In a Phase III trial involving 878 lung cancer patients, the drug bevacizumab, known as Avastin, increased the overall survival rate to 35 percent when combined with the chemotherapy drugs paclitaxel and carboplatin. Patients who were given paclitaxel and carboplatin without Avastin had a 15 percent chance of responding to treatment. Two months ago, the Food and Drug Administration approved Avastin as a first-line treatment for patients with inoperable, locally advanced, recurrent or metastatic non-squamous, non-small cell lung cancer. Avastin works by stopping the formation of blood vessels that feed oxygen and nutrients needed for tumor growth. Because the drug is a targeted therapy, in that it leaves healthy tissue alone while going after cancer cells, some of the traditional side-effects from conventional chemotherapy, such as hair loss, nausea, or vomiting, are avoided.
According to Harold C. Simmons Comprehensive Cancer Center at UT Southwestern Chief of Hematology/Oncology's Dr. Joan Schiller, "Twenty years ago, we thought no treatment could help patients with advanced lung cancer. Ten years ago, we found that chemotherapy could improve survival of these patients. Now, we are finding out that this very unique drug called Avastin can also help improve survival even more. Avastin is the first of this very exciting family of drugs to be approved for lung cancer, and there are several other drugs of this type under development which may prove to work even better."
1. Avastin enjoys good press and proves that Folkman had been on the right track for the past 35 years, that tumors can be effectively controlled by targeting the network of blood vessels that feed them. Tumor growth is dependent on angiogenesis. Angiogenesis is dependent on VEGF. Avastin directly binds to VEGF to directly inhibit angiogenesis. Within 24 hours of VEGF inhibition, endothelial cells have been shown to shrivel, retract, fragment and die by apoptosis. In addition to VEGF, researchers have identified a dozen other activators of angiogenesis, some of which are similar to VEGF.
The drug has won approval from governments all over the world for its success in treating colon cancer. Once that door opened, researchers began trying it on other malignancies. Leonard Appleman has been testing Avastin on kidney cancer patients at Dana-Farber. Harold Burstein, working at the same institute, has been testing it on women with breast cancer. Others are treating ovarian cancer with Avastin.
More and more scientists are finding out that a drug's effect is independent of where the tumor came from in the body. Under current treatment selection methods virtually no chemotherapeutic drug has been successful in more than 50 percent of patients with advanced cancer. But instead of considering a drug that works only ten percent of the time a failure, it would be better to consider such a drug effective for one in ten tumors and to search for the agents among the current arsenal of chemotherapeutic drugs that will work for the rest.
Having a good tumor-drug match not only would improve survival rates, it would be cost-effective, and the high cost of the newer cancer therapies reinforces the necessity of choosing the right therapy the first time around. The tumors of different patients have different responses to chemotherapy. It requires individualized treatment based on testing the individual properties of each patient's cancer.
Posted at 2:14PM on Dec 14th 2006 by Greg Pawelski