Clinical and biochemical effects in vivo of monoclonal antitumor antibody in Verner-Morrison's syndrome

Background. Monoclonal antibodies have not been evaluated in metastasizing endocrine tumors, even though these lesions may induce severe morbidity of hormone excess in absence of considerable tumor burden. Methods. A murine monoclonal antibody of the IgG2a subtype was generated by immunization with dispersed tumor cells from an endocrine pancreatic carcinoma associated with liver and peritoneal metastases as well as a therapy-resistant Verner-Morrison's syndrome. Results. Immunohistochemical staining disclosed selective tissue reactivity of the antibody and conspicuous immunostaining on the surface of the tumor cells. Infusion of 100 mg antibody over 2 days into the common hepatic artery of the patient was accompanied by reduced diarrhea volume until death 6 weeks later and transient elevation of total plasma immunoreactivity for vasoactive intestinal peptide due to large molecular forms of the peptide. Postmortem examination demonstrated disappearance of peritoneal metastases as well as absence of immunostaining for the injected antibody and the transferrin receptor within residual hepatic tumors. Conclusion. The results substantiate that symptomatic alleviation and perhaps interference with tumor cell mass may be obtained with monoclonal antibodies in patients with endocrine tumors and that the antiidiotypic immunoglobulin response may play a role herein. Cancer 1994; 73:1346–52.