EGFL7 reduces CNS inflammation in mouse.

Extracellular matrix (ECM) proteins secreted by blood-brain barrier (BBB) endothelial cells (ECs) are implicated in cell trafficking. We discovered that the expression of ECM epidermal growth factor-like protein 7 (EGFL7) is increased in the CNS vasculature of patients with multiple sclerosis (MS), and in mice with experimental autoimmune encephalomyelitis (EAE). Perivascular CD4 T lymphocytes colocalize with ECM-bound EGFL7 in MS lesions. Human and mouse activated T cells upregulate EGFL7 ligand αvß3 integrin and can adhere to EGFL7 through integrin αvß3. EGFL7-knockout (KO) mice show earlier onset of EAE and increased brain and spinal cord parenchymal infiltration of T lymphocytes. Importantly, EC-restricted EGFL7-KO is associated with a similar EAE worsening. Finally, treatment with recombinant EGFL7 improves EAE, reduces MCAM expression, and tightens the BBB in mouse. Our data demonstrate that EGFL7 can limit CNS immune infiltration and may represent a novel therapeutic avenue in MS.

Randomized Phase II Trial of Parsatuzumab (Anti-EGFL7) or Placebo in Combination with FOLFOX and Bevacizumab for First-Line Metastatic Colorectal Cancer.

LESSONS LEARNED: These negative phase II results for parsatuzumab highlight the challenges of developing an agent intended to enhance the efficacy of vascular endothelial growth factor inhibition without the benefit of validated pharmacodynamic biomarkers or strong predictive biomarker hypotheses.Any further clinical development of anti-EGFL7 is likely to require new mechanistic insights and biomarker development for antiangiogenic agents. BACKGROUND: EGFL7 (epidermal growth factor-like domain 7) is a tumor-enriched vascular extracellular matrix protein that supports endothelial cell survival. This phase II trial evaluated the efficacy of parsatuzumab (also known as MEGF0444A), a humanized anti-EGFL7 IgG1 monoclonal antibody, in combination with modified FOLFOX6 (mFOLFOX6) (folinic acid, 5-fluorouracil, and oxaliplatin) bevacizumab in patients with previously untreated metastatic colorectal cancer (mCRC). METHODS: One-hundred twenty-seven patients were randomly assigned to parsatuzumab, 400 mg, or placebo, in combination with mFOLFOX6 plus bevacizumab, 5 mg/kg. Treatment cycles were repeated every 2 weeks until disease progression or unacceptable toxicity for a maximum of 24 months, with the exception of oxaliplatin, which was administered for up to 8 cycles. RESULTS: The progression-free survival (PFS) hazard ratio was 1.17 (95% confidence interval [CI], 0.71-1.93; p = .548). The median PFS was 12 months for the experimental arm versus 11.9 months for the control arm. The hazard ratio for overall survival was 0.97 (95% CI, 0.46-2.1; p = .943). The overall response rate was 59% in the parsatuzumab arm and 64% in the placebo arm. The adverse event profile was similar in both arms. CONCLUSIONS: There was no evidence of efficacy for the addition of parsatuzumab to the combination of bevacizumab and chemotherapy for first-line mCRC. The Oncologist 2017;22:375-e30.

Real-time immuno-polymerase chain reaction in a 384-well format: detection of vascular endothelial growth factor and epidermal growth factor-like domain 7.

Immuno-polymerase chain reaction (immuno-PCR) combines the specificity of antibodies with the amplification power of PCR to detect low levels of proteins. Here, we describe the development of a 384-well immuno-PCR method that uses streptavidin coated on a PCR plate to capture complexes of biotinylated capture antibody, antigen, and DNA-labeled detection antibody. Unbound molecules are removed by a wash step using a standard plate washer. Antibody-DNA molecules in bound complexes are then detected directly on the plate using real-time PCR. Circulating human vascular endothelial growth factor concentrations measured by this method correlated with measurements obtained from enzyme-linked immunosorbent assay (ELISA). Using this method, we developed an assay for human epidermal growth factor-like domain 7 (EGFL7), an extracellular matrix-bound angiogenic factor. EGFL7 is expressed at a higher level in certain cancers, although endogenous EGFL7 concentrations have not been reported. Our 384-well EGFL7 immuno-PCR assay can detect 0.51pM EGFL7 in plasma, approximately 16-fold more sensitive than the ELISA, utilizing the same antibodies. This assay detected EGFL7 in lysates of non-small-cell lung cancer and hepatocellular carcinoma cell lines and also hepatocellular carcinoma, breast cancer, and ovarian cancer tissues. This 384-well immuno-PCR method can be used to develop high-throughput biomarker assays.

