About a year ago, Sherman, a 13-year-old Pomeranian often mistaken for a teddy bear, had a stroke. The right side of his body went slack, and he couldn’t hear or move his tongue. His owners, Paola Anderson and Sarah Godfrey, had to feed him by hand and carry him outside.
After spending several weeks and thousands of dollars on veterinarians and tests, they discovered the culprit: a tumor in an adrenal gland. Vets said Sherman probably had less than a month to live unless he had a tricky surgery. But Anderson and Godfrey didn’t want to put him through that. Even before the stroke he was a sick dog — with ligament problems, a collapsing trachea, and chronic bronchitis.
They asked a local herbalist who had treated them for years for advice. “He said, whatever you need to do to put your dog on rapamycin, do it,” Anderson told BuzzFeed News.
They had never heard of rapamycin, and started reading everything they could find about this supposed wonder pill. Turns out it’s an old drug, first isolated in the 1970s from dirt samples collected on Easter Island. In large doses, it can be a dangerous drug: Today, it’s usually prescribed to suppress a person’s immune system during an organ transplant.
Rapamycin stops tumor growth in lab experiments, and similar drugs have been tested in people with a variety of cancers. More recently, it’s made headlines for a tantalizing link to longevity: In studies of yeast, worms, flies, and mice, rapamycin has extended lifespan by 15 to 30%.
Most exciting for Anderson and Godfrey, scientists in Seattle had just launched a study to see if rapamycin would also extend the life of older dogs. Sherman couldn’t get into the study because he wasn’t a healthy dog. But he could still try rapamycin — if they could find a vet willing to prescribe it.
Anderson and Godfrey visited eight vets in the Los Angeles area, excitedly explaining all they had learned about the history of rapamycin and the new study in Seattle. Vet after vet turned them down, many dismissing it as a hoax. “Nobody wanted to touch this rapamycin. They didn’t know what it was,” Anderson said.
Then they tried Maria Brömme, an Orange County vet who was intrigued enough to call Matt Kaeberlein, the scientist leading the Seattle trial. He told her that rapamycin research on dogs was still in early stages, but that in low doses rapamycin didn’t seem have many side effects.
“I’ve always been very supportive of owners who want to try different methods — why not?” Brömme told BuzzFeed News. “It’s worth a try, especially in a dog who may ultimately die.”
It’s hard to know how many pet dogs have tried rapamycin, but the number is small. By the end of this year, 160 dogs with bone cancer from all over the U.S. will be taking it as part of a clinical trial. Vets at the University of Tennessee told BuzzFeed News that over the past nine years, they have prescribed it to about 40 dogs with aggressive blood vessel cancer. And 16 healthy middle-aged dogs have now tried rapamycin in the Seattle aging study.
This research is preliminary, but promising: The Tennessee vets say that anecdotally, when given with chemo, rapamycin seems to extend survival, giving dogs 9 to 12 months to live instead of 4 to 6. Kaeberlein’s study in Seattle, although quite small, found that compared to a placebo pill, 10 weeks of rapamycin seems to improve the heart function of healthy older dogs.
“It looks like the effects may be pretty pronounced in dogs,” Kaeberlein told BuzzFeed News, though whether this will lead to a big boost in a dog’s lifespan, as it does in mice, is still very much an open question.
“The good news is, we really didn’t see any significant side effects,” Kaeberlein said. The only notable side effect observed, he said, was increased water consumption, which did not happen in every dog. (Kaeberlein did not put his own dogs, Chloe and Dobby, into the trial because of the conflict of interest.)
As more dog lovers hear about this work, there’s no doubt that some, like Anderson and Godfrey, will convince their vet to give rapamycin to their pup. Veterinarians are allowed to prescribe any human drug they deem appropriate. So as long as its owner pays — and rapamycin isn’t cheap, at about $200 a month for a 45-pound dog — a dog can try the latest trend in anti-aging.
