News You Can Use
Cancer Drugs Gain FDA Approval
A Herceptin Alternative
The first newly approved drug, Tykerb (lapatinib), is designed for the approximately 25 percent of patients whose cancer is Her-2-positive. The drug works by interfering with cell communication, depriving cancer cells of the signals they need to grow. Taken in combination with Xeloda, it’s used for women who have locally advanced or metastatic breast cancer and who have already been treated with Herceptin and other drugs. Additional studies are currently comparing Tykerb to Herceptin in two different ways: as a treatment given prior to another therapy (neoadjuvant) or as a treatment given along with a second therapy (adjuvant).
The Tykerb-Xeloda combination also has some ability to shrink brain tumors that have grown following radiation. Hope Rugo, M.D., clinical professor of medicine and director of the Breast Oncology Clinical Trials Program at the University of California, San Francisco, Helen Diller Family Comprehensive Cancer Center, says, “Patients receiving Tykerb and Xeloda had fewer brain metastases compared to women receiving Xeloda alone.” In another study reported at the 2007 San Antonio Breast Cancer Symposium, Tykerb plus Xeloda proved useful as a treatment for brain metastases, with 60 percent of patients experiencing reduction of tumor size.
A Triple-Negative Treatment
One of the most difficult forms of breast cancer to treat is triple-negative metastatic disease. Tumors in this category are negative for estrogen receptors, progesterone receptors and Her-2. The second FDA-approved drug, Ixempra (ixabepilone), could give patients with this type of cancer reason to hope.
Rugo was involved in a multi-center trial in which Ixempra and Xeloda were given to triple-negative patients whose cancer was resistant to chemotherapy. Their overall response rate was three times higher than that of patients who were given only Xeloda (27 percent vs. 9 percent). The combo also lengthened the median progression-free survival rate in this very high-risk group (4.1 months vs. 2.1 months with Xeloda alone).
Ixempra is also being used in a combination form to help women with Her-2-positive breast cancer. A study presented in San Antonio reported complete or partial responses in 24 of 59 patients who took Herceptin along with weekly doses of Ixempra and carboplatin.
Blocking Blood Vessels
Cancer can’t grow without a blood supply, and fast-growing cancers are especially reliant on blood vessels to survive. The drug Avastin (bevacizumab), newly approved by the FDA, works by inhibiting the growth of new blood vessels, and has been shown to improve the survival rate in women with advanced Her-2-negative breast cancer who have not had chemotherapy. “Doctors finally have an answer when a Her-2-negative patient asks, ‘What do you have for me?’ “ says Kathy Miller, M.D., associate professor at the Indiana University Simon Cancer Center.
Miller led the E2100 trial of Avastin, which studied women with metastatic breast cancer who hadn’t yet received chemotherapy. One group received the chemo drug Taxol alone, while another group was given Avastin as well. The second group showed twice the rate of survival without progression to a more advanced stage (11.8 months vs. 5.8 months). “Better progression-free survival means women had an extra six months during which their disease was under control. It means feeling as well as possible for as long as possible,” says Miller. Studies are now underway to measure Avastin’s effect as part of therapy for patients with newly diagnosed breast cancer that hasn’t metastasized. Miller says the future should hold more drugs which, like Avastin, are “hopefully more effective” than current therapies.
Coming Soon?
A drug now in trials may get the green light for use against breast cancer as well. Sutent (sunitinib) is already approved for treating kidney and gastrointestinal tumors. Like Avastin, it works by blocking new blood vessels from forming.
Luca Gianni, M.D., director of medical oncology at the Istituto Nazionale Tumori in Milan, Italy, studied women with locally recurrent or metastatic breast cancer who had relapsed after chemotherapy. After taking Sutent in combination with the chemo drug docetaxel, 13 of 18 showed a partial response, and nine experienced a decrease in tumor size after two cycles of treatment. Gianni says that in addition to cutting off the blood supply, “sunitinib increases the amount of chemotherapy drugs that reach the tumor.”
Before doing a large-scale study, the researchers wanted to be sure that the drug didn’t elevate the concentration levels of docetaxel in the patients’ blood. It didn’t in this trial, but most patients did experience a drop in white blood cell counts (neutropenia). Gianni explains, “Sunitinib may have contributed to the usual high level of neutropenia already caused by docetaxel.”
Gianni reports that studies of Sutent are continuing in various types and stages of cancer, including previously treated metastatic breast cancer.
