WSVN — When 38-year-old Heather Hotaling first got the news she had an aggressive breast cancer, her first concern was her children.

Heather Hotaling: "I was OK until I was told I had stage four, and I wasn't curable any more because it really scared me. Here I was, I had two kids and I thought I was gonna die. It was very hard.

The young mother has been on several drugs to stop the cancer, but many of the side effects were rough and she was running out of options.

Heather Hotaling: "I knew for three days I would be in bed just because of the joint pain, just having a low grade fever, feeling like I had the flu."

Fortunately, Heather was able to join a study at the Sylvester Comprehensive Cancer Center for a new chemotherapy drug called Kadcyla.

The drug has just been FDA approved for the treatment of HER2-positive metastatic breast cancer.

Dr. Reshma Mahtani: "HER2 is a gene. What happens in HER2-positive breast cancer is that you receive too many copies of the gene and it changes the function of the gene into a cancer-causing gene and it becomes more aggressive."

Kadcyla is given intravenously to patients every three weeks, but unlike traditional chemo, it spares the normal, healthy cells and only targets the cancer.

Dr. Reshma Mahtani: "It's been called a 'smart bomb'. Because the way that it works is that it's chemo that is linked to a targeted agent that actually brings the chemo right to the cancer cells. And once it's taken up by the cancer cells, the cell is destroyed."

Heather Hotaling: "I'm responding to it, my tumors have shrunk down quite a bit."

And while it's killing the cancer.

Dr. Reshma Mahtani: "Patients are spared a lot of the toxic side effects that we associate with chemotherapy."

For Heather, it's given her more quality time with her family.

Heather Hotaling: "I'm not in bed for three or four days at a time. I think it's a great opportunity to have a great chance to have chemo that isn't completely debilitating and much more doable than the drugs out there."

Alexis Rivera: "In the study, patients also lived about six months longer extra time that can mean so much to families."

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