Antibodies to endothelial cell growth factor and obliterative microvascular lesions in the synovium of patients with antibiotic-refractory lyme arthritis.

OBJECTIVE: Endothelial cell growth factor (ECGF) was recently identified as the first autoantigen known to be a target of T cell and B cell responses in ~20% of patients with antibiotic-refractory Lyme arthritis. The goal of the current study was to look for a pathologic correlate between ECGF autoantibody responses and histologic findings in synovial tissue. METHODS: Synovial tissue was examined from 14 patients with antibiotic-refractory Lyme arthritis and 6 patients with other forms of chronic inflammatory arthritis, primarily rheumatoid arthritis. The tissue sections were subjected to chemical and immunostaining, and IgG antibody responses to ECGF were determined by enzyme-linked immunosorbent assay (ELISA). Each finding was ranked for statistical analysis. RESULTS: In each disease, synovial tissue showed synovial hypertrophy, vascular proliferation, immune cell infiltrates, and fibrosis. However, among the 14 patients with antibiotic-refractory arthritis, 8 (57%) had obliterative microvascular lesions in the tissue, compared with none of the 6 patients with other forms of chronic inflammatory arthritis (P = 0.04). Among the patients with Lyme arthritis, 5 (36%) had autoantibody responses to ECGF, and all 5 had obliterative lesions, as compared with only 3 of 9 patients who lacked ECGF antibody responses (P = 0.009). Moreover, the magnitude of ECGF antibody responses correlated directly with the extent of obliterative lesions (P = 0.02) and with greater vascularity in the tissue (P = 0.05). CONCLUSION: The correlations of ECGF autoantibody reactivity with obliterative microvascular lesions imply that these autoantibodies may be involved in the obliterative process, suggesting that anti-ECGF antibodies have specific pathologic consequences in the synovial tissue of patients with antibiotic-refractory Lyme arthritis.

Anti-EGFL7 antibodies enhance stress-induced endothelial cell death and anti-VEGF efficacy.

Many oncology drugs are administered at their maximally tolerated dose without the knowledge of their optimal efficacious dose range. In this study, we describe a multifaceted approach that integrated preclinical and clinical data to identify the optimal dose for an antiangiogenesis agent, anti-EGFL7. EGFL7 is an extracellular matrix-associated protein expressed in activated endothelium. Recombinant EGFL7 protein supported EC adhesion and protected ECs from stress-induced apoptosis. Anti-EGFL7 antibodies inhibited both of these key processes and augmented anti-VEGF-mediated vascular damage in various murine tumor models. In a genetically engineered mouse model of advanced non-small cell lung cancer, we found that anti-EGFL7 enhanced both the progression-free and overall survival benefits derived from anti-VEGF therapy in a dose-dependent manner. In addition, we identified a circulating progenitor cell type that was regulated by EGFL7 and evaluated the response of these cells to anti-EGFL7 treatment in both tumor-bearing mice and cancer patients from a phase I clinical trial. Importantly, these preclinical efficacy and clinical biomarker results enabled rational selection of the anti-EGFL7 dose currently being tested in phase II clinical trials.

A novel human autoantigen, endothelial cell growth factor, is a target of T and B cell responses in patients with Lyme disease.

OBJECTIVE: Autoantigen presentation by HLA-DR molecules is thought to be a central component of many autoimmune diseases, but identifying disease-relevant autoantigens has been a difficult challenge. In this study we aimed to identify autoantigens in patients with antibiotic-refractory Lyme arthritis, in which infection-induced autoimmunity is thought to play an important role. METHODS: Using tandem mass spectrometry, naturally presented HLA-DR self peptides from a patient's synovium were identified, synthesized, and reacted with his peripheral blood mononuclear cells (PBMCs). Immunoreactive peptides and their source proteins were then tested for T and B cell responses using large numbers of patient cells or sera. RESULTS: Of 120 HLA-DR-presented self peptides identified from one patient, one peptide derived from endothelial cell growth factor (ECGF) caused his PBMCs to proliferate. T and B cell responses to ECGF occurred systemically in ∼10-30% of patients with early or late manifestations of Lyme disease, primarily in those with refractory arthritis-associated HLA-DR alleles, such as DRB1*0101 and 0401. Compared with patients with antibiotic-responsive arthritis, those with antibiotic-refractory arthritis had significantly higher concentrations of ECGF in synovial fluid (P<0.0001) and more often had ECGF antibody reactivity. Among non-antibiotic-treated historical patients who developed arthritis, 26% had ECGF reactivity, which often developed before the onset of arthritis and was associated with significantly longer courses of arthritis. CONCLUSION: T and B cell responses to ECGF occur in a subset of patients with Lyme disease, particularly in those with antibiotic-refractory arthritis, providing the first direct evidence of autoimmune T and B cell responses in this illness.

