cancer therapy by increasing anti-tumor immune response and promoting long-term immunological memory. Citation Format: Minu Srivastava, Christopher L. Murriel, Julie Roda, Hyun-Bae Jie, Fumiko Axelrod, Ming-Hong Xie, Rui Yun, Erin Mayes, Trevor Bentley, Belinda Cancilla, Raymond Tam, Tracy Tang, Ann Kapoun, John Lewicki, Tim Hoey, Austin Gurney, Angie Inkyung Park. Dual targeting of Delta-like ligand 4 (DLL4) and programmed death 1(PD1) inhibits tumor growth and generates enhanced long-term immunological memory. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 255. doi:10.1158/1538-7445.AM2015-255

Highlights of This Issue

The Delta-Notch pathway contributes to tumor angiogenesis, cell growth and differentiation, and stem cells self-renewal. Preclinically, Dll4 blockade causes dysfunctional vasculature and diminished perfusion. This phase I first-in-human study tested enoticumab, a novel anti-Dll4 monoclonal antibody in patients with refractory solid tumors. Enoticumab was associated with several reversible cardiovascular adverse events but otherwise was well tolerated. Antitumor activity was seen in patients with ovarian cancer, bronchoalveolar NSCLC with β-catenin mutation, and colorectal cancer with FAP syndrome. Given the negative feedback by Dll4/Notch on the VEGF/VEGFR axis, combination therapies with anti-VEGF agents are expected to provide increased efficacy, and should be tested in the clinic.CD44 is associated with tumor development, progression, metastasis, and drug resistance in several tumor indications. Thus, blocking CD44 in tumor patients is regarded as a promising approach in anticancer therapies. However, CD44 represents a family of proteins with diverse functions originating from alternative splicing. Birzele and colleagues demonstrate how preclinical in vitro and in vivo characterization of CD44 isoform expression led to the identification of CD44s as a potential response prediction marker to anti-CD44 treatment (RG7356 antibody). This was confirmed in data from a phase I clinical trial where patients were treated with RG7356.Transformed cells are dependent on methionine for growth and survival by mechanisms that are poorly understood. In this study, Strekalova and colleagues demonstrate that methionine deprivation exposes a targetable defect in triple-negative breast cancer cells, but not untransformed cells, by increasing cell surface expression of the proapoptotic TNF-related apoptosis-inducing ligand receptor-2 (TRAIL-R2), thereby enhancing their sensitivity to TRAIL-R2 agonists in vitro and in vivo. These findings indicate that metabolic stress exposes distinctive vulnerabilities in transformed cells that can be targeted with rationally selected therapies and provide the foundation for a clinical trial combining dietary methionine restriction and TRAIL-R2 agonists.Papillary renal cell cancer (PRCC) is a subset of RCC with poor prognosis for patients with nonlocalized disease. Current treatment options, including the standard of care for RCC, provide only modest benefit. Recently, the molecular underpinnings of clinical PRCC have been evaluated describing a central role for MET. Schuller and colleagues used two independent patient-derived PRCC xenograft models, both harboring MET copy number gain similar to that seen in patients, for therapeutic testing. The authors demonstrate that targeted agents for MET inhibition, including AZD6094 (savolitinib, HMPL-504) induce tumor regressions and may be more efficacious than current therapeutic approaches warranting further clinical investigation.

114P - A Phase 1B Study of Anti-Dll4 (DELTA-LIKE LIGAND 4) Antibody Demcizumab (DEM) with Pemetrexed (PEM) and Carboplatin (CARBO) in Patients with 1St-Line Non-Squamous Nsclc

114P - A Phase 1B Study of Anti-Dll4 (DELTA-LIKE LIGAND 4) Antibody Demcizumab (DEM) with Pemetrexed (PEM) and Carboplatin (CARBO) in Patients with 1St-Line Non-Squamous Nsclc

Abstract 2993: Dll4 inhibition plus aflibercept markedly reduces ovarian tumor burden and ascites

