Until the advent of targeted therapies, dealing with cancer, outside of surgery, was not unlike waging guerrilla warfare on an enemy of unknown size: destroying the whole village was one fear, not knowing how many soldiers lurked in the surrounding hillsides, another.
But new monoclonal antibodies and small molecule drugs are designed to concentrate cytotoxicity where needed and reduce damage elsewhere in the body--unlike the one-poison-kills-all-tumors approach that is chemotherapy. Their designs, however, are not perfect, not by a long shot.
Among nearly 80 oncology Food and Drug Administration approvals since 1995, the few related to nonspecific chemotherapeutics have been mostly innovations in drug delivery. Gliadel (polifeprosan 20 with carmustine implant), for example, helps carmustine kill brain tumor cells by circumventing its feeble ability to penetrate the blood-brain barrier. Neurosurgeons implant carmustine-impregnated Gliadel wafers into cavities left after tumor removal. The wafers slowly release the drug near remaining tumor cells ...