Human anti-EGFL7 recombinant full-length antibodies selected from a mammalian cell-based antibody display library.

Epidermal growth factor-like domain 7 (EGFL7) has been implicated in promoting solid tumor growth and metastasis via stimulating tumor-associated angiogenesis. The advent of antibody display technology (phage, bacteria, and yeast) led to an enormous revival in the use of antibodies as diagnostic and therapeutic tools for fighting cancer. However, problems with protein folding, posttranslational modification, and codon usage still limit the number of improved antibodies that can be obtained. We describe here the isolation of an EGFL7-specific antibody from a mammalian cell-based full-length antibody display library generated from peripheral blood mononuclear cells of patients with hepatocellular carcinoma. Using a novel vector, contained glycosylphosphatidylinositol anchor and restriction enzyme sites NheI and ClaI, antibody libraries are displayed as whole IgG molecules on the cell surface and screened for specific antigen binding by a combination of magnetic beads and measured by cell ELISA. Anti-EGFL7 antibody was successfully isolated from the library. The mammalian cell-based full-length antibody display library is a great potential application for rapid identification and cloning of human mAbs of targeting hepatocellular carcinoma.

Egfl7 promotes tumor escape from immunity by repressing endothelial cell activation.

Downregulating the leukocyte adhesion molecules expressed by endothelial cells that line tumor blood vessels can limit the entry of immune effector cells into the tumor mass, thereby contributing to tumoral immune escape. Egfl7 (also known as VE-statin) is a secreted protein specifically expressed by endothelial cells in normal tissues and by cancer cells in various human tumors. High levels of Egfl7 correlate with higher tumor grade and poorer prognosis. Here we show that expression of Egfl7 in breast and lung carcinoma cells accelerates tumor growth and metastasis in immunocompetent mice but not in immunodeficient mice. Tumors expressing Egfl7 were infiltrated relatively poorly by immune cells and were characterized by reduced levels of immunostimulatory cytokines [IFN-γ, interleukin-12 (IL-12)] and fewer endothelial adhesion molecules [intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1)]. In vitro studies revealed that Egfl7 inhibited the expression of leukocyte adhesion molecules by endothelial cells, preventing lymphocyte adhesion. In contrast, Egfl7 did not exert any effects on immune cell activation. Human breast cancer lesions expressing high levels of Egfl7 also expressed less ICAM-1 and VCAM-1 in their blood vessels, also indicating an inverse correlation between expression levels of Egfl7 and IFN-γ. Thus, Egfl7 expression in tumors promotes tumor progression by reducing the expression of endothelial molecules that mediate immune cell infiltration. Our findings highlight a novel mechanism through which tumors escape immune control.

Retinoic acids are potent inhibitors of spontaneous human eosinophil apoptosis.

Retinoic acids (RAs), which are active metabolites of vitamin A, are known to enhance Th2-type immune responses in vitro, but the role of RAs in allergic inflammatory cells remains unclear. In this study, we demonstrated that purified peripheral blood eosinophils expressed nuclear receptors for RAs at the mRNA and protein levels. Eosinophils cultured with all-trans RA (ATRA) and 9-cis-RA showed dramatically induced cell survival and nuclear hypersegmentation, and the efficacy of RAs (10(-6)M) was similar to that of IL-5 (1 ng/ml), the most critical cytokine for eosinophil activation. Pharmacological manipulation with receptor-specific agonists and antagonists indicated that the antiapoptotic effect of RAs was mediated through ligand-dependent activation of both retinoid acid receptors and retinoid X receptors (mainly retinoid acid receptors). Furthermore, using a gene microarray and a cytokine Ab array, we discovered that RAs induced vascular endothelial growth factor, M-CSF, and MCP-1 secretion, although they were not involved in eosinophil survival. RA-induced eosinophil survival appears to be associated with down-regulation of caspase 3 and inhibition of its enzymatic activity. These findings indicate an important role of RAs in homeostasis of granulocytes and provide further insight into the cellular and molecular pathogenesis of allergic reactions.

