Efficacy of the Antibody-Drug Conjugate W0101 in Preclinical Models of IGF-1 Receptor Overexpressing Solid Tumors.

The insulin-like growth factor type 1 receptor (IGF-1R) is important in tumorigenesis, and its overexpression occurs in numerous tumor tissues. To date, therapeutic approaches based on mAbs and tyrosine kinase inhibitors targeting IGF-1R have only shown clinical benefit in specific patient populations. We report a unique IGF-1R-targeted antibody-drug conjugate (ADC), W0101, designed to deliver a highly potent cytotoxic auristatin derivative selectively to IGF-1R overexpressing tumor cells. The mAb (hz208F2-4) used to prepare the ADC was selected for its specific binding properties to IGF-1R compared with the insulin receptor, and for its internalization properties. Conjugation of a novel auristatin derivative drug linker to hz208F2-4 did not alter its binding and internalization properties. W0101 induced receptor-dependent cell cytotoxicity in vitro when applied to various cell lines overexpressing IGF-1R, but it did not affect normal cells. Efficacy studies were conducted in several mouse models expressing different levels of IGF-1R to determine the sensitivity of the tumors to W0101. W0101 induced potent tumor regression in certain mouse models. Interestingly, the potency of W0101 correlated with the expression level of IGF-1R evaluated by IHC. In an MCF-7 breast cancer model with high-level IGF-1R expression, a single injection of W0101 3 mg/kg led to strong inhibition of tumor growth. W0101 provides a potential new therapeutic option for patients overexpressing IGF-1R. A first-in-human trial of W0101 is currently ongoing to address clinical safety.

A New Anti-CXCR4 Antibody That Blocks the CXCR4/SDF-1 Axis and Mobilizes Effector Cells.

The type IV C-X-C-motif chemokine receptor (CXCR4) is expressed in a large variety of human cancers, including hematologic malignancies, and this receptor and its ligand, stromal cell-derived factor-1 (SDF-1), play a crucial role in cancer progression. We generated a humanized immunoglobulin G1 mAb, hz515H7, which binds human CXCR4, efficiently competes for SDF-1 binding, and induces a conformational change in CXCR4 homodimers. Furthermore, it inhibits both CXCR4 receptor-mediated G-protein activation and ß-arrestin-2 recruitment following CXCR4 activation. The binding of the hz515H7 antibody to CXCR4 inhibits the SDF-1-induced signaling pathway, resulting in reduced phosphorylation of downstream effectors, such as Akt, Erk1/2, p38, and GSK3ß. Hz515H7 also strongly inhibits cell migration and proliferation and, while preserving normal blood cells, induces both antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity against neoplastic cells. In mouse xenograft models, hz515H7 displays antitumor activities with multiple hematologic tumor cell lines, with its Fc-mediated effector functions proving essential in this context. Furthermore, hz515H7 binds to primary tumor cells from acute myeloid leukemia and multiple myeloma patients. Collectively, our results demonstrate two major mechanisms of action, making hz515H7 unique in this regard. Its potential as a best-in-class molecule is currently under investigation in a phase I clinical trial. Mol Cancer Ther; 15(8); 1890-9. ©2016 AACR.

Functional responses and in vivo anti-tumour activity of h7C10: a humanised monoclonal antibody with neutralising activity against the insulin-like growth factor-1 (IGF-1) receptor and insulin/IGF-1 hybrid receptors.

A novel humanised monoclonal antibody (Mab, h7C10) was raised against the human insulin-like growth factor-1 receptor (IGF-1R); it exhibited potent inhibition of tumour growth in animal models. Further evaluation of its inhibitory activity at hybrid receptors (Hybrid-Rs) composed of the association between IGF-1R and insulin receptor (IR) was performed. Selective, potent and efficacious inhibition of [(125)I]IGF-1 binding as well as IGF-1- and IGF-2-mediated receptor phosphorylation was demonstrated at both IGF-1R and Hybrid-Rs, without activity at IR. Ligand-independent down-regulation of both IGF-1R and Hybrid-Rs was obtained upon long-term association with h7C10. In vivo evaluation was performed in a MDA-MB-231 xenograft mouse model, showing a 14-fold higher level of Hybrid-Rs as compared to IGF-1R. A more potent anti-tumoural response was obtained for h7C10 as compared to Mabs targeting solely IGF-1R or Hybrid-Rs. The herewith described neutralising properties of h7C10 as potent inhibitor of both IGF-1R and Hybrid-Rs are likely to participate in its anti-tumoural activities and maybe of interest for therapeutic applications.

In vivo follow-up of rat tumor models with 2-deoxy-2-[F-18]fluoro-D-glucose/dual-head coincidence gamma camera imaging.

UNLABELLED: Before studying the impact of 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) imaging with a dual-head coincidence gamma camera (DHC) for the follow-up of animal tumor models, we wanted to optimize this technique. METHODS: Three different animal tumor models (osteosarcoma, melanoma, and breast cancer) were studied after FDG injection. Dynamic and dual time point FDG/DHC imaging were studied from one hour to five hours postinjection. In vitro tumor cell FDG uptake was assessed in eight different tumor cell lines. In one model (osteosarcoma), tumor growth, lung metastasis emergence, and survival were assessed by classical clinical follow-up and compared to FDG imaging in a control group (n = 6) and in a group treated by endostatin liposome complexes (n = 6). RESULTS: Images obtained five hours after injection were more reliable for tumor growth follow-up than standard images (one hour). In vitro tumor cell FDG uptake confirmed in vivo imaging studies. In eight different tumor cell lines the FDG uptake was higher after five hours incubation than after one hour (p < 0.002). With FDG follow-up, we found that FDG uptake was strongly correlated with survival and that lung metastasis larger than 5 mm could be detected. CONCLUSION: Using the optimization proposed above, DHC/FDG functional imaging seems to be a powerful tool to study rat tumor models and to help develop novel cancer therapies.

A new orthotopic model of human breast cancer in immunocompetent rats.

BACKGROUND: Breast cancer is the first cause of mortality by cancer in women in North America and Western Europe. For non-estrogen-dependent tumors as well as for metastatic cancers, current therapies are of limited efficacy. Several animal models have been described but they are imperfect as they are poorly representative of what occurs in real tumors. To overcome some of these limitations, we describe a new orthotopic model of estrogen-independent breast cancer in immunocompetent rats treated with cyclosporin A (CysA). MATERIALS AND METHODS: Injection of cell suspensions of human breast MDA-MB-231 cancer cells into the mammary fat pad or subcutaneous grafts of solid tumor sections were performed on Sprague Dawley rats receiving intraperitoneally 35 mg/kg of CysA. Tumor growth was measured and monitored by scintigraphy using 18FDG and 99mTc-MIBI. RESULTS: In both models, tumors grew well but growth rates were different. Cell suspension injections gave rise to tumors with a higher growth rate and the tumors obtained infiltrated the mammary and giving results closer to human pathology. CONCLUSION: This animal model with injected cells may provide a new adequate tool for studying breast cancer and developing new therapy strategy.