Abstract Purpose: To determine the effects of Dll4 blockade with and without aflibercept on ovarian tumor burden and ascites in preclinical models. Methods: Using Dll4-Fc and anti-Dll4 antibodies, we evaluated the biological effects of Dll4 inhibition combined with aflibercept in vivo (orthotopic mouse models of ovarian cancer). Reverse phase protein array (RPPA) analysis was used to identify potential biomarkers of treatment response. Results: To address the biological significance of Dll4 expression in tumor cells versus endothelial cells, we used human and mouse anti-Dll4 antibodies in vivo. In the A2780 model, treatment with mouse (REGN1035) or human (REGN421) anti-Dll4 antibodies reduced tumor weight by 61.5% and 82.4%, respectively, compared to the controls (P < 0.05 for both). Aflibercept alone reduced tumor weight by 90% (p < 0.05). The combinations of REGN1035 plus aflibercept, and REGN421 plus aflibercept resulted in the greatest inhibition of tumor growth, reducing respective tumor weight by 95.8% and 93.9%, compared to the controls (P < 0.05). The anti-tumor effects were related to decreased angiogenesis and increased apoptosis. RPPA analysis revealed that caspase3 and GATA3 were significantly increased; cyclin D1, Bcl-2 and pS6-s240_s244 were decreased in response to Dll4 Inhibition plus aflibercept. Among these, GATA3, a transcription factor for E-cadherin, was significantly induced by Dll4 Inhibition plus aflibercept, resulting in the up-regulation of E-cadherin expression in human cancer cells. Furthermore, GATA3 and E-cadherin expression might be useful as potential biomarkers of response. Conclusions: Dual targeting of Dll4 and VEGF shows promise for inhibiting ovarian tumor growth and may have important clinical implications. Citation Format: Jie Huang, Wei Hu, Heather J. Dalton, Justin Bottsford-Miller, Robert L. Coleman, Robert B. Jaffe, Anil K. Sood. Dll4 inhibition plus aflibercept markedly reduces ovarian tumor burden and ascites. [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 2993. doi:10.1158/1538-7445.AM2014-2993

87IN - Cardiac Toxicity of Novel Agents

ABSTRACT With the emergence of novel molecularly targeted agents and immunotherapeutics, cardiac and cardiovascular toxicities may occur as a consequence of on-target or off-target effects, including ventricular dysfunction, hypertension and QTc prolongation. Drug-induced ventricular dysfunction associated with anticancer agents occurs via distinct mechanisms. Cytotoxic chemotherapy agents such as anthracyclines can cause type I injury, which is characterized by myocyte cell death and is typically cumulative dose-related and permanent. In contrast, cardiac toxicity induced by molecularly targeted agents such as trastuzumab is classified as type II injury, and is due to myocyte dysfunction without cell death. As such, type II cardiac injuries are generally not cumulative dose-related and are predominantly reversible. Amongst the newer molecularly targeted agents, ventricular dysfunction has been reported with pertuzumab, trastuzumab-DM1, angiogenesis inhibitors including multikinase inhibitors and anti-DLL4 antibodies, ABL inhibitors, and MEK inhibitors. Immune-mediated and autoimmune myocarditis has been reported with immune checkpoint inhibitors such as anti-CTLA4 antibodies. Hypertension has been commonly reported with angiogenesis inhibitors and is also induced by MEK inhibitors in some patients. Prolongation of the QTc interval has been reported with HDAC inhibitors, ABL inhibitors, MET inhibitors and angiogenesis inhibitors. The pathophysiology, diagnosis and management of these cardiac and cardiovascular toxicities of novel anticancer agents will be discussed. Disclosure: L.L. Siu: Clinical trial research support from: Novartis, GSK, Bristol Myers Squibb, Pfizer, Roche/Genentech, Karyopharm, Regeneron, AstraZeneca, Boehringer-Ingelheim.