Role of soluble tumor necrosis factor-related apoptosis-inducing ligand concentrations after stem cell transplantation.

Although stem cell transplantation (SCT) is being used for hematopoietic reconstitution following high-dose chemotherapy for malignancy, it involves certain serious transplant-related complications such as graft-versus-host disease (GVHD). Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) plays important roles in regulating cell death, immune response, and inflammation. However, the role of soluble TRAIL (sTRAIL) after SCT is poorly understood. In this study, 42 patients underwent SCT; 22 patients received allogeneic SCT, while the remaining 20 received autologous SCT. In these patients, levels of sTRAIL, cytokines, and soluble factors were measured by enzyme-linked immunosorbent assay (ELISA). In addition, a basic study of the generation of endothelial cell-derived microparticle (EDMP) by TNF-alpha and soluble Fas ligand (sFasL) was conducted. sFasL and EDMP exhibited significant elevation in the early phase (2-3 weeks) after SCT. In addition, the elevation of IL-6, TNF-alpha, and sIL-2R after allogeneic SCT was observed. EDMP also exhibited changes similar to sFasL. The patients with high sTRAIL exhibited significant decrease of sFasL and EDMP as compared with those without high sTRAIL. TNF-alpha and sFasL induced an increase in procoagulant and apoptotic markers in endothelial cells, and EDMP shedding was observed. Furthermore, sTRAIL inhibited the EDMP elevation caused by TNF-alpha and sFasL. The apoptotic markers such as sFasL and sTRAIL exhibited particular changes after SCT. Our results suggest that sTRAIL generation after allogeneic SCT relates to the prevention of GVHD.

The significance of immunohistochemistry in the skin pathergy reaction of patients with Behçet's syndrome.

BACKGROUND: Behçet's syndrome is a chronic systemic immuno-inflammatory disorder affecting multiple organs with generalized vasculitis of arteries and veins. Although the aetiology is still unknown, endothelial dysfunction is one of the most prominent features in Behçet's syndrome. The skin pathergy reaction (SPR) is a non-specific hyperreactive lesion formation that is one of the major features and diagnostic criteria of the disease. It develops after 24-48 h at the site of the needle-prick, especially in the exacerbation period, and it is very similar to the erythematous papules or pustules that appear spontaneously in patients with Behçet's syndrome. Therefore, an investigation into the formation of the SPR lesion may contribute to the pathophysiology of skin lesions of this unique disorder. OBJECTIVE: To evaluate the immunological features of SPR formation by assessing the immunohistochemical staining of cell adhesion molecules and endothelial growth factor markers such as E-selectin, P-selectin and endoglin (CD 105). METHODS: Patients with Behçet's syndrome showing positive (n = 15) or negative (n = 10) SPR and 15 age- and sex-matched hospital-based healthy control subjects from a similar ethnic background were included in this study. Patients were divided into active and inactive stage by clinical findings and acute-phase reactant parameters including erythrocyte sedimentation rate (ESR) and neutrophil count. Punch biopsy specimens were obtained both from the lesion site on the forearms at 48 h and from normal skin approximately 5 cm adjacent to the SPR site. A biopsy was also obtained from the test application site in Behçet's syndrome patients with negative SPR and healthy volunteers. Biopsy specimens were then evaluated by immunohistochemical staining. RESULTS: Immunohistochemical examination demonstrated a mixed inflammatory cell infiltrate around the vessels and skin appendages that extended somewhat into the deep dermis. A positive segmental staining of E-selectin and P-selectin was noted in the endothelial cells of biopsies obtained from the patients with positive SPR. A positive segmental staining of CD 105 in the endothelial cells was also observed in the same group of patients. However, the immunostaining of the same markers was found to be negative in the biopsies obtained from normal skin of SPR-positive patients, SPR-negative patients and healthy control subjects. Both acute-phase reactant levels were significantly higher in the active stage than in inactive patients or healthy controls. CONCLUSION: Interaction of cellular adhesion molecules together with endothelial proliferation may play an important role in the formation of SPR lesions in patients with Behçet's syndrome. The involvement of the vascular endothelium in a large number of diseases including Behçet's syndrome supports the importance of vascular-specific adhesion molecules for their aetiopathogenesis.

