Persons with non-small cell lung cancer that has spread from the lung to other parts of the body often receive a chemotherapy combination to alleviate the symptoms of disease and prolong survival time. Now, a novel new drug, called tirapazamine, appears to enhance the activity of the chemotherapy drug cisplatin against this disease, according to the recent findings of 1 international study group.
Non-small cell lung cancer (NSCLC) is a term used to describe several types of lung cancer, including epidermoid or squamous carcinoma, adenocarcinoma, large cell carcinoma, adenosquamous carcinoma, and undifferentiated carcinoma. Treatment options for NSCLC may include surgery, radiation therapy, and/or chemotherapy, depending on the
stage of the cancer (extent of disease at diagnosis). Stage IV NSCLC is cancer that originated in the lung and then spread to other parts of the body (called
metastatic disease). Several chemotherapy combinations may be used to treat persons with this type of disease, with 2 of the most effective regimens being cisplatin/etoposide and cisplatin/paclitaxel. However, researchers continue to develop and study new chemotherapy drugs with the hope of providing more effective treatment options.
One of the new drugs that is showing promise is
tirapazamine. Some persons with cancer have lower than normal oxygen concentrations (called
hypoxia) in the body tissues, including in some of the cancer cells. Cancer cells that have low oxygen levels often become resistant to radiation therapy and chemotherapy drugs, making the disease more difficult to treat. Tirapazamine is a drug that is not active against cells with normal oxygen concentrations, but kills cells that are poorly oxygenated. Because this process results in the elimination of the cancer cells that are resistant to treatment, it is believed that the use of tirapazamine with standard anticancer chemotherapy drugs and/or radiation therapy may be effective.
Researchers from several hospitals in the United States and Europe conducted a clinical study to determine the effectiveness of cisplatin with tirapazamine in persons with advanced or metastatic NSCLC. A total of 446 patients were assigned to receive either cisplatin alone or cisplatin with tirapazamine. The response rate was almost 28% in patients receiving cisplatin and tirapazamine, compared with 14% in patients receiving cisplatin alone. The average survival time was almost 35 weeks in patients receiving tirapazamine, and 28 weeks in those receiving cisplatin alone.
The researchers concluded that tirapazamine enhances the activity of cisplatin in patients with advanced or metastatic NSCLC. Since the most active drugs against NSCLC include cisplatin, paclitaxel, docetaxel, etoposide, and
Gemzar® future clinical studies will likely evaluate the effectiveness of combination chemotherapy regimens in combination with tirapazamine. Persons who have metastatic NSCLC may wish to talk with their doctor about the risks and benefits of participating in clinical trials evaluating chemotherapy with tirapazamine or participating in other clinical trials in which promising new treatments are being studied. Two sources of information on ongoing clinical trials that can be discussed with a doctor include a comprehensive, easy-to-use service provided by the National Cancer Institute (cancer.gov) and the Clinical Trials section and service offered by Cancer Consultants.com (www.411cancer.com). (Journal of Clinical Oncology, Vol 18, No 6, pp 1351-1359, 2000)