2018-09-05 / Columnists

Pets, Pets, Pets

Progress in canine cancer therapies can lead to improved therapeutics for people. A new treatment for dogs with the same brain cancer that killed Senator John McCain last month is showing great promise for canine patients. So much so that the National Institutes of Health (NIH) recently awarded a generous grant to the two collaborators: a veterinary school and a medical center.

Sen. McCain had glioblastoma, a very deadly brain cancer. So did Sen. Ted Kennedy and Beau Biden. This aggressive and difficult to treat brain cancer kills half of the people diagnosed within a year. Only three percent survive over three years. The canine prognosis is worse. Dogs get glioblastomas too, but only survive a few months (the average is two months).

In people, glioblastomas are the most common malignant brain tumors in adults, seen more in men than women. These tumors are fast growing and likely to spread. Their cause is unknown but may be related to genetics. Treatment is usually surgery, followed by a combination of radiation and chemotherapy.

Emily, a Portuguese Water Dog, gets clinical trial injection for brain cancer at Virginia Tech. photo credit CBS Emily, a Portuguese Water Dog, gets clinical trial injection for brain cancer at Virginia Tech. photo credit CBS It can be difficult to remove all of the tumor since glioblastomas have tendrils that extend to other regions of the brain. Glioblastomas are often resistant to treatment as they are usually made up of different types of cells. Medication kills off some cells and not others. With glioblastoma in people and dogs, this insidious cancer ‘learns’ which types of cells are immune to the drugs, reproducing these cells more prolifically.

In pets, brain tumors in general are more common in dogs than cats, especially dogs over five years of age. Seizures, behavioral changes, vision problems, vertigo and circling are common abnormalities observed by owners of dogs with brain tumors. Brachycephalic (short-nosed) breeds such as the Boxer, Pug, Boston Terrier and Bulldog have 25 times the normal occurrence for brain tumors, including glioblastomas.

Kya, a 6-year-old Afghan Hound succumbed to brain cancer this summer. Kya, a 6-year-old Afghan Hound succumbed to brain cancer this summer. There can be little warning of the lurking tumor. In June, literally hours after transferring records and telling her new animal hospital that Kya, was “healthy as a horse,” my friend Susan’s six-year-old Afghan began having non-stop seizures in the middle of the night. Next day Kya was diagnosed with an inoperable brain tumor at the specialty hospital. Kya enjoyed a certain quality of life with prednisone and seizure meds until the seizures returned full blast in August. We haven’t confirmed the type of brain cancer with her neurologist yet but narrow skull breeds like Afghans are more apt to succumb to meningiomas, a cancer of the membrane that coats the brain.

The canine clinical trial based out of Virginia-Maryland College of Veterinary Medicine at Virginia Tech has extended the lives of participating, glioblastoma dogs. A new chemo injection being developed and tested in dogs by Wake Forest University in North Carolina and Virginia Tech, seems to “cover” and attack all of the cancer’s cells - a potential breakthrough for animals and humans alike. Researchers from these two medical facilities are hoping to improve survival statistics by slowing growth or even shrinking the tumors in dogs and, ultimately, humans.

The trial’s early tests showed so much promise that the NIH awarded a $9.2 million grant to be used over five years to collaborators at Virginia Tech and Wake Forest Baptist Medical in the hopes that they could continue to fine tune a treatment that might one day save human lives too.

As of August 2018, 12 dogs have participated in the ongoing trial. Some of the funding from the NIH will be used to extend a new round of trials this year. The grant will fund four approaches to treating glioblastoma in dogs.

One method uses a tiny, targeted blast of energy to destroy the membranes of only the cancerous cells. Another group of scientists has been developing an extremely fine “micro-needle device” (catheter) to inject chemotherapy directly into a tumor without damaging other tissues. A third part of the research is working on finding the direct route¬≠— and right vehicle to follow it—from the blood straight to the brain.

The last research group is working on a drug that attacks the most worrisome types of cells in this complex cancer. Portions of the tumor can quickly become treatment resistant. The tumor has evolved ways to identify its toughest cells and divert energy to the replication of those, while letting the easier-to-target cells die off. In the most recent trials—still recruiting and being conducted in dogs—this last treatment has proven to be the key to fighting back against glioblastoma. The first drug the researchers used targeted two types of cells. They have since identified two additional markers, so the newer drug tries to “grab” four potent proteins and stop their growth.

Laura Kamienski of Florida was devastated when she learned her Portuguese Water Dog, Emily, had the deadly cancer. The best treatments available at local specialists were going to cost $10,000 and probably wouldn’t give Emily much more time. Laura enrolled Emily in the Virginia Tech clinical trial, so her dog could get this new injection. The drug is delivered directly to the dog’s tumor through a specialized catheter and infused slowly over several hours. During the last six weeks, Laura watched MRI scans as Emily’s tumor shrinks. The veterinarians at Virginia Tech monitor the tumor using MRI as they treat it.

“We can watch the drug cover the tumor. And so we know we’ve achieved the treatment goals of actually targeting all the cancer cells,” Dr. John Rossmeisl, professor of Neurology and Neurosurgery at Virginia Tech told reporters. Emily has stopped having seizures at home. “The only way this could have been better is if it was totally gone. This is really good news,’ Dr. Rossmeisl said.

The goal of the study is to improve the lives of dogs with brain cancer and later use the canine tumor model to develop novel therapies for humans with this type of brain cancer. Since the trial began, treated dogs have fared better than controls. Dr. Rossmeisl said some tumors shrank, and some dogs lived a year longer than expected.

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