A Minneapolis dog is the first to try an experimental treatment that could work on incurable brain tumors in people and dogs.

Batman has always been a hero to Anna and Eric Baker. Not the comic book variety, but a furry, 38-pound, bat-eared one who patiently lets their toddler climb all over him.

Now, if all goes well, he may also become a hero for the thousands of people -- and tens of thousands of dogs -- who each year have brain tumors diagnosed that are equally fatal in both.

Tuesday, Batman was the first patient to get an experimental therapy that researchers at the University of Minnesota hope will cure his brain cancer, which is the same kind that Sen. Ted Kennedy has. If it works for Batman and other dogs, they say, it holds enormous promise as an effective treatment for people, too.

Batman has joined a relatively new field of research called comparative oncology, where researchers leverage what they learn from pets for both animals and people. Advances in molecular and genetic testing show that many diseases in animals don't just look the same in humans, they are the same, said Dr. Jaime Modiano, professor of comparative oncology at the university's veterinary school.

The approach is gaining momentum because testing experimental treatments in animals is also a lot faster and easier than testing them in people. There is no federal regulatory approval process, for one. Since dogs and most other animals don't live as long as humans, both their diseases and treatments progress or fail seven to ten times faster.

That means the Bakers will know within three to seven months, rather than years, whether Tuesday's surgery and the experimental treatment will prevent Batman's cancer from returning.

A hefty vet bill is avoided

The price is right, too. Because it's part of a federally funded cancer research trial, the Bakers are spared a $6,000 to $9,000 vet bill for surgery and painful radiation that might have done their dog as much harm as good.

"He was always the most popular member of our family," said Eric Baker, 45. "Now he's the most popular and the most famous."

"And the one with the best medical care," added Baker's wife, Anna Brailovsky, 37.

She and her husband, who live in Minneapolis, found him while they were graduate students in Berlin, Germany, in 1999. They threw a party. Two hundred people and one bat-eared dog showed up.

He is 10 years old now. Two weeks ago he had a seizure. Then in a matter of days he had two more. A university vet said he might be fine. Or he might have a brain tumor. Only a $1,400 MRI could tell them.

They faced the dilemma that many pet owners confront. Should they spend thousands for diagnostic testing and treatment that might -- or might not -- extend his life a little, but could also make him miserable? Eric Baker is out of work and their debts are piling up.

"Should I let my dog die because I didn't have the money," Anna Brailovsky said. It might be different if Batman was near the end of his life, but he was still lively. "I could no more do that to him than I could for a person," she said.

Then they got a call from Dr. Elizabeth Pluhar, a veterinary neurological surgeon at the university. She had a proposal. If he had a tumor, Batman could be the first of 50 dogs they hope to enroll as part of a federally funded research trial to test a combination of gene therapy and vaccine.

Both are experimental treatments for human types of cancer, but so far neither has proven to work especially well.

Just across town, Dr. John Trusheim is experimenting with a cancer vaccine in people with brain tumors. By coincidence, the first Minnesota patient got his first injection just last week, said Trusheim, a brain cancer specialist at Abbott Northwestern Hospital in Minneapolis.

While vaccines have had limited success on other types of cancer, scientists are eager to try it with brain cancer, Trusheim said.

"We're up against a tumor that has just a miserable prognosis," Trusheim said. Such tumors kill 13,000 people a year and are the leading cause of cancer deaths in children.

Early studies of the human vaccine, called DCVax, showed it slowed tumor progression by several months, he said. But the results of this study, which will involve hundreds of patients nationwide, won't be known for at least two years.

Gene therapy at work

John Ohlfest, head of the neurosurgery gene therapy program at the university's Masonic Cancer Center, is combining a vaccine with what is known as gene therapy. After surgically removing the tumor, the remaining cancer cells are triggered into producing a protein that makes them visible to the body's immune system. A vaccine made from dead brain tumor cells directs the body's immune system to attack and destroy new tumor cells.

Both he and Trusheim say it's the first time a combination therapy has been tried beyond mice, where it has cured them three-fourths of the time, which Ohlfest said is remarkable success.

It would take a decade or more to win approval from the Food and Drug Administration to try the combination therapy in people, Ohlfest said. But dogs are twice as likely as humans to develop such tumors and there's no good effective treatment for them either.

"We will figure out how to treat these animals and tell the FDA we can do it in people," he said.

On Tuesday morning Batman lay on an operating table at the university's hospital for small animals. Anna Brailovsky watched the room packed with animal and human doctors from a window.

"The only thing that stops me from being nervous is that they have so much at stake in keeping him alive," she said.