Still little information is available on the efficacy and toxicity of anti-Trop-2
antibodies in man. Findings on
antibodies anti-Trop-1/
Ep-CAM, a paralog molecule of Trop-2, may provide preliminary indications, and a low-affinity anti-Trop-1/
Ep-CAM monoclonal antibody, failed to show any benefit in
colon cancer patients. Other anti-Trop-1
antibodies, e.g. MT201, may bear more promise, as may more advanced molecular forms, e.g. a
BiTE design (MT110) or trifunctional
antibodies (
catumaxomab). However, the efficacy of these
reagents in
cancer patients still needs to be proven in randomized clinical trials. As for toxicity, the administration of ING-1, a high-affinity, human-engineered anti-Trop-1/
Ep-CAM monoclonal antibody, caused cases of
acute pancreatitis. The exocrine pancreas also expresses Trop-2. Hence, similar concerns should apply to the administration of anti-Trop-2
monoclonal antibodies to patients. More in general, contrary to the statements by Cubas et al., Trop-2/T-16/Mov-16 is expressed by several normal tissues in man, e.g. epidermis, exocervix, esophagus, tongue, urothelium, kidney, pancreas, trophoblast and breast. Hence, additional effort is required to develop Trop-2 into a useful immunotherapeutic target, by increasing anti-Trop-2 antibody efficacy, while keeping under control toxicity on expressing normal tissues.