Safety and Tolerability of a Novel Anti-HER2 Antibody-Drug Conjugate (PF-06804103) in Patients with HER2-Expressing Solid Tumors: A Phase 1 Dose-Escalation Study.

PF-06804103 is an anti-HER2 antibody-drug conjugate with auristatin payload. We evaluated its safety, tolerability, and antitumor activity in patients with advanced/unresectable or metastatic breast and gastric cancers. This multicenter, open-label, first-in-human, phase 1 study (NCT03284723) comprised dose escalation (P1) and dose expansion (P2).

Pixelwise H-score: A novel digital image analysis-based metric to quantify membrane biomarker expression from immunohistochemistry images.

Immunohistochemistry (IHC) assays play a central role in evaluating biomarker expression in tissue sections for diagnostic and research applications. Manual scoring of IHC images, which is the current standard of practice, is known to have several shortcomings in terms of reproducibility and scalability to large scale studies. Here, by using a digital image analysis-based approach, we introduce a new metric called the pixelwise H-score (pix H-score) that quantifies biomarker expression from whole-slide scanned IHC images.

NOTCH3-targeted antibody drug conjugates regress tumors by inducing apoptosis in receptor cells and through transendocytosis into ligand cells.

Aberrant NOTCH3 signaling and overexpression is oncogenic, associated with cancer stem cells and drug resistance, yet therapeutic targeting remains elusive. Here, we develop NOTCH3-targeted antibody drug conjugates (NOTCH3-ADCs) by bioconjugation of an auristatin microtubule inhibitor through a protease cleavable linker to two antibodies with differential abilities to inhibit signaling. The signaling inhibitory antibody rapidly induces ligand-independent receptor clustering and internalization through both caveolin and clathrin-mediated pathways.

A phase I, dose-escalation study of PF-06650808, an anti-Notch3 antibody-drug conjugate, in patients with breast cancer and other advanced solid tumors.

Background PF-06650808 is a novel anti-Notch3 antibody-drug conjugate (ADC) able to deliver an auristatin-based cytotoxic payload to target cells. In this first-in-human, dose-finding, phase I study (NCT02129205), we investigated safety, pharmacokinetics, immunogenicity, and preliminary antitumor activity of single-agent PF-06650808 in 40 patients with advanced breast cancer (BC) and other solid tumors unselected for Notch3 expression. Primary endpoint was dose-limiting toxicity (DLT).

First-in-human, phase I study of PF-06647263, an anti-EFNA4 calicheamicin antibody-drug conjugate, in patients with advanced solid tumors.

PF-06647263, a novel antibody-drug conjugate consisting of an anti-EFNA4 antibody linked to a calicheamicin payload, has shown potent antitumor activity in human xenograft tumor models, including triple-negative breast cancer (TNBC). In the dose-escalation part 1 of this multicenter, open-label, phase I study (NCT02078752), successive cohorts of patients (n, 48) with advanced solid tumors and no available standard therapy received PF-06647263 every 3 weeks (Q3W) or every week (QW), following a modified toxicity probability interval (mTPI) method (initial dosing: 0.015 mg/kg Q3W).

Detecting expression of 5T4 in CTCs and tumor samples from NSCLC patients.

The fetal oncogene 5T4 is a cell surface protein, with overexpression observed in a variety of cancers as compared to normal adult tissue. The ability to select patients with tumors that express high levels of 5T4 may enrich a clinical trial cohort with patients most likely to respond to 5T4 targeted therapy. To that end, we developed assays to measure 5T4 in both tumors and in circulating tumor cells (CTCs).

Efficacy of Cotargeting Angiopoietin-2 and the VEGF Pathway in the Adjuvant Postsurgical Setting for Early Breast, Colorectal, and Renal Cancers.

Antiangiogenic tyrosine kinase inhibitors (TKI) that target VEGF receptor-2 (VEGFR2) have not been effective as adjuvant treatments for micrometastatic disease in phase III clinical trials. Angiopoietin-2 (Ang2) is a proangiogenic and proinflammatory vascular destabilizer that cooperates with VEGF. The purpose of this study was to test whether CVX-060 (an Ang2-specific CovX-body) can be combined with VEGFR2-targeting TKIs (sunitinib or regorafenib) to successfully treat postsurgical metastatic disease in multiple orthotopically implanted human tumor xenograft and syngeneic murine tumor models.

Predictive markers of efficacy for an angiopoietin-2 targeting therapeutic in xenograft models.

The clinical efficacy of anti-angiogenic therapies has been difficult to predict, and biomarkers that can predict responsiveness are sorely needed in this era of personalized medicine. CVX-060 is an angiopoietin-2 (Ang2) targeting therapeutic, consisting of two peptides that bind Ang2 with high affinity and specificity, covalently fused to a scaffold antibody. In order to optimize the use of this compound in the clinic the construction of a predictive model is described, based on the efficacy of CVX-060 in 13 cell line and 2 patient-derived xenograft models.

The Effect of Molecular Weight, PK, and Valency on Tumor Biodistribution and Efficacy of Antibody-Based Drugs.

