How a Trial Vaccine Helped Wipe Out a Woman’s Breast Cancer in 7 Months

In Clinical Studies News by Barbara Jacoby



  • Florida woman Lee Mercker is recovering well in less than a year after undergoing a new trial vaccine for her breast cancer.
  • Mercker had a very early form of breast cancer and the vaccine was designed to target and kill cancer cells. She was treated at the Mayo Clinic.
  • Cancer doctors and researchers explain how cancer treatment vaccines work and whether or not they could prevent tumors in the future.

A woman in Florida is recovering well just months after undergoing a new trial vaccine for her breast cancer. Lee Mercker was diagnosed with DCIS stage zero, a very early form of breast cancer, in March—news that came as a shock to her. “I was healthy,” she told Fox 35. “That’s why I was mad. I was stunned, and everyone around me was more mad and more stunned.”

Mercker was treated at the Mayo Clinic and given the option to join a new clinical trial for a vaccine that targets and kills cancer cells. “I signed on the dotted line that day,” she said.

As the “very first test subject,” she was given the vaccine as a shot several times over a 12-week period. “They always took your blood, you had a physical, they’d make your shot right there on the spot for you,” Mercker said. “It was three shots, all in a row, alternating arms, four shots, two weeks apart.”

Miraculously, the vaccine worked. Mercker’s tumor shrunk and her immune system started killing the cancer cells. She also underwent a double mastectomy to make sure that the cancer was gone (as the vaccine was just a trial). Her removed tissue will be studied for further results and to better understand how the vaccine worked. Seven months after she was first diagnosed, she’s healthy again—thanks to a shot.

“I feel like I walked on the moon,” she said. “I worked in an industry with tons of women and I saw all kinds of stories, and it’d just be really nice to stamp this [breast cancer] out.”

Her doctor, Mayo Clinic researcher Keith L. Knutson, PhD, says the drug still has a long way to go, but that the results are very promising. “It is reasonable to say that we could have a vaccine within eight years that may be available to patients through their pharmacy or their doctor,” he said in a recent interview.

How is it possible for a vaccine to kill cancer?

It’s a form of cancer treatment called immunotherapy, explains Pravin Kaumaya, PhD, a cancer vaccine researcher at The Ohio State University Wexner Medical Center. “It is possible to target cancer with a vaccine,” he says. “This is what immunotherapy is all about.”

While there are several types of immunotherapy, treatment vaccines specifically stimulate the body’s immune system to target and kill cancer cells. Basically, these vaccines help your immune system recognize abnormal tumor-related substances, and then destroy the the cancer cells that harbor them, per the National Cancer Institute. They’re currently designed to be used in people who already have cancer.

Dr. Kaumaya actually has a vaccine of his own that’s currently in clinical trial—and there are vaccines like this being developed all over the country. “It’s seemingly happening everywhere and with every type of cancer,” says Jack Jacoub, MD, a medical oncologist and medical director of MemorialCare Cancer Institute at Orange Coast Medical Center in Fountain Valley, Calif. “Doctors are looking to wake up a person’s immune system to attack the cancer, avoiding all of the problems with traditional treatments.”

Could treatment vaccines prevent cancer in healthy people?

While these vaccines are currently in development, it’s very likely that they will eventually work for people who don’t have cancer, too, Dr. Kaumaya says. “It can be both preventive and therapeutic. In patients with cancer, the vaccine targets the cancer cells and then kills them,” he says. “In people who don’t have cancer, the vaccine could activate certain cells, develop antibodies, and then prevent a tumor from growing.”

Overall, Dr. Jacoub says it’s an exciting time for cancer research. “We’re trying to deescalate traditional cancer therapy,” he says. “As these trials advance, the hope is that these vaccines will become available for anyone.”

Dr. Knutson and his team have now started testing the vaccine in two more patients and are looking for others to participate in the trial, per Fox 35. “Really, a vaccine against breast cancer and I think it’s only a matter of time myself,” he said.