NEW YORK (PIX11) — Three-year-old Max is a happy, healthy golden retriever living on Manhattan’s Upper West Side. And thanks to a new cancer treatment that successfully removed a malignant tumor on his paw, he is now cancer free.

In December, Max’s owner noticed a lump on his foot.

“I showed it to the doctor,” said Danielle R’Bibo, Max’s owner. “They assumed it was a little cyst or something. Didn’t think much of it. [The vet] said he was going to do a biopsy. [He] called me a few days later and told me it was a mast cell tumor.”

The tumor was in a difficult spot. Max was expected to lose a few toes and have mobility issues for the rest of his life. But the night before the scheduled surgery, R’Bibo received a call from Max’s veterinarian.

“He called me and said, ‘There’s an alternative. This medicine is called Stelfonta,’” said R’Bibo.

Instead of surgery, Max received a single injection of a new drug called Stelfonta, which is designed to treat mast cell tumors in dogs.

“What’s crazy and unique about this drug is, three to seven days after I inject it into a dog’s mast cell tumor, the tumor falls off,” said veterinary cancer specialist Dr. Sue Ettinger. “And they have an open wound that heals on their own over four to six weeks after the injection.”

Dr. Ettinger is Max’s veterinarian and explained that Max’s tumor posed a particular challenge.

“The hard part about Max’s mast cell tumor is that it was in between two of his toes,” said Dr. Ettinger. “And before Stelfonta was available, we would have had to amputate his two middle toe digits, which are his weight-bearing ones.”

Stelfonta proved successful, and Max is now cancer free. He receives occasional checkups and biopsies to ensure another tumor does not develop.

“I’m very happy,” said R’Bibo. “Because he’s a puppy. My kids love to play with him. He loves to play ball…I just think it would be very sad for him and for all of us if he couldn’t be his playful, jumping self.”