COX-2/VEGF-dependent facilitation of tumor-associated angiogenesis and tumor growth in vivo.

Nonsteroidal anti-inflammatory drugs are known to suppress the occurrence and progression of malignancies such as colorectal cancers. However, the precise mechanism of these actions remains unknown. We have evaluated the role of an inducible cyclo-oxygenase (COX-2) in tumor-associated angiogenesis and tumor growth, and identified the downstream molecules involved using a ddy mouse model of sponge angiogenesis, which mimics tumor angiogenesis and is COX-2 and vascular endothelial growth factor (VEGF) dependent. In this model, VEGF expression was down-regulated by selective COX-2 inhibition with NS-398. To find out the involvement of COX-2/VEGF pathway in tumor-associated angiogenesis, we estimated angiogenesis occurring around implanted Millipore chambers containing sarcoma-180 (S-180) cells or Lewis lung carcinoma cells. Daily oral administration of NS-398 or of aspirin, a nonselective COX inhibitor, suppressed angiogenesis seen around the Millipore chambers. S-180 cells implanted in ddy mice formed substantial tumors with extensive angiogenesis markedly suppressed by aspirin and COX-2 inhibitors NS-398 and JTE522, but not by mofezolac, an inhibitor of constitutive COX-1. Tumor-associated angiogenesis was also significantly suppressed by a neutralizing antibody against VEGF. S-180 tumor growth in the subcutaneous tissues was also suppressed by aspirin, COX-2 selective inhibitors, and the VEGF antibody, but not by the COX-1 inhibitor. These results demonstrate that the inhibition of the COX-2/VEGF-dependent pathway was effective in tumor-associated angiogenesis, tumor growth, and tumor metastasis.

Single-chain antibody and its derivatives directed against vascular endothelial growth factor: application for antiangiogenic gene therapy.

Single-chain antibodies (scFv) have an enormous potential for clinical application. However, rapid blood clearance and difficulties in large-scale production of active scFvs have limited the practical use of these antibody fragments. Recently, an anti-vascular endothelial growth factor (VEGF) scFv (scFv V65) was selected in our laboratory from a human antibody phage-display library. This antibody was able to reduce tumor growth in mice by approximately 50%. Here, we employ a gene therapy strategy for sustained in vivo expression of scFv V65 and its derivatives. scFv fusion proteins containing parts of the constant IgG1 region were generated (minibody and scFv V65-Fc) to increase the serum half-life of the scFv V65. Systemic administration of recombinant adenovirus encoding scFv V65 resulted in substantial tumor inhibition. This effect could be improved by multiple virus injections. We found that the efficacy of different scFv V65 formats was dependent on the mode of administration: whereas scFv V65-Fc was the most efficient when expressed locally, scFv V65 was superior when delivered systemically. Our results show that therapeutic levels of scFv V65 can be obtained by systemic injection of recombinant adenoviruses. Therefore, therapeutic gene delivery of scFv is a feasible strategy that overcomes several limitations of conventional antibody therapy.

Anti-angiogenesis in cancer therapy.

OBJECTIVE: To review tumor angiogenesis, identify potential targets for anti-angiogenic cancer therapy, and highlight certain anti-angiogenic agents in clinical trials. DATA SOURCE: Research articles, abstracts, review articles, and book chapters. CONCLUSION: Tumor angiogenesis is a complex, multistep process that provides a target for antineoplastic therapy whereby tumor neovasculature is interrupted at various steps in the angiogenic process. Clinical trials are investigating the application and efficacy of anti-angiogenic agents. IMPLICATIONS FOR NURSING PRACTICE: Oncology nurses must continually increase their knowledge with the onset of newer, targeted agents. This will provide a background for educating and caring for the patient who is receiving anti-angiogenic therapy.

Vascular endothelial growth factor expression, beta-catenin tyrosine phosphorylation, and endothelial proliferative behavior: a pathway for transformation?