A Phase 1B Study of the Anti-Cancer Stem Cell Agent Demcizumab (Dem), Pemetrexed (Pem) & Carboplatin (Carbo) in Pts with 1St Line Non-Squamous Nsclc

ABSTRACT Aim: Delta-like ligand 4 (DLL4) activates the Notch pathway and is important for cancer stem cell (CSC) survival. DEM is a humanized IgG2 anti-DLL4 antibody that has been shown to inhibit tumor growth, decrease CSC frequency & cause dysfunctional sprouting of new vessels resulting in an antiangiogenic effect in human tumor xenograft models. Methods: Pts received DEM (2.5 or 5 mg/kg), PEM 500 mg/m2 & CARBO (AUC = 6) every 3 wks X 6 cycles followed by maintenance DEM (cohorts 1-4) or truncated DEM (5 or 7.5 mg/kg), PEM 500 mg/m2 & CARBO (AUC = 6) every 3 wks X 4 cycles followed by maintenance PEM (cohorts 5 & 6). The objectives were to determine the MTD, safety, efficacy, immunogenicity, pharmacokinetics & biomarkers of Notch signaling. Results: Thirty-nine pts were enrolled; 6 received 2.5 mg/kg, 20 received 5 mg/kg, 6 received 7.5 mg/kg of truncated DEM & 7 received 5 mg/kg of truncated DEM. Related AEs in > 20% of pts were: nausea (49%), fatigue (44%), hypertension (41%), vomiting (31%), edema (26%), neutropenia (26%), & increased B-type natriuretic peptide (BNP) (23%). Increased BNP values are an early indicator of the cardiac effects of DEM & mildly elevated values are being used to initiate cardioprotective therapy with an ACE inhibitor or carvedilol. Two pts receiving 5 mg/kg developed reversible pulmonary hypertension & heart failure on days 167 & 183, respectively. As a result, DEM treatment was limited to 63 days in cohorts 5 & 6. One of 32 (3%) evaluable pts had a RECIST CR, 13 (41%) had a PR and 14 had SD. The Kaplan Meier estimated median progression free survivals for the 2.5, 5, truncated 5 & truncated 7.5 mg/kg pts were 4.3, 5.3, not yet reached & 4.4 months, respectively. Five pts who discontinued the study for a reason other than progression (3 continued to receive CARBO & PEM off-study) were progression-free through Days 223 + , 243 + , 457 + , 497 + , 680+ and a sixth pt (who continued to receive CARBO & PEM off-study) progressed at Day 850. Conclusions: This therapy was generally well tolerated with nausea, fatigue & hypertension being the most common drug related toxicities. Encouraging early clinical activity has been observed. Additional data with truncated DEM will be presented. Disclosure: R. Stagg: I am an employee of OncoMed and I own stock in the company; J. Dupont: I work for OncoMed and own stock in the company. All other authors have declared no conflicts of interest.

616PD - A Ph 1B Study of the Anti-Cancer Stem Cell Agent Demcizumab (Dem) & Gemcitabine (Gem) +/- Paclitaxel Protein Bound Particles (Nab-Paclitaxel) in Pts with Pancreatic Cancer

