And VEGF-Trap seemed to cause fewer bowel perforations, a big problem in the earlier Avastin study.
Lab evidence indicates that an overactive EGF system may help tumors produce more VEGF.
Pharmacia also still thinks VEGF makes a promising target, the company said in a press release.
Nor did many see the halted trial as a failure for the VEGF approach.
While Sugen targeted the receptor for VEGF, Genentech was focusing on the protein itself.
The more VEGF a tumor produces, the faster your cancer grows--and the sooner you die.
Some of them may prove to be more potent growth-stimulants for the tumor than VEGF ever was.
By 1993 the company had designed a monoclonal antibody to VEGF that slowed tumor growth in animals.
But instead of targeting the growth factor, it blocks the receptor by which it VEGF attaches to cells.
"This is a long-term quest, and we can't assume that blocking VEGF alone will be enough, " he says.
Sugen set out to find a druglike chemical that could to turn off the VEGF receptor in humans.
The VEGF gene is so-called because it controls production of a substance known as vascular endothelial growth factor.
After 28 days, glucose levels returned to normal in diabetic mice that received the VEGF implants through the intestine.
Avastin works by inhibiting a protein called the vascular endothelial growth factor (VEGF).
The more VEGF a tumor contains, the more it is likely to grow.
The VEGF approach seems more likely to pay off in the near term.
Doses of the VEGF gene were injected into four places in the heart.
"I don't think this has anything to do with the VEGF target, " says Brian Rye, an analyst at Raymond James.
In the late 1980s Genentech scientist Napoleone Ferrara had isolated the gene for producing VEGF(genes are instructions for manufacturing proteins).
By blocking a protein called the vascular endothelial growth factor (VEGF), it prevents arteries from growing around tumors, literally starving them.
Results from a VEGF pill being developed by Novartis (nyse: NVS - news - people ), however, were disappointing.
It does hit a specific molecular target in the cell called VEGF.
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To the scientists' surprise, the prolonged release of VEGF achieved that result.
Both Sugen and Genentech are rushing to conduct final-stage human testing of drugs that block the action of a key protein, called VEGF.
Instead of turning off VEGF receptors as Sugen's drug does, Genentech's antibody latches onto VEGF itself to stop it from docking with a receptor.
His lab showed this protein to be the receptor for VEGF, and that blocking the receptor stunted the growth of tumors in lab animals.
In addition to Sugen and Genentech, research powerhouses Novartis and AstraZeneca and biotech boutique ImClone Systems are rushing to test new drugs as VEGF-blockers.
By turning VEGF off, scientists hope to starve tumors to death.
One theory, which may explain its failure against breast cancer, is that there may be tissue-specific proteins that spur tumor growth in the absence of VEGF.
He realized, five years before Harvard's Folkman would discover angiostatin, that blocking VEGF with a specially tailored drug might lead to a totally new type of cancer therapy.
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