Clinical application of anti-carcinoma human monoclonal antibody

A human monoclonal antibody SKI (HuMAb SK1) recognizes a 42-46 KDa sialoglycoprotein which is commonly expressed on carcinoma tissues. In order to examine the in vivo accumulation capacity of SK1, immunoscintigraphy was performed in colorectal cancer patients. Under informed consent, 4 patients with suspected recurrent colorectal cancers were entered into the study. On day I, 1-2mg of biotinylated SK1 was administered intravenously to each patient. On day 2, 5mg of streptavidin was administered, followed one day later, biotinylated (InCl3)-In-111 was administered. Either planar or SPECT (single photon emission tomography) images were obtained 6 to 24 hours later. Two cases out of three histologically-proven local pelvic recurrences were successfully imaged with this protocol. One case who had been diagnosed as local recurrence by a computed tomography (CT), and a magnetic resonance imaging (MRI) was true-negative in immunoscintigraphy. No side effects were observed. These findings suggested that HuMAb SK1 effectively accumulates to the tumor regions in vivo. In addition, it was also suggested that immunoscintigraphy using SKI is a safe and an effective approach for the detection of local recurrence of rectal cancers.