Poor drug delivery and penetration of antibody-mediated therapies pose significant obstacles to effective treatment of solid tumors. This study explored the role of pharmacokinetics, valency, and molecular weight in maximizing drug delivery. Biodistribution of a fibroblast growth factor receptor 4 (FGFR4) targeting CovX-body (an FGFR4-binding peptide covalently linked to a nontargeting IgG scaffold; 150 kDa) and enzymatically generated FGFR4 targeting F(ab)2 (100 kDa) and Fab (50 kDa) fragments was measured.

Antitumor efficacy of a thrombospondin 1 mimetic CovX-body.

CVX-045 is produced by covalently attaching a thrombospondin 1 (TSP-1) mimetic comprising a peptidic sequence and a linker to the Fab binding site of a proprietary scaffold antibody. CVX-045 possesses the potency of the TSP-1-derived peptide, along with the advantageous pharmacokinetics of an antibody. Antitumor activity of CVX-045 was evaluated in human xenograft models alone and in combination with standard chemotherapies and targeted molecules.

Evolution of potent and stable placental-growth-factor-1-targeting CovX-bodies from phage display peptide discovery.

Novel phage-derived peptides are the first reported molecules specifically targeting human placental growth factor 1 (PlGF-1). Phage data enabled peptide modifications that decreased IC(50) values in PlGF-1/VEGFR-1 competition ELISA from 100 to 1 μM. Peptides exhibiting enhanced potency were bioconjugated to the CovX antibody scaffold 1 (CVX-2000), generating bivalent CovX-Bodies with 2 nM K(D) against PlGF-1.

Specifically targeting angiopoietin-2 inhibits angiogenesis, Tie2-expressing monocyte infiltration, and tumor growth.

Purpose: Angiopoietin-1 (Ang1) plays a key role in maintaining stable vasculature, whereas in a tumor Ang2 antagonizes Ang1's function and promotes the initiation of the angiogenic switch. Specifically targeting Ang2 is a promising anticancer strategy. Here we describe the development and characterization of a new class of biotherapeutics referred to as CovX-Bodies, which are created by chemical fusion of a peptide and a carrier antibody scaffold.

Vitamin D binding protein-macrophage activating factor directly inhibits proliferation, migration, and uPAR expression of prostate cancer cells.

Background: Vitamin D binding protein-macrophage activating factor (DBP-maf) is a potent inhibitor of tumor growth. Its activity, however, has been attributed to indirect mechanisms such as boosting the immune response by activating macrophages and inhibiting the blood vessel growth necessary for the growth of tumors.

Methods And Findings: In this study we show for the first time that DBP-maf exhibits a direct and potent effect on prostate tumor cells in the absence of macrophages.

Selective activity against proliferating tumor endothelial cells by CVX-22, a thrombospondin-1 mimetic CovX-Body.

CVX-22 is a CovX-Body, produced by covalently attaching a thrombospondin-1 (TSP-1) type 1 repeat peptide mimetic to a humanized IgG1 molecule. To dissect the antiangiogenic mechanism of CVX-22, the numbers and proliferative status of defined tumor endothelial cell (TEC) subsets from the B16 and C32 melanoma models were examined. CVX-22 treatment reduced the numbers of activated, vascular endothelial growth factor receptor 2 (VEGFR2)-positive TECs.

Copper binding by tetrathiomolybdate attenuates angiogenesis and tumor cell proliferation through the inhibition of superoxide dismutase 1.

Purpose: A second-generation tetrathiomolybdate analogue (ATN-224; choline tetrathiomolybdate), which selectively binds copper with high affinity, is currently completing two phase I clinical trials in patients with advanced solid and advanced hematologic malignancies. However, there is very little information about the mechanism of action of ATN-224 at the molecular level.

Experimental Design: The effects of ATN-224 on endothelial and tumor cell growth were evaluated in cell culture experiments in vitro.

Vitamin D binding protein-macrophage activating factor (DBP-maf) inhibits angiogenesis and tumor growth in mice.

We have isolated a selectively deglycosylated form of vitamin D binding protein (DBP-maf) generated from systemically available DBP by a human pancreatic cancer cell line. DBP-maf is antiproliferative for endothelial cells and antiangiogenic in the chorioallantoic membrane assay. DBP-maf administered daily was able to potently inhibit the growth of human pancreatic cancer in immune compromised mice (T/C=0.

Treatment of human pancreatic cancer in mice with angiogenic inhibitors.

Tumor growth is dependent on the balance of positive and negative regulators of angiogenesis. Antiangiogenic compounds inhibit endothelial cell biology in vitro and angiogenesis in vivo. Therefore antiangiogenic therapy presumes to be an effective treatment for pancreatic cancer.

Regulation of angiogenesis by the hemostatic system.

In recent years it has become apparent that the hemostatic system has a role to play in regulating angiogenesis. This is achieved by components of the coagulation and fibrinolytic systems regulating proteolysis in the milieu and context of extra cellular matrix and the fibrin clot. It is also an emerging paradigm that cryptic fragments, released by proteolysis from components of the coagulation and fibrinolytic systems, have a role to play in regulating angiogenesis.