Jack Hoopes patients in an experimental study exploring the efficacy of a new cancer treatment derived from a common plant virus. After receiving the viral therapy, several of the dogs had their tumors disappear entirely and lived into old age without recurring cancer. Given that around 85 percent of dogs with oral cancer will develop a new tumor within a year of radiation therapy, the results were striking. The treatment, Hoopes felt, had the potential to be a breakthrough that could save lives, both human and canine.
Jack Hoopes spends a lot of time with dying dogs. A veterinary radiation specialist at Dartmouth College, Hoopes has spent his decades-long career treating canine cancers with the latest experimental therapies as a pathway for developing human treatments. Recently, many of Hoopes’ furry patients have come to him with a relatively common oral cancer that will almost certainly kill them within a few months if left untreated. Even if the cancer goes into remission after radiation treatment, there’s a very high chance it will soon re-emerge.
“If a treatment works in dog cancer, it has a very good chance of working, at some level, in human patients,” says Hoopes.
The new cancer therapy is based on the cowpea mosaic virus, or CPMV, a pathogen that takes its name from the mottled pattern it creates on the leaves of infected cowpea plants, which are perhaps best known as the source of black-eyed peas. The virus doesn’t replicate in mammals like it does in plants, but as the researchers behind the therapy discovered, it still triggers an immune response that could be the key to more effective treatments for a wide variety of cancers.
The idea is to use the virus to overcome one of the gnarliest problems in oncology: a doctor’s best ally, their patient’s own immune system, doesn’t always recognize a cancerous cell when it sees one. It’s not the body’s fault; cancer cells have properties that trick the immune system into thinking nothing is wrong. Oncologists have puzzled over this for nearly a century, and it’s only in the past decade that researchers have really started to get a grip on cancer’s immunosuppressive properties. Immunotherapy, which has emerged as one of the most promising types of cancer treatment, is all about developing techniques to help the body’s immune system recognize cancerous cells so it can fight back. It’s the medical equivalent of putting a big flashing neon sign on the tumor that reads “ATTACK HERE.” And that’s where the cowpea mosaic virus could help.
Originally published by ARSTechnica