A new method of attacking cancer cells, developed by researchers in Australia, has proved surprisingly effective in animal tests.The method is intended to sidestep two major drawbacks of standard chemotherapy: the treatment's lack of specificity and the fact that cancer cells often develop resistance to treatment.

The new method, called EnGeneIC, uses “minicells” to deliver a variety of agents to tumor cells, including both anti-cancer toxins and mechanisms for suppressing the genes that make tumors resistant to toxins.The “minicells” are generated from mutant bacteria which, each time they divide, pinch off small bubbles of cell membrane. The “minicells” can be loaded with chemicals and coated with antibodies that direct them toward tumor cells.No tumor cell, so far as is known, produces a specific surface molecule for toxins to act on. But 80 percent of solid tumors have their cell surfaces studded with extra-large amounts of the receptor for a particular hormone, known as epidermal growth factor.The “minicells” can be coated with an antibody that recognizes the receptor for epidermal growth factor, so they are more likely to attach themselves to tumors than to the normal cells of the body. The tumor cells engulf and destroy the “minicells”, a standard defense against bacteria, and in doing so are exposed to whatever cargo the “minicells” carry.

In one surprisingly effective test of the method, reported online Sunday in Nature Biotechnology, mice were implanted with a human uterine tumor that was highly aggressive and resistant to many drugs. All of the treated animals were free of tumor cells after 70 days of treatment; the untreated mice were dead after a month.

Dr. Robert M. Hoffman, of the University of California, San Diego, said that the “minicells” were "good strategy and good science" but that the researchers had implanted the human tumors under the mice's skin, a position from which they do not usually spread through the body. So the experiments do not answer the question of whether “minicells” can attack metastasized cancer, he said.

For more information, see the article in the St. Louis Post-Dispatch at:
http://www.stltoday.com/stltoday/news/stories.nsf/nation/story/06651E9B82F1DE8C862575E400075F53?OpenDocument

Labels: animal, cancer, chemotherapy, ENGENEIC, minicells, tumor

The FDA announced today that it has approved the first cancer drug specifically to be used for dogs. The drug is called Palladia and is manufactured by Pfizer. The drug is used to treat skin based mast tumors. This type of tumor accounts for 20% of all skin based cancers in dogs. While many mast tumors can appear to be small and benign, they can be a deadly form of cancer in dogs. Some mast tumors can be removed very easily, but some cannot and can cause serious problems. Palladia works in two ways to attack mast tumors: it cuts off the blood supply to the tumor and it kills the tumor.

Until the development and approval of Palladia, all cancer drugs used in veterinary medicine were developed for use in humans and were used in an “extra-label” manner to treat cancer in dogs. When asked for her reaction to the approval of Palladia, DVM and PhD Bernadette Dunham said, “This cancer drug approval for dogs is an important step forward for veterinary medicine. Prior to this approval, veterinarians had to rely on human oncology drugs, without knowledge of how safe or effective they would be for dogs. Today’s approval offers dog owners, in consultation with their veterinarian, an option for treatment of their dog’s cancer.” Some common side effects of Palladia are diarrhea, decrease in or loss of appetite, lameness, weight loss, and blood in the stool.

For more information on Palladia, see the approval summary at:
http://www.fda.gov/downloads/AnimalVeterinary/Products/ApprovedAnimalDrugProducts/FOIADrugSummaries/UCM164091.pdf

See the news article on the FDA website at:
http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm164118.htm

Labels: animal, cancer, dog, DVM, FDA, Palladia, Pfizer, tumor, vet