Some vets say this is a terrible idea for healthy dogs, given that no one knows what the best dose is, or whether long-term use comes with side effects.
“I would not put my dog on rapamycin as an anti-aging compound unless I knew a whole lot more about it,” Al Legendre, an emeritus professor of veterinary medicine at the University of Tennessee who has prescribed rapamycin to dogs with aggressive cancer, told BuzzFeed News.
On the other hand, if the next few years of research brings strong evidence of rapamycin’s benefit in dogs, it’s bound to boost the public’s curiosity about the drug — and not only for their pets.
“I suspect a lot of people would start taking it themselves, regardless of what the FDA does or doesn’t approve,” Kaeberlein said. “I think if people see this working in their pets, they’re going to believe at a fundamental level that it’s possible in people.”
More than 1,500 people tried to get their dogs enrolled in Kaeberlein’s rapamycin trial, but only 24 dogs ultimately completed it, all of them at least 6 years old. Of those, 16 got rapamycin three times a week for 10 weeks, and the others a placebo. The owners didn’t know which pill their dog got until the end.
Herb Krohn, whose 10-year-old Chow Chow named Lola participated in the study, noticed a distinct change in her behavior after starting the trial.
“She became increasingly demanding of attention and affection,” Krohn told BuzzFeed News, jumping on his legs more often than usual. “You think to yourself, am I really seeing a change in the drug? Or am I just noticing it because I’m paying more attention to her, looking for the side effects?” He found out later that Lola was indeed on rapamycin.
Susan Smart’s dog, a 10-year-old Soft-Coated Wheaten Terrier named Riley, also received rapamycin in the trial. But Smart didn’t notice any changes in his behavior. Lynn Gemmell noticed that Bella, her 8-year-old Border Collie-Australian Shepherd mix, started pooping twice as often as usual after taking the pill. But she turned out to be on placebo.
Ross Hotchkiss’s dog Zeke, a 9-year-old Boxer-Border Collie mix who’s just starting to go gray, also got a placebo. But Hotchkiss has long been fascinated by the studies of rapamycin and other possible anti-aging drugs, and is sure that some “proselytizers” of the longevity movement will be trying to get rapamycin through their vet.
“For my money that’s a foregone conclusion,” he told BuzzFeed News. That doesn’t mean it’s a good idea, since at the wrong dose rapamycin can lead to serious problems, including opportunistic infections, high blood pressure, or even lymphoma. “How do you use it, and are you sure that it’s safe?” Hotchkiss said. “That’s kind of a Russian roulette.”
As for Sherman the teddy bear, Anderson and Godfrey noticed improvements in his health a couple of weeks after he started rapamycin, almost exactly a year ago. He’s been on it ever since, at a cost of about $21 a week. “He runs like a puppy,” Anderson said. “He goes up and down the stairs like nothing.”
Sherman still has some health issues, including high blood pressure, hearing loss, and the occasional cough. His progress, of course, could have nothing to do with rapamycin. But Brömme, his vet, is impressed, noting that most dogs with his form of cancer don’t survive nearly as long. In April, she said, Sherman’s tumor measured 1.71 centimeters across, no bigger than it was at the start.
“I think it’s amazing that he’s still doing so well after a whole year of getting this diagnosis,” she said.
Anderson and Godfrey were so convinced of rapamycin’s effects that, about six months ago, they started giving it to their other dog, Momo, a 13-year-old Pomeranian-American Eskimo with skin allergies and some mild back problems. They say the drug has improved Momo’s skin, with no side effects so far. “He has boundless energy,” Godfrey said.
Despite their enthusiasm for the drug’s effect on their dogs, the 36- and 37-year-olds say that, for now, it’s too expensive for self-experimentation. “If I was rich,” Anderson said, “I would take it.”
Virginia Hughes is a science editor for BuzzFeed News and is based in New York.
Contact Virginia Hughes at email@example.com.
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