Clinical evaluation of radioimmunoimaging with 131I-C0C183B2 monoclonal antibody against ovarian carcinoma by intraperitoneal injection

Development of an immunocytokine, IL-2-183B2scFv, for targeted immunotherapy of ovarian cancer

OBJECTIVES

The purpose of this study was to develop an immunocytokine for immunotherapy of human ovarian cancer.

METHODS

The single-chain Fv of a monoclonal antibody, COC183B2, specific for an ovarian carcinoma-associated antigen (OC183B2), was genetically fused with the coding sequence of interleukin 2 (IL-2). The fusion protein, also called immunocytokine, IL-2-183B2scFv, was expressed in CHO cells and examined for its specificity and biological function.

RESULTS

The immunocytokine, IL-2-183B2scFv, retained the functions of both the antibody and IL-2. It was able to target IL-2 to tumor cells that overexpress OC183B2, and stimulate the proliferation of an IL-2-dependent cell line, CTLL-2.

CONCLUSIONS

The IL-2-183B2scFv maintains the functions of both IL-2 and antibody. It can be potentially used for immunotherapy of ovarian cancer by delivering a high concentration of IL-2 to OC183B2-expressing ovarian cancer cells.

Radioimmunoscintigraphy in patients with ovarian cancer

The use of radiolabeled monoclonal antibodies (MoAbs) has significantly improved the ability to detect tumor antigens, thus improving in vivo tumor diagnosis and treatment. The management of ovarian carcinoma still poses a challenging medical problem. Clinical trials using radioimmunoscintigraphy or a hand-held gamma detection probe intraoperatively were performed in patients with clinical evidence of primary or recurrent ovarian cancer. Immunoscintigraphy of ovarian cancer lesions has been performed mainly with 99mTc, 111In and 123I labeled with HMFG1, HMFG2, OC-125, B72.3, H17E2, OVTL3, MoAb170, Mov18 and other MoAbs. Antibody guided imaging using radioimmunoscintigraphy has demonstrated improved targeting of ovarian cancer, resulting in a highly sensitive and specific method. However, it is not yet known which type of MoAb is the most efficient for radioimmunoscintigraphy. Since these tumors represent a potentially curable disease, radioimmunoscintigraphy could contribute mainly to accurate staging as a supplementary to conventional diagnostic methods, as well as for the localization of active disease after chemotherapy and monitoring for the presence of recurrent disease. Nevertheless, prospective studies in a large number of patients should be undertaken in order to further evaluate the diagnostic contribution of this approach.