ABSTRACT Aim: Delta-like ligand 4 (DLL4) is a ligand that activates the Notch pathway. DEM is a humanized IgG2 anti-DLL4 antibody that inhibits tumor growth & decreases cancer stem cell frequency in minimally passaged human xenograft models. In addition, DEM has an antiangiogenic effect & synergistic activity when combined with GEM & nab-paclitaxel in human pancreatic tumor-derived xenograft models. Methods: Pts with 1st line pancreatic cancer were enrolled. Pts in cohorts 1-3 received DEM (2.5 every 2 or 4 wks or 5 mg/kg every 4 wks including 3 truncated pts) & GEM 1000 mg/m2 7 of 8 wks, then 3 of 4 wks. Pts in cohorts 4 & 5 received truncated DEM (2.5 or 5 mg/kg every 2 wks through Day 70) & nab-paclitaxel 125 mg/m2 + gemcitabine 1000 mg/m2 3 of 4 weeks. The primary objective was to determine the MTD. Other objectives were safety, efficacy, immunogenicity, PK & biomarkers. Results: Thirty-eight pts were enrolled; 8, 8, 8, 6 & 8 pts received 2.5 mg/kg every 2 wks, 2.5 mg/kg every 4 wks, 5 mg/kg every 4 wks, 2.5 mg/kg every 2 weeks (truncated) & 5 mg/kg every 2 weeks (truncated), respectively. Related AEs in > 20% of pts were nausea (37%), fatigue (34%), nausea, vomiting (32%), decreased appetite (24%) & hypertension (21%). Hypertension was managed with anti-hypertensives. Increased BNP is an early indicator of the cardiac effects of DEM & mildly elevated values are used to initiate cardioprotective therapy with an ACE inhibitor or carvedilol. One pt who received 5 mg/kg continuously developed reversible pulmonary hypertension & heart failure on day 143. As a result, DEM was limited to 70 days in cohorts 4 & 5. In cohorts 1-3, 4 of 16 (25%) pts had a partial response (PR) & 7 had stable disease (SD). In cohorts 4 & 5, 6 of 14 (43%) pts had a PR & 6 had SD. The median PFS for 2.5 & 5 mg/kg every 4 wks and 2.5 mg/kg, 2.5 mg/kg (truncated) & 5 mg/kg (truncated) every 2 wks were 1.7, 7, 3.4, not reached and 3.5 mos., respectively. The 3 truncated pts in cohort 3 had PFS of 5.4, 7 and 9.1 mos. Conclusions: This therapy was generally well tolerated with fatigue, nausea & vomiting being the most common related AEs. Encouraging early clinical activity was observed. Additional data with truncated DEM will be presented. Disclosure: R. Stagg and J. Dupont: I am an employee of OncoMed and own stock in the company. All other authors have declared no conflicts of interest.

A phase 1b study of the anticancer stem cell agent demcizumab (DEM), pemetrexed (PEM), and carboplatin (CARBO) in pts with first-line nonsquamous NSCLC.

2544 Background: Delta-like ligand 4 (DLL4) activates the Notch pathway and is important for cancer stem cell (CSC) survival. DEM is a humanized IgG2 anti-DLL4 antibody that has been shown to inhib...

Abstract A49: Anti-DLL4 antibodies inhibit cancer stem cells in small cell lung cancer.

Abstract Small cell lung cancer (SCLC) is a very aggressive lung cancer with features suggesting enrichment in cancer stem cells (CSCs). Delta-like ligand 4 (DLL4) is a membrane bound ligand for Notch receptors critical for functional angiogenesis. Blocking DLL4 signaling increases the density of nonfunctional blood vessels and hypoxia of tumors, and thereby inhibits growth of tumor xenografts in mice. In addition, growing evidence implicates DLL4 Notch signaling pathway in the maintenance of CSCs. Here we investigated the anti-CSC activity of anti-DLL4 mAbs using in vitro and in vivo models of SCLC. Biochemical and flow cytometry analyses revealed that multiple SCLC cell lines express DLL4, and notably, SCLC spheres cultured under CSC-enriching conditions express higher levels of DLL4. Prior to determining the ability of anti-DLL4 mAb in inhibiting CSC in vivo, we first characterized the phenotype of CSCs in the SCLC cell line NCI-H69. NCI-H69 cells enriched for high CD133 expression were more tumorigenic and expressed higher levels of Nanog, Oct 3/4, and EZH2, which are genes crucial for maintenance of CSCs, than cells with low or negative levels of CD133. Moreover, RNA level of DLL4 was found to be three fold higher in CD133 high cells compared to CD133 low cells, suggesting that expression of DLL4 correlates with the CSC phenotype. In vivo, an anti-DLL4 antibody leads to inhibition of NCI-H69 tumor growth when the antibody is administered as a single agent, or in combination with cisplatin+etoposide or topotecan, chemotherapy agents commonly used in treatment of SCLC. To determine if blockade of DLL4 inhibits CSCs in vivo, NCI-H69 tumor xenografts treated with anti-DLL4 mAb were analyzed by flow cytometry. A subset of dissociated tumor cells expressed CD133 and DLL4, and a reduction of these populations of cells was observed in the anti-DLL4 antibody treated groups. In summary, these studies highlight that, in addition to vascular expression, (1) DLL4 is frequently expressed in SCLC cells, (2) DLL4 expression correlates with a CSC phenotype, and (3) that DLL4 blockade using an anti-DLL4 mAb results in inhibition of CSCs. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A49. Citation Format: Patrick Strout, Martin Korade, Ching Ching Leow, Ivan Inigo, Suneetha Thomas, Elaine Hurt, Jon Chesebrough, Adeela Kamal, Song Cho. Anti-DLL4 antibodies inhibit cancer stem cells in small cell lung cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A49.

