One in three people will be diagnosed with cancer during their lifetime and around one in five will die from it. Cancer is the major cause of death in the developed world. Although earlier diagnosis and the introduction of new and/or improved treatments have led to dramatic increases in survival rate for certain types of cancer, for most common malignancies there remains a great need for the development of more effective therapies. The increasing cancer incidence associated with the aging population adds to this need.
Surgery is the most effective modality in the treatment of solid tumours. However, many cancers have already infiltrated the surrounding normal tissues or disseminated to other parts of the body before diagnosis. Radiotherapy is also effective, when used either as a single modality or in combination with surgery, in the control of primary tumours but is less able to eradicate disseminated disease. Theoretically, chemotherapy has the greatest potential in the treatment of disseminated disease because systemically administered drugs can conceivably gain access to the entire body. The Achilles heel of chemotherapy is that its selectivity for cancer cells relies primarily on the fact that malignant cells multiply faster than most normal tissue cells. However, some normal cells, particularly those in the bone marrow and intestines, also divide rapidly and may thus be killed by chemotherapeutic agents, giving rise to toxicities that ultimately limit the effectiveness of treatment. Moreover, to elicit cures, the drugs have to reach and kill essentially all the clonogenic cells in a tumour. This is a formidable task if one considers that even a small tumour deposit, 1 cm3 in size, consists of over 1,000 million cells.
A major cause of treatment failure of both radiotherapy and chemotherapy is a population of tumour cells that is not well served by the tumour vasculature. These cells are hypoxic, are more resistant to treatment and can repopulate the tumour after other cells have been killed. The drugs and technologies developed by Angiogene target this resistant region of solid tumours and thus have the potential to dramatically enhance the effectiveness of both standard chemotherapy and radiotherapy.
Although likely to prove effective against a broad range of solid tumours current efforts are focused primarily on carcinoid and related neuroendocrine malignancies.