A targeted drug shown to improve the outcome of certain breast cancer patients may be of use in the treatment of advanced cases of bladder cancer, according to new research led by the University of Michigan Comprehensive Cancer Center.
Researchers investigated the role of the protein HER2 - which has been associated with more aggressive breast cancers - in bladder cancer that has metastasized, or spread to other parts of the body. More than half of bladder cancer patients in this study had high levels of the HER2 protein. Recently reported research found the targeted drug Herceptin given along with chemotherapy to women with HER2-positive breast cancer cut the risk of recurrence in half. Here, researchers found Herceptin may also play a role in treating HER2-postive bladder cancer.
"The model for Herceptin is breast cancer. While we are still in the beginning, I think this trial provides an approach for metastatic bladder cancer that has not been previously explored. This opens up the possibility of targeted therapies for bladder cancer," says Maha Hussain, M.D., professor of internal medicine and urology at the U-M Medical School. Hussain presented the findings Saturday, May 14, at the American Society of Clinical Oncology annual meeting in Orlando, Fla.
This multicenter trial is one of the first efforts in which researchers have looked at using targeted therapy in bladder cancer based on the presence of the specific target. Targeted therapies such as Herceptin, which are designed to seek out specific molecules known to play a role in cancer development or growth, tend to be less toxic for patients because they do not harm normal cells, unlike traditional chemotherapy drugs.
In this study of 113 people with bladder cancer, 52 percent were determined to be HER2-positive. The HER2-positive patients were more likely to have cancer in their liver, bones and lungs than those with HER2-negative tumors, and the tumors had spread to more organs than in people whose cancer was HER2-negative, suggesting a more aggressive type of cancer.
The HER2-positive study participants were given Herceptin along with standard chemotherapy drugs used to treat bladder cancer. Patients received on average six cycles of chemotherapy and Herceptin.
Researchers found 70 percent of patients responded to the chemotherapy and Herceptin treatment and saw their tumors shrink. Only 7 percent saw their cancer progress, or worsen. Patients lived an average of 15 months, comparable to overall survival rates for advanced bladder cancer. But, Hussain points out, the patients participating in this study had a more aggressive disease.
"There was a tendency for these patients to have worse disease - more sites of involvement with metastasis, and more bone and liver disease, which is one of the very poor features of bladder cancer in general. We were quite encouraged to see in this study good responses to treatment. This lays the foundation for a future phase III trial to compare Herceptin and chemotherapy to standard chemotherapy," Hussain says.
This phase II trial found Herceptin could be used safely for bladder cancer with few serious adverse effects related to Herceptin. The most common problems were low blood counts.
Bladder cancer affects more than 63,000 people each year and causes about 13,000 deaths per year. It strikes men three times as often as women.
In addition to Hussain, U-M study authors were research associate Rodney Dunn and David C. Smith, M.D., associate professor of internal medicine and urology and medical director of the Multidisciplinary Urologic Oncology Clinic. Other study authors were Daniel Petrylak, M.D., Columbia University; Ulka Vaishampayan, M.D., Wayne State University; Primo N. Lara Jr., M.D., University of California-Davis; Gurkamal Chatta, M.D., University of Pittsburgh; David Nanus, M.D., Cornell University; L. Michael Glode, M.D., University of Colorado; Donald Trump, M.D., Roswell Park Cancer Institute; and Helen Chen, M.D., National Cancer Institute.