Immunoconjugates Are Better in Theory Than Practice

Implications: Immunomedics has developed three new immunoconjugates between monoclonal antibodies and SN-38 i an effort to target colon, pancreas and lung cancer.  Preclinical data are effective in a metastatic colon cancer model but there are no clinical data.

Analysis: Immunoconjugates have been under clinical investigation for more than 20 years and no a single compound has been approved for the therapy of solid tumors.  There is no reason to believe that these compounds developed by Immunomedics will be any different.  Issues of penetration, antigen density, binding affinity, cytotoxicity and adverse reactions remain to be defined.  Preclinical data with this class of drugs has proved clinically irrelevant in study after study.  This announcement gives no cause for excitement.