Preclinical Characterization of a Novel Monoclonal Antibody NEO-201 for the Treatment of Human Carcinomas.

NEO-201 is a novel humanized IgG1 monoclonal antibody that was derived from an immunogenic preparation of tumor-associated antigens from pooled allogeneic colon tumor tissue extracts. It was found to react against a variety of cultured human carcinoma cell lines and was highly reactive against the majority of tumor tissues from many different carcinomas, including colon, pancreatic, stomach, lung, and breast cancers. NEO-201 also exhibited tumor specificity, as the majority of normal tissues were not recognized by this antibody. Functional assays revealed that treatment with NEO-201 is capable of mediating both antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) against tumor cells. Furthermore, the growth of human pancreatic xenograft tumors in vivo was largely attenuated by treatment with NEO-201 both alone and in combination with human peripheral blood mononuclear cells as an effector cell source for ADCC. In vivo biodistribution studies in human tumor xenograft-bearing mice revealed that NEO-201 preferentially accumulates in the tumor but not organ tissue. Finally, a single-dose toxicity study in non-human primates demonstrated safety and tolerability of NEO-201, as a transient decrease in circulating neutrophils was the only related adverse effect observed. These findings indicate that NEO-201 warrants clinical testing as both a novel diagnostic and therapeutic agent for the treatment of a broad variety of carcinomas.

Monoclonal antibodies that target the immunogenic proteins expressed in colorectal cancer.

In an attempt to improve upon the end results obtained in treating colorectal cancer it was apparent that the earlier the diagnosis that could be obtained, the better the chance for obtaining desired results. In the case of more advanced tumors typified by later stage colorectal cancer, surgical debulking is an important part of the treatment strategy. Here the use of additional therapeutic modalities including chemotherapy and present day immunotherapy has failed to accomplish the desired improvements that have been sought after. Adjuvant therapy, has offered little to the overall survival. The concept of early detection is now recognized as the initial step in reaching proper end results and can readily be demonstrated from colorectal cancer studies. Here survival has been found to be a reflection of the stage at which the tumor is first identified and treated. When specific monoclonals targeting colorectal cancer are employed diagnostically, we have been able to demonstrate detection of colorectal cancer at its inception as a premalignant lesion, such that genotypic features can be identified before the phenotypic appearance of cancer can be noted.

Anti-tumor activity of a novel monoclonal antibody, NPC-1C, optimized for recognition of tumor antigen MUC5AC variant in preclinical models.

PURPOSE: NPC-1C is a chimeric immunoglobulin IgG1 developed from antigen tested in the Hollinshead tumor vaccine trials that recognizes an immunogenic MUC5AC-related tumor-associated antigen. In this article, we describe the pre-clinical characterization of this antibody that is currently being tested in human clinical trials. EXPERIMENTAL DESIGN: The specificity of NPC-1C for pancreatic and colorectal cancer cell lines was tested by flow cytometry assays and immunohistochemical staining. Antibody-dependent cell cytotoxicity was measured using a tumor cell line lysis assay. Anti-tumor efficacy and biodistribution were assessed in nude mice bearing human pancreatic tumor xenografts. RESULTS: Human tumor cell binding measured by flow cytometry ranged from 52 to 94 % of cells stained positive with NPC-1C in three colorectal and one pancreatic cell lines, while IHC demonstrated staining of 43 % of colon cancers and 48 % of pancreatic cancer tissues, with little or no cross-reactivity of NPC-1C with normal colon or pancreas tissues. In vitro NPC-1C-mediated tumor cell killing occurred in a median of 44.5 % of four colorectal and three pancreatic tumor cell lines. In vivo anti-tumor efficacy in a human pancreatic CFPAC-1 tumor xenograft model was demonstrated with a twofold to threefold reduction in tumor growth in the NPC-1C-treated mice compared to saline and human IgG controls. Pharmacodynamic studies indicate NPC-1C localizes in antigen-positive tumors and has minimal uptake in normal mouse tissues. CONCLUSIONS: NPC-1C, a chimeric monoclonal antibody that reacts with a MUC5AC-related antigen expressed by pancreatic and colorectal tumor tissues, has promising preclinical activity in pancreatic and colorectal adenocarcinoma.

Nanocytology vs. Immunohistochemistry of Intestinal Colonocytes to Assess the Risk of Colon Cancer based on Field Cancerization - A Preliminary Report.

The ability to define malignancy in its earliest stages of development is an essential part of any program aimed at attempting to cure the malignant condition. In terms of colon cancer various approaches have been employed to define the transformation of colonocytes as they progress to the fully malignant phenotype. Approaches ranging from nanocytology to mass spectroscopy have been utilized with limited success.Our group at Precision Biologics has been able to define three distinct immunogenic proteins, most oncofetal in origin, which are expressed to various degrees in colon cancer and are essentially absent from normal colon tissue. Monoclonal antibodies (mAbs) have been developed against these tumor associated antigens (TAA), which is NPC-1, 31.1 and 16C3. Each, have shown significant ADCC in the presence of the tumor cells grown in culture. Studies were performed to clarify at what stage in the development of the colon cancer do such TAA proteins begin to be expressed. Utilizing Immunohistochemistry (IHC) with the mAbs targeting the TAA's, we have been able to demonstrate that such antigens appear in the cytoplasm as early as 6 or more months prior to the phenotypic appearance of malignancy utilizing H&E staining.Kits containing these colon Ca monoclonals from our lab, as well as positive and negative controls have been produced for use in the operating room to examine colonocytes at the margin of resection following colectomy; this in order to assure that transforming cells are not incorporated into an anastomosis. We have also been able to demonstrate that premalignant cells as well as those cells present in a fully malignant lesion do shed their antigens into the lumen of the bowel. As such, we have been able to show that a simple "office" stool ELISA can predict with a high degree of accuracy whether a premalignant polypoid lesion, a fully malignant adenocarcinoma or a totally normal colon free of any neoplastic process is present and thus decide on the need for or not, of performing colonoscopy.

The use of specific monoclonal antibodies to target immunogenic tumor membrane proteins in patients with recurrent pancreatic and colon cancer.

Tumor associated antigens from pooled allogeneic membrane proteins were isolated, partially purified and tested as a possible vaccine in patients with stage II and III colon cancer. The vaccine, when given in combination with an adjuvant following surgical resection, resulted in marked improvement in survival compared to control patients having only undergone surgical resection of their tumor. While it was possible to demonstrate that patients receiving vaccine turned on both humoral and cell mediated responses, it appears that survivors remaining free of disease at 5-7 yrs post op were able to mount a strong IgG1 response as the primary mechanism for tumor destruction. Antibodies from hybridomas made against the vaccines resulted in production of monoclonals with a high degree of ADCC. Those monoclonals targeting pancreatic cancer and in particular the MUC5ac mutated antigen representing tumor immunogen were studied in detail. Animal models indicated rapid tumor destruction when nude mice, injected with human pancreatic cancer were then immunized with NPC-1 monoclonal antibody targeting mutated MUC5ac. FDA studies including tissue cross reactivity, biodistribution, and cytokine release assays indicated safety and efficacy of the monoclonals we have developed. Submission of the IND allowed for initiation of the Phase I trial using mAb NPC-1 targeting pancreatic cancer when that antigen was found to be expressed.