Chemotherapy is brutal: nausea, diarrhea, fatigue, hair loss. The problem, of course, is that the chemicals doctors use to kill cancer cells also destroy healthy cells, wreaking havoc throughout the patient’s body. But what if there were a way to aim the chemotherapy directly at the cancer cells, ignoring the surrounding tissue? That’s the promise of T-DM1, a pioneering new breast cancer drug being tested by Dr. Jenny C. Chang, 49, director of the Houston Methodist Cancer Center and one of the world’s leading oncologists.
The drug works by targeting HER2, a normal protein in epithelial cells that regulates cell growth. About a quarter of breast cancers are HER2+, meaning that the protein is over-expressed, causing cancer cells to divide more rapidly than normal. In 1998, researchers developed an antibody called Herceptin that attaches itself to the HER2 and prevents it from replicating. Chang’s drug, T-DM1, uses Herceptin as a Trojan horse to infiltrate the cancer cell, delivering a highly concentrated dose of chemotherapy—a dose that is 100 to 1,000 times more powerful than the body can normally withstand.
Chang believes that in the future all chemotherapy will be administered in a similar way. “If you can deliver the chemotherapy right into the cancer cells without disturbing the normal cells, then you don’t have any of the toxicity associated with chemotherapy,” she says. “It’s pretty cool.”
For Chang, fighting cancer is personal. As a child in Singapore in the 1970s and ’80s, she watched seven of her relatives, including a 9-year-old cousin, succumb to the disease after repeated rounds of chemotherapy. Chang would grow up to earn an MD from the University of Cambridge and a research doctorate in oncology from the University of London. She worked for a year at Singapore’s National University Hospital before moving to Houston early in the last decade to become an assistant professor at the Baylor College of Medicine. In 2010, Houston Methodist recruited her to direct its cancer center.
The walls in Chang’s corner office overlooking Rice University are filled with framed photographs of Buddhist temples and other exotic locales—photographs that she herself took during what used to be regular trips abroad. Her new job has forced her to curtail the world traveling, however. In addition to her research duties, Chang treats as many patients as a full-time oncologist does. “I don’t sleep very much—it’s called lunacy,” Chang says, laughing.
In February, the FDA approved T-DM1 for the treatment of women with advanced HER2-positive breast cancer. Unfortunately, when breast cancer is that far advanced, T-DM1 can only extend life for a matter of months, so Chang is currently conducting a study to determine T-DM1’s effectiveness against early-stage breast cancer. She plans to present her findings at the San Antonio Breast Cancer Symposium in December and is optimistic about the drug’s potential. “I think in the near future [breast cancer] will become a disease that we can definitely treat very well, and cure the majority of cases,” she says.
HER2 has also been found in stomach and colorectal cancer, so the potential benefits of Chang’s research are massive. Colon cancer is the second leading cause of cancer-related death in the U.S. “We are making definite, incremental steps in beating this disease,” she says. “I think that’s why survival is improving—people are living with cancer.
“There will never be one drug; there will be all these small drugs, but these are significant steps forward.”