Cancers in dogs depend on angiogenesis (the creation of new blood vessels) to survive and proliferate. Tumors create new blood vessels that supply them with oxygen and nutrients, allowing them to grow in size and spread throughout the body. Antiangiogenic therapy cuts off these new blood vessels, effectively starving tumors and preventing their growth. Cancers may be controlled with effective doses of antiangiogenic drugs. Angiogenesis inhibitors are designed to attack tumors by depriving cancer cells of their blood Some antiangiogenic drugs may also be combined in order to hit multiple targets and improve their effectiveness.
Antiangiogenic therapy offers a number of advantages over traditional therapies for cancer:
Tumor cells often mutate and become resistant to chemotherapy. Because antiangiogenic drugs only target normal endothelial cells, these cells are less likely develop acquired drug resistance.
All tumors rely upon host vessels. Antiangiogenic agents are therefore effective against a broad range of cancers. Conventional chemotherapy and radiotherapy indiscriminately attacks all dividing cells in the body, leading to side effects such as diarrhea, mouth ulcers, hair loss, and weakened immunity. Antiangiogenic drugs selectively target dividing blood vessels and cause fewer side effects.
Antiangiogenic drugs are relatively nontoxic and work at levels well below the maximum tolerated dose, so may be given in lower doses over longer periods of time.
Antiangiogenic treatment may take weeks or even months to exhibit its full beneficial effect, but this allows for continuous, chronic control
Antiangiogenic drugs may also serve as a powerful supplement to traditional chemotherapy or radiation therapy.