UPDATE - Issue 03 - June 1999
From Mice to Men
Just a year ago, The New York Times splashed a story across its front page that Bostonian Dr Folkman had demonstrated a drug in laboratory mice which stops malignant tumours. Since then, one of the two drugs he demonstrated has proved too difficult to manufacture and the other, Endostatin, is expected to move to human trials later this year. Folkman first suggested that tumours cannot grow without inducing the growth of new blood vessels back in the 1970s. But it has only been in the past five years that scientists have been able to isolate the cellular mechanisms which control the process.
Behind this media hyped work which led to the Miracle Cure for Cancer just around the Corner type headlines, there are numerous research projects, all of which are following the strategy of looking for treatments which starve tumours by cutting off their blood supply. Growing cells produce chemicals which stimulate the growth of blood vessels, a process known as angiogenesis. With new capillaries and a local blood supply the cells can grow rapidly, which is exactly what we do not want cancer cells to do.
Also with a direct feed into the body's veins, the cancer cells can migrate to new sites and set up secondary growth points, again highly undesirable. Researchers are, therefore, looking for angiogenesis inhibitors. The good news is that they are well along the road to finding a fair number, some of which are now in clinical trials. The current situation is set out in the table.
This shows that there are four drugs which are in large scale controlled trials (Phase III), normally the last phase before requesting approval to market the drug.
Trials of drugs which inhibit blood vessel growth:
| TRIAL STAGE | CANCERS TARGETED | DRUG NAME | COMPANY |
| III | Prostate, Lung | AG3340 | Agouron |
| III | Pancreas, Lung, Breast | Marimasat | British Biotech |
| III | Lung | Neovastat | Aeterna |
| II/III | Prostate, Lung, Breast, Colorectal, Renal | Anti-VEGF antibody | Genentech |
| II (Early trials on efficacy) | Advanced solid tumours | TNP-470 | TAP Pharmaceuticals |
| I (Small scale trials for drug safety) | Solid tumours in children, lymphomas, acute leukaemia | TNP-470 | TAP Pharmaceuticals |
| I/II | Colorectal and others | SU5416 | Sugen |
| I | Advanced cancers | PTK787/ZK | Novartis |
| I | Solid tumours | Endostatin | Entremed |