Abstract B78: A Phase Ib study of demcizumab (DEM, anti-DLL4) with gemcitabine (GEM) in patients with first line locally advanced or metastatic pancreatic cancer.

Abstract Background: Delta-like ligand 4 (DLL4) is a ligand that activates the Notch pathway which is important for cancer stem cell (CSC) survival. DEM is a humanized IgG2 anti-DLL4 antibody that has been shown to inhibit tumor growth and decrease CSC frequency in minimally passaged human xenograft models. In addition, inhibition of DLL4 has also been shown in preclinical studies to cause dysfunctional sprouting of new vessels resulting in an antiangiogenic effect. DEM also showed synergistic activity when combined with GEM in human pancreatic tumor-derived xenograft models. Material and Methods: Patients with first line stage III or IV pancreatic cancer received DEM (2.5 every 2 or 4 wks or 5 mg/kg every 4 wks) and GEM 1000 mg/m2 7 of the 1st 8 wks and then 3 of every 4 wks until disease progression. The primary objective was to determine the maximum tolerated dose of DEM. Other objectives included: safety, efficacy, immunogenicity, pharmacokinetic, and biomarkers of Notch signaling and CSCs. Results: Twenty four patients were enrolled; 8 pts received 2.5 mg/kg every 2 wks, 8 received 2.5 mg/kg every 4 wks and 8 received 5 mg/kg every 4 wks of DEM. The median age was 65.5 yrs. Three (12.5%) and 21 (87.5%) patients had stage III and IV disease, respectively. Seven, 16 and 1 patients were ECOG performance status 0, 1, and 2, respectively. Related adverse events (all grades) in ≥10% of patients included: fatigue (29%), hypertension (29%), vomiting (29%), nausea (25%), thrombocytopenia (21%), decreased appetite (21%), increased B-type natriuretic peptide (BNP) (13%), anemia (13%), peripheral edema (13%), pulmonary hypertension (13%), dizziness (13%) and rash (13%). The hypertension was successfully managed with oral anti-hypertensives. Increased BNP values appear to be an early indicator of the cardiac effects of DEM and mildly elevated values are being used to initiate cardioprotective therapy with an ACE inhibitor or carvedilol. One patient who received 5 mg/kg developed reversible pulmonary hypertension and heart failure on study day 143. As a result, the duration of DEM will be limited to 70 days in subsequent cohorts and paclitaxel protein-bound particles will also be added to the regimen. Four of 16 (25%) evaluable patients had a RECIST partial response and 7 had stable disease. The median progression free survival for the 5 mg/kg cohort was 5.9 months. The pharmacokinetic and immunogenicity samples are being analyzed and these data will be presented. Conclusion: DEM plus GEM was generally well tolerated with fatigue, hypertension and vomiting being the most common drug related adverse events. The duration of demcizumab therapy is being limited to 70 days in subsequent cohorts due to cardiopulmonary toxicity which was observed following more prolonged administration. Encouraging early clinical activity has been observed. Subsequent cohorts will include paclitaxel protein-bound particles. Enrollment is ongoing and updated results will be presented. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B78. Citation Format: Antonio Cubillo, Michael Jameson, Enrique Grande, Francis Parnis, Peter Grimison, Prasad Cooray, Mark Jeffery, Robert Stagg, Jakob Dupont, Niall Tebbutt. A Phase Ib study of demcizumab (DEM, anti-DLL4) with gemcitabine (GEM) in patients with first line locally advanced or metastatic pancreatic cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B78.

Abstract A71: A Phase Ib study of demcizumab (DEM, anti-DLL4) plus pemetrexed and carboplatin in patients with first line stage IIIb/IV non-squamous non-small cell lung cancer.

