BOSTON (CBS) – A new vaccine is giving hope to patients with one of the most dangerous cancers.

“I’m so lucky. I feel very lucky.”

It’s hard to believe how Margaret Kruse, a mother of four, could possibly feel lucky when last fall doctors gave her the diagnosis of brain cancer, glioblastoma. It’s aggressive and usually fatal within months.

“The prognosis is not good,’ says Mike Farkas, Margaret’s fiancé. “So we were looking for some hope, and the vaccine is that hope.”

That vaccine is why Margaret feels so lucky. She is 1 of 15 people currently enrolled in phase two of a clinical trial testing whether the medication can eliminate her cancer.

“I think this is the most promising of the leads that we’ve had over the years,” says Dr. Robert Fenstermaker, a neurosurgeon at Roswell Park Cancer Institute.

The vaccine called SurVaxM is considered a “next generation” treatment for brain cancer, designed to stimulate a patient’s own immune system to essentially hunt down tumor cells and kill them.

“We wanted to target a protein that was important to brain tumor cells and cancer cells so we looked for one that was over expressed, which means it’s a flag on a tumor cell. It’s like, ‘Hey here I am. Come target me,’” explains Michael Ciesielski, PhD, a researcher at Roswell Park Cancer Institute.

So far, one patient has survived 4 years and scientists are cautiously optimistic.

“I think that this is something that has given me much more hope than anything I’ve worked on in the past,” says Dr. Fenstermaker.

“It would be one of the greatest feelings ever to actually see something that we’ve created in the lab to treat a patient. Give them a greater quality of life and some hope,” says Ciesielski.

And that’s what they have given Margaret–hope on behalf of all of those with glioblastoma.

“They can learn from my experience, you know, and hopefully help other people,” says Margaret.

The trial will take a few more years to complete before doctors know whether SurVaxM is, in fact, better than current treatment options.