Study shows pancreatic cancer drug may fail

By Michael Kahn

LONDON (Reuters) - A poor network of blood vessels may explain why some people with pancreatic cancer are often resistant to a common chemotherapy treatment, international researchers said on Thursday.

A study by Cancer Research UK found that pancreatic cancer can spread quickly to a tumor, despite a healthy blood supply, and gave evidence why conventional cancer treatments such as Eli Lilly and Co's Gemzar were often ineffective.

The study found that combining cancer treatment Gemzar with Infinity Pharmaceutical's experimental drug IPI-926 made the treatment work better in mice with pancreatic cancer.

The findings could lead to better ways to treat one of the most deadly cancers -- one that only three percent of patients survive for five years or more, said David Tuveson, a researcher at Cancer UK's Cambridge Research Institute, who worked on the study.

"We're extremely excited by these results as they may help explain the disappointing response that many pancreatic cancer patients receive from chemotherapy drugs," Tuveson said in a statement.

"But these are early days and we need to show this approach is safe to use in humans before we can consider adding the new compound to cancer treatments," Tuveson said.

Pancreatic cancer is diagnosed in 230,000 people across the world each year, with 7,600 new cases in Britain and 37,000 new cases in the United States, according to Cancer Research UK.

It often spreads quickly and is not detected in many people until it is in an advanced stage, when surgical removal is not possible.

Using genetically engineered mice that develop pancreatic cancer, the researchers found the tumors in the animals were only sparsely threaded with blood vessels -- something they also saw in humans.

This indicated it was harder for drugs to reach the tumor and may help explain why pancreatic cancer does not respond to so-called VEGF inhibitors -- a new class of drugs that starve the tumor by restricting blood supply, the journal Science said.

Because the findings suggest pancreatic cancers do not need as good a supply of blood to the tumor as other cancers, novel treatments like IPI-926 may be critical in helping fight this type of cancer, researchers said.

"If these results hold in future studies, we hope that scientists will be able to make better use of current treatments and develop a range of new options which will help people with pancreatic cancer live longer," Dr. Lesley Walker of Cancer Research UK, which helped fund the study, said.

(Reporting by Michael Kahn; editing by Maggie Fox and Farah Master)

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