Abstract Background: Delta-like ligand 4 (DLL4) is a ligand that activates the Notch pathway which is important for cancer stem cell (CSC) survival. DEM is a humanized IgG2 anti-DLL4 antibody that has been shown to inhibit tumor growth and decrease CSC frequency in minimally passaged human xenograft models. In addition, inhibition of DLL4 has also been shown in preclinical studies to cause dysfunctional sprouting of new vessels resulting in an antiangiogenic effect. Material and Methods: Patients received DEM (2.5, 5, or 7.5 mg/kg), pemetrexed 500 mg/m2, and carboplatin (AUC = 6) every 3 weeks followed by maintenance DEM (first 4 cohorts) or pemetrexed (7.5 mg/kg cohort) every 3 weeks until disease progression. Folic acid, vitamin B12 and dexamethasone were administered as pemetrexed pre-medication. The primary study objective was to determine the maximum tolerated dose of DEM. Other objectives included: safety, efficacy, immunogenicity, pharmacokinetic and biomarkers of Notch signaling. Results: Thirty patients have been enrolled; 6 received 2.5 mg/kg, 20 received 5 mg/kg and 4 received 7.5 mg/kg of DEM once every 3 weeks. The median age was 63 years and 90% had stage IV disease. Related adverse events (all grades) in ≥10% of pts included: nausea (53%), fatigue (50%), hypertension (37%), vomiting (33%), neutropenia (27%), increased B-type natriuretic peptide (BNP) (23%), anemia (20%), peripheral edema (20%), increased ALT (20%), increased AST (17%), dyspnea, (17%), diarrhea (17%), decreased appetite (17%), pulmonary hypertension (13%), dysgeusia (13%), thrombocytopenia (13%), constipation (10%), and rash (10%). The hypertension was managed with oral anti-hypertensives. Increased BNP values appear to be an early indicator of the cardiac effects of DEM and mildly elevated values are being used to initiate cardioprotective therapy with an ACE inhibitor or carvedilol. Two patients receiving 5 mg/kg developed reversible pulmonary hypertension and heart failure on days 167 and 183, respectively. As a result, the duration of DEM was limited to 63 days in the 7.5 mg/kg dose cohort. The pharmacokinetics and immunogenicity specimens are being analyzed and these data will be presented. Nine of the 23 (39%) evaluable patients had a RECIST partial response and 11 had stable disease. The median progression free survival for the 5 mg/kg cohort was 5.3 months. Conclusion: DEM, pemetrexed and carboplatin was generally well tolerated with nausea, fatigue and hypertension being the most common drug related toxicities. The duration of demcizumab therapy is being limited to 63 days in subsequent cohorts due to cardiopulmonary toxicity which was observed following more prolonged administration. Encouraging early clinical activity has been observed. Enrollment is ongoing and updated results will be presented. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A71. Citation Format: Mark McKeage, Dusan Kotasek, Ben Markman, Michael Millward, Manuel Hildalgo, Michael Jameson, Dean Harris, Robert Stagg, Jakob Dupont, Brett Hughes. A Phase Ib study of demcizumab (DEM, anti-DLL4) plus pemetrexed and carboplatin in patients with first line stage IIIb/IV non-squamous non-small cell lung cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A71.

Abstract 4330: In vivo evaluation of anti-tumor activity by an anti-VEGF and anti-DLL4 bispecific antibody in a humanized model of skin graft.

