[Tumor angiogenesis inhibitors: media and scientific aspects].

Work begun more than 30 years ago at Children's Hospital in Boston led to the publication of an article on the antiangiogenic properties of two compounds, endostatin and angiostatin (J. Folkman, Nature 1997; 390:404-7). It only took weeks for the medias in the US and then in France and the rest of Europe to stimulate the fervor of patients for this new 'cure' for cancer. Insight into the fundamental role of angiogenesis in locoregional and metastatic development of cancer has been accumulated over the last decades. Factors stimulating tumoral angiogenesis include aFGF, bFGF, VEGF, angiogenin, and other more recently discovered substances. Likewise, factors inhibiting tumoral angiogenesis, including angiostatin, have been identified. Angiostatin is a specific inhibitor of endothelial cell growth that migh appear rapidly in the serum of patients with a primary tumor. Angiostatin could have both local and systemic effects and possibly protect against metastatic dissemination in vivo. The importance of angiogenesis inhibitors was emphasized at the recent meeting of the American Association for Cancer Research (New Orleans March 28-April 1, 1998). To date, at least eleven compounds are being tested. Currently, most are in phase 1 or 2; for the few in phase 3, marketing approval will undoubtedly require several years. It is interesting to note that neither endostatin nor angiostatin are among the list of drugs under clinical assessment, first because these small human proteins are not available in sufficient quantity for therapeutic trials and secondly, because the processes necessary to produce pure and safe compounds remain to be developed. Even after these steps have been accomplished, preclinical evaluations will have to be performed before the first clinical trials could be envisaged. For the time being, antiangiogenesis remains a promising avenue of anti-cancer research but neither endostatin nor angiostatin will be available for human research for several months at least.