CANCER: Folkman’s Lab Finds Another Anti-Tumor Drug
A year and a half after cancer-fighting proteins endostatin and angiostatin burst into public consciousness, a team of Harvard researchers led by Drs. Judah Folkman and Michael O'Reilly has identified another protein, "antithrombin," that they say helps block blood vessel development among cancerous cells. Findings presented in today's issue of Science indicate that antithrombin, an angiogenesis inhibitor like endostatin and angiostatin, prevents cell growth by inhibiting the supply of oxygen and other nutrients carried by the blood stream to tumor cells (AP/Baltimore Sun, 9/19). Unlike chemotherapy, angiogenesis inhibitors don't poison cells, thereby avoiding unpleasant side effects like nausea and hair loss. But antithrombin may have particular advantages over endostatin and angiostatin: It is relatively easy to reproduce and transport, and biotech firm Genzyme already manufactures a version of the drug for use as an anticlotting agent (AP/Philadelphia Inquirer, 9/17). Genzyme will continue to manufacture antithrombin and doesn't anticipate any delays in arranging human trials for the new protein (Saltus, Boston Globe, 9/17). Several other leading pharmaceutical developers, including Bristol-Myers Squibb and Regeneron Pharmaceuticals, have all but abandoned their efforts to use various forms of endostatin to replicate Folkman's results (Wade, New York Times, 9/17).
Breast Cancer Drug
In other cancer news, the FDA yesterday approved use of epirubicin to help reduce relapse rates in women with breast cancer whose tumors have spread to their lymph nodes. After surgery, about 75,000 women with node-positive, early-stage breast cancer annually require "adjuvant chemotherapy" to kill tumors. Researchers at Pharmacia & Upjohn, which will manufacture epirubicin under the name Ellence, added the drug to one of two common types of chemotherapy known as CMF and found improved survival rates -- 62% for the combination, compared to 53% for CMF alone. Ellence does, however, cause a host of side effects associated with chemotherapy and may induce permanent heart damage or leukemia, the Inquirer reports (9/17). Nonetheless, at least one industry analyst expects sales to hit $150 million annually (Middleton, Wall Street Journal, 9/17). Other breast cancer developments this week:
- The FDA opted not to back Liposome Co.'s version of common chemotherapy drug doxirubicin, marketed as Evacet and used to inhibit the spread of breast cancer, because only one of the company's three trials demonstrated Evacet's efficacy as a first-line treatment (Wall Street Journal, 9/17).
- At the European Cancer Conference in Vienna on Wednesday, Canadian physicians and AstraZeneca, maker of breast cancer preventive tamoxifen, announced preliminary findings supporting estrogen-suppressing drug anastrozole. Known commercially as Arimidex, anastrozole may double the delay in cancer growth seen by patients using tamoxifen (Talaga, Toronto Star, 9/16).