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The Catalyst

New option available for women with breast cancer

by Ashley Barker
Public Relations

A new drug is on the market that has fewer side effects and works better than prior standard treatments for advanced breast cancer patients.

Breast oncologist Dr. Rita Kramer, left, with Caitlin Mengler, R.N., nurse practitioner; Judy Horton, R.N., clinical nurse leader; and Katherine Halloran, R.N., former study coordinator for clinical trials at Hollings Cancer Center.

Breast oncologist Dr. Rita Kramer, left, with Caitlin Mengler, R.N., nurse practitioner; Judy Horton, R.N., clinical nurse leader; and Katherine Halloran, R.N., former study coordinator for clinical trials at Hollings Cancer Center.

The Food and Drug Administration recently approved the use of Kadcyla, which was known as T-DM1 during its development phase, for patients who have HER2-amplified metastatic breast cancer and who have progressed beyond standard therapies.

The "smart" new treatment links a toxin to a monoclonal antibody against the gene HER2 so that HER2-amplified cancer cells are destroyed in a two-stage attack. T-DM1 attaches to the cancer cell and inhibits growth signals through HER2.
Then the drug is internalized and the toxin is released to kill the cancer cell.

T-DM1 delivers a killing agent only to the cancer cells that express HER2, a gene found in 15 - 20 percent of breast cancers, according to Rita Kramer, M.D., breast oncologist and associate professor in the MUSC Division of Hematology and Oncology. Previous treatment strategies involved asking patients to take two different medications at the same time, one targeting HER2 and a second non-targeted chemotherapy.

"T-DM1 patients have less diarrhea, less nausea, less soreness of the mouth and fewer side effects involving the hands and feet turning red, being tender and peeling," Kramer said. "The cytotoxic chemotherapy is going more directly where it needs to go and is better at controlling the patient's disease, shrinking the disease, and extending the duration of time before the disease worsens, which helps the patient live longer."

A clinical trial to research T-DM1, involving 991 patients at 213 centers in 26 countries, was conducted from February 2009 until October 2011. Half of the patients were given T-DM1 and the others received lapatinib and capecitabine, the previous standard of care. One of those patients was at MUSC in the care of the breast medical oncology team at Hollings Cancer Center. The team consisted of Kramer, Neal Christiansen, M.D., and Frank Brescia, M.D.

"You have to be pretty brave to do this. Those women get the therapy, and they let us follow them along. We look at what happens and compare the results of the new drug to the old drug. That's what generates the data that allows the FDA to say this one is better than that one," Kramer said. "MUSC contributed to getting this data. The women who went on the trial contributed to us getting that information."

When someone has metastatic cancer and a cure is not available, Kramer said, the goals are to help the patient feel better and control the disease as long as possible. T-DM1 patients lived longer and lived better.

"That's what this drug does. The patient might respond to one treatment, but then the disease learns to outsmart that drug. They might respond to the second treatment, but the disease will probably outsmart that one, too. So we keep trying different treatments," Kramer said.

Progression-free survival is how long the disease is controlled with the one treatment before the drug must be switched to something else. Results from the trial, published in The New England Journal of Medicine, showed that the median progression-free survival was 9.6 months with T-DM1 versus 6.4 months with the other standard drugs, as assessed by independent review. Investigators also found the median overall survival rate increased from 25.1 months for standard drugs to 30.9 months for T-DM1 users.

"The entire breast cancer team of physicians, nurse practitioners, nurses and clinical trial coordinators at Hollings Cancer Center is committed to improving therapies for their patients through clinical trials. The women who went on that trial made therapy better for all the women who came after them," Kramer said. "We want the therapy to benefit the women who go on the study, but it's also benefitting all the women who come after them with this type of disease."

Kadcyla can cause liver toxicity, heart toxicity, severe life-threatening birth defects and death, according to a warning from the FDA. The most common side effects from Kadcyla reported by patients were nausea, fatigue, pain in the muscles or joints, low levels of platelets in the blood, increased levels of liver enzymes, headache and constipation.

When T-DM1 was in the clinical trial stage it was only available to patients in the study.

Since its FDA approval on Feb. 22, Kadcyla is now an option for advanced HER2-amplified metastatic breast cancer patients and is already in use at MUSC.

"This is our new second-line standard therapy," Kramer said. "We translated this molecular biology finding to a new therapy. We've proven that it works, and now we can just get it off the pharmacy shelf. We're excited because it's a new therapy that works better and has less toxicity. This is a big advance."


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