Abstract Both Notch/Delta-like ligand 4 (DLL4) and vascular endothelial growth factor (VEGF) pathways play a critical role in angiogenesis and tumor growth. Due to differential regulatory effects of VEGF and DLL4 on the vasculature, blockage of DLL4 or VEGF inhibits tumor growth by distinct mechanisms: anti-DLL4 treatment induces an abnormal increase of poorly perfused blood vessels, which results in a nonproductive angiogenesis unable to support tumor growth, whereas the anti-VEGF therapy significantly decreases vasculature reducing the blood supply to tumors. In our study, we have developed a bispecific monoclonal antibody that targets both human DLL4 (hDLL4) and human VEGF (hVEGF). In vitro, this antibody demonstrated nanomolar affinity to hVEGF and hDLL4, and reduced HUVEC proliferation induced by VEGF (EC50 0.86 ug/ml). To test the activity of this bispecific antibody in vivo, we developed a human skin graft model in NOD/SCID mice, and implanted human tumor specimen-derived colon cancer cells intradermally into these skin transplants. The tumor model was selected based on its sensitivity to both the anti-human DLL4 antibody, OMP-21M18, and to the human VEGF inhibitor bevacizumab. The skin graft model provides a suitable human microenvironment for evaluating anti-tumor efficacy and anti-angiogenesis of the bispecific antibody directed against the human component of DLL4 and VEGF and allows a comparison to OMP-21M18 and also to bevacizumab. Each of these treatments was administered to mice intraperitoneally at a dose of 25 mg/Kg weekly. The bispecific antibody caused a significant inhibition of tumor growth (87% TGI) compared to control antibody (p=0.00001), and this effect was superior to either OMP-21M18 (45% TGI) or bevacizumab (70%TGI). The inhibition of tumor growth by the bispecific antibody was consistently associated with increased blood vessels, up-regulated VEGFA and VEGFR2, and enhanced hypoxia and these effects were more pronounced compared to OMP-21M18. As expected, in this model bevacizumab caused a significant decrease of blood vessels, down-regulated VEGFR2, and increased hypoxia. In separate experiments with mice bearing subcutaneous human colon tumors, the bispecific antibody delayed tumor recurrence following termination of chemotherapy and impacted tumorigenicity by decreasing the frequency of tumor initiating cells. These results suggest that our bispecific anti-DLL4 and anti-VEGF antibody is a potential candidate in the treatment of tumors driven by both VEGF and Notch/DLL4 signaling pathways. Citation Format: Lucia Beviglia, Pete Yeung, Wang-Ching Yen, Belinda Cancilla, Sato Aaron, Chris Bond, Janak Raval, Fumiko Axelrod, Cecile Chartier, Shirley Ma, Austin Gurney, John Lewicki, Ann M. Kapoun, Timothy Hoey. In vivo evaluation of anti-tumor activity by an anti-VEGF and anti-DLL4 bispecific antibody in a humanized model of skin graft. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4330. doi:10.1158/1538-7445.AM2013-4330

Abstract 5098: A mouse DLL4 cross-reactive variant of MEDI0639 disrupts functional vessel formation and inhibits tumor growth in preclinical models.

Abstract Delta-like ligand 4 (DLL4) is a membrane bound ligand for Notch receptors essential for functional vessel formation during development and angiogenesis. We have shown previously that MEDI0639, a human anti-DLL4 antibody, has potent in vitro and in vivo activity in blocking DLL4-Notch interaction. However, because MEDI0639 has low binding affinity to mouse DLL4, to enable in vivo pharmacology studies using xenograft tumor models in mice, MEDI0639 was engineered to bind more strongly to mouse DLL4. The resulting affinity-optimized variant antibody (anti-mDLL4 mAb) bound with high affinity to both human and mouse DLL4 and maintained binding specificity to DLL4. In a number of human cancer xenograft models in nude mice, the MEDI0639 variant antibody markedly inhibited the growth of tumors. qRT-PCR analysis using the Fluidigm platform showed decreases in mouse genes downstream of the Notch signaling pathway at efficacious doses, indicating on-target antibody effect on tumor vasculature. In addition, IHC and imaging analysis of xenograft tumors from the anti-DLL4 mAb dosed animals showed a dose-dependent increase in microvessel density and decrease in tumor perfusion compared to the control groups. In summary, we describe here the generation of mouse and human DLL4 cross-reactive antibody and the utilization of this antibody in demonstrating a positive correlation between the anticipated mechanism of action of DLL4 blockade on vasculature and inhibition of tumor growth. Citation Format: Song H. Cho, David W. Jenkins, Patrick Strout, Martin Korade, Haihong Zhong, Ching Ching Leow, Shannon Breen, Jon Chesebrough, Nicholas Holoweckyj, Ivan Inigo, Gennady Gololobov, Ping Tsui, Kimberly Cook, Melissa Damschroder, Meggan Czapiga, Philip Brohawn, Jiaqi Huang, Sally-Ann Ricketts, Juliana Maynard, Adeela Kamal. A mouse DLL4 cross-reactive variant of MEDI0639 disrupts functional vessel formation and inhibits tumor growth in preclinical models. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5098. doi:10.1158/1538-7445.AM2013-5098

