Triple-negative breast cancer accounts for 10 to 15 percent of the nearly 200,000 cases of breast cancer diagnosed in the United States each year. It is an aggressive type of breast cancer that doesn’t respond well to targeted drugs commonly used to treat the majority of breast cancers. But a new class of drugs called PARP inhibitors – the first targeted therapy for triple negative breast cancer – is making inroads in this tough-to-treat breast cancer.
The Phase III clinical trial under way at WVU’s Cancer Center involves combining two standard chemotherapy drugs (gemcitabine and carboplatin) with a PARP inhibitor called BSI-201, or iniparib.
“Iniparib is the best known PARP inhibitor and is the furthest along in being clinically developed,” said Jame Abraham, M.D. , director of the Comprehensive Breast Cancer Program at WVU. “Early data on the drug is very exciting. It’s been shown to have excellent antitumor activity in patients with triple negative breast cancer, and those enrolled in the study at WVU are seeing similar results.”
Teresa Stevens of Fairmont, who’s 60 years old, was diagnosed with late stage triple-negative breast cancer in 2006. She enrolled in the Phase III clinical study at WVU last year after learning that her cancer had spread to her lung and brain.
“Eight weeks into treatment my tumors began shrinking, and they continue to shrink,” Stevens said. “This drug gives me hope. I feel relief and believe I am going in the right direction.”
Beth Ujhelyi of Boothsville, who’s 37, is another hopeful patient. She was diagnosed with triple-negative breast cancer in 2008 and enrolled in the research study this January after the cancer spread to her lungs.
“I am a firm believer that this is the right treatment for my type of cancer,” Ujhelyi said. “After six weeks, my cancer was 90 percent gone. I was in shock. When Dr. Abraham showed me my scan results, I cried, and the nursing staff cried with me. After an additional six weeks of treatment, there was no sign of metastatic disease. That is miraculous to me.”
Dr. Abraham said PARP inhibitors are different from other treatments. “Unlike most targeted therapies for breast cancer, PARP inhibitors do not single out specific hormone receptors or the human epidermal growth factor receptor (HER2),” Abraham said. “These drugs work by targeting the tumor’s DNA preventing it from repairing itself so it can grow and spread. PARP inhibitors actually help standard chemotherapy work better.”
BSI-201 is being developed by the pharmaceutical company BiPar Sciences, a wholly-owned subsidiary of Sanofi Aventis. The company is also studying the new therapy to treat other cancers including lung, ovarian, uterine, brain and pancreatic.
For information on the PARP inhibitor trial at the Mary Babb Randolph Cancer Center see http://oncore.hsc.wvu.edu/sip/SIPControlServlet.
For information on the clinical development of BSI-201 see www.biparsciences.com/000014.html.
CONTACT: Amy Johns, HSC News Service