The hypothesis that tumor growth is angiogenesis dependent has been documented by a considerable body of direct and indirect experimental data and has generated intense basic and pharmaceutical-related interest. In contrast, the study of endothelial cell tumors has been modest by comparison. Hemangioma is the most common tumor of any kind seen in infancy and also, perhaps, the least understood. We compared a mouse hemangioma-derived cell line (EOMA) and primary human endothelial cells (HUVEC) for their proliferative behavior and molecular alterations. EOMA cells intrinsically expressed vascular endothelial growth factor (VEGF), which acts in an autocrine manner, resulting in an increase in CD1 expression and cell proliferation, both of which were inhibited by anti-VEGF neutralizing antibodies. Such an autocrine loop is supported by constitutive VEGF receptor (Flk-1) tyrosine phosphorylation, Flk-1 and Flt-1 nuclear localization, and mitogen-activated protein kinase activation. beta-catenin was also found to exhibit significant nuclear localization and constitutively associate with Flk-1 and Flt-1 in EOMA cells but much less so in HUVEC, and immunoprecipitated Flk-1 was able to phosphorylate purified beta-catenin in an immune complex kinase assay. EOMA cells were also noted to express reduced levels of N-cadherin and gamma-catenin compared with HUVEC. Interestingly, sequestration of endogenous VEGF in EOMA cultures resulted in a dramatic decrease in nuclear beta-catenin and a reduction in CD1 levels, whereas addition of exogenous VEGF elicited increased nuclear beta-catenin localization and increased CD1 levels in HUVEC. The possible contributions of VEGF signaling pathways, cell junction component expression levels, and phosphorylation states to endothelial cell transformation and proliferation are discussed.

VEGF164-mediated inflammation is required for pathological, but not physiological, ischemia-induced retinal neovascularization.

Hypoxia-induced VEGF governs both physiological retinal vascular development and pathological retinal neovascularization. In the current paper, the mechanisms of physiological and pathological neovascularization are compared and contrasted. During pathological neovascularization, both the absolute and relative expression levels for VEGF164 increased to a greater degree than during physiological neovascularization. Furthermore, extensive leukocyte adhesion was observed at the leading edge of pathological, but not physiological, neovascularization. When a VEGF164-specific neutralizing aptamer was administered, it potently suppressed the leukocyte adhesion and pathological neovascularization, whereas it had little or no effect on physiological neovascularization. In parallel experiments, genetically altered VEGF164-deficient (VEGF120/188) mice exhibited no difference in physiological neovascularization when compared with wild-type (VEGF+/+) controls. In contrast, administration of a VEGFR-1/Fc fusion protein, which blocks all VEGF isoforms, led to significant suppression of both pathological and physiological neovascularization. In addition, the targeted inactivation of monocyte lineage cells with clodronate-liposomes led to the suppression of pathological neovascularization. Conversely, the blockade of T lymphocyte-mediated immune responses with an anti-CD2 antibody exacerbated pathological neovascularization. These data highlight important molecular and cellular differences between physiological and pathological retinal neovascularization. During pathological neovascularization, VEGF164 selectively induces inflammation and cellular immunity. These processes provide positive and negative angiogenic regulation, respectively. Together, new therapeutic approaches for selectively targeting pathological, but not physiological, retinal neovascularization are outlined.

A randomized trial of bevacizumab, an anti-vascular endothelial growth factor antibody, for metastatic renal cancer.

BACKGROUND: Mutations in the tumor-suppressor gene VHL cause oversecretion of vascular endothelial growth factor by clear-cell renal carcinomas. We conducted a clinical trial to evaluate bevacizumab, a neutralizing antibody against vascular endothelial growth factor, in patients with metastatic renal-cell carcinoma. METHODS: A randomized, double-blind, phase 2 trial was conducted comparing placebo with bevacizumab at doses of 3 and 10 mg per kilogram of body weight, given every two weeks; the time to progression of disease and the response rate were primary end points. Crossover from placebo to antibody treatment was allowed, and survival was a secondary end point. RESULTS: Minimal toxic effects were seen, with hypertension and asymptomatic proteinuria predominating. The trial was stopped after the interim analysis met the criteria for early stopping. With 116 patients randomly assigned to treatment groups (40 to placebo, 37 to low-dose antibody, and 39 to high-dose antibody), there was a significant prolongation of the time to progression of disease in the high-dose--antibody group as compared with the placebo group (hazard ratio, 2.55; P<0.001). There was a small difference, of borderline significance, between the time to progression of disease in the low-dose--antibody group and that in the placebo group (hazard ratio, 1.26; P=0.053). The probability of being progression-free for patients given high-dose antibody, low-dose--antibody, and placebo was 64 percent, 39 percent, and 20 percent, respectively, at four months and 30 percent, 14 percent, and 5 percent at eight months. At the last analysis, there were no significant differences in overall survival between groups (P>0.20 for all comparisons). CONCLUSIONS: Bevacizumab can significantly prolong the time to progression of disease in patients with metastatic renal-cell cancer.