Inhibition of delta-like ligand 4 decreases Th1/Th17 response in a mouse model of multiple sclerosis

Notch is a family of receptors involved in the differentiation of several tissues, including the central nervous system and the immune system. One of the Notch ligands, delta-like 4 (Dll4), has been implicated in the differentiation of Th1 cells and the development of Th17 responses, which are involved in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis. Our results show that a single administration of an anti-Dll4 antibody is not enough to avoid the development of EAE or to ameliorate the already established clinical signs, despite the treatment reduces the proliferative T cell responses and decreases Th1/Th17 immune responses.

High DLL4 expression in tumour-associated vessels predicts for favorable radiotherapy outcome in locally advanced squamous cell head-neck cancer (HNSCC)

Expression of the DLL4 (a notch pathway ligand) by tumor-associated endothelium is a postulated marker of vascular maturity and functionality. As vascular functionality is an important parameter defining chemotherapy and oxygen intra-tumoral distribution, we investigated the role of DLL4 expression in tumour vasculature in the efficacy of radio-chemotherapy for HNSCC patients. Sixty-five biopsy specimens from HNSCC patients with inoperable disease were immunohistochemically examined using anti-CD31 (pan-endothelial cell marker) and anti-DLL4 antibodies and the vascular density (VD) was recorded. Patients were treated with platinum based hypofractionated accelerated conformal radiotherapy. The median follow-up period was 24 months (4-80 months). Using the 33rd and 66th percentiles cases were grouped in three categories of low, medium and high CD31+ or DLL4+ VD. The percentage of vessels expressing DLL4 (DLL4-ratio) ranged from 17 to 100 % (mean 71 %), showing substantial variation among cases. In accordance with previous published studies, a biphasic pattern of association of CD31+ VD with poor outcome was noted. Cases with a medium VD had a significantly better local relapse free survival (LRFS) compared to cases of high VD (p = 0.0005, HR 0.15) and of low VD (p = 0.02, HR 0.28). High DLL4/CD31 ratio defined improved LRFS in both these subgroups of poor prognosis. The expression of DLL4 is associated with reduced radio-resistance, presumably by reducing hypoxia and improving chemotherapy accessibility. Using the combination of CD31 and DLL4 staining, a classification is suggested so that HNSCCs are categorized in sub-groups to be targeted by different anti-angiogenic and hypoxia targeting agents.

Notch ligand Delta-like 4 blockade attenuates atherosclerosis and metabolic disorders

Atherosclerosis and insulin resistance are major components of the cardiometabolic syndrome, a global health threat associated with a systemic inflammatory state. Notch signaling regulates tissue development and participates in innate and adaptive immunity in adults. The role of Notch signaling in cardiometabolic inflammation, however, remains obscure. We noted that a high-fat, high-cholesterol diet increased expression of the Notch ligand Delta-like 4 (Dll4) in atheromata and fat tissue in LDL-receptor-deficient mice. Blockade of Dll4-Notch signaling using neutralizing anti-Dll4 antibody attenuated the development of atherosclerosis, diminished plaque calcification, improved insulin resistance, and decreased fat accumulation. These changes were accompanied by decreased macrophage accumulation, diminished expression of monocyte chemoattractant protein-1 (MCP-1), and lower levels of nuclear factor-κB (NF-κB) activation. In vitro cell culture experiments revealed that Dll4-mediated Notch signaling increases MCP-1 expression via NF-κB, providing a possible mechanism for in vivo effects. Furthermore, Dll4 skewed macrophages toward a proinflammatory phenotype ("M1"). These results suggest that Dll4-Notch signaling plays a central role in the shared mechanism for the pathogenesis of cardiometabolic disorders.