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Monday July 31, 5:01 pm Eastern Time
Cancer gene therapy approach looks good - report
By Maggie Fox, Health and Science Correspondent
WASHINGTON, July 31 (Reuters) - A virus that has been genetically engineered to home in on and destroy cancer cells
has shown strong and lasting effects against tumours in patients when combined with standard chemotherapy, researchers
said on Monday.
They said 25 out of 30 patients with head and neck cancer saw their tumours shrink after they were treated with Onyx
Pharmaceuticals Inc.'s (NasdaqNM:ONXX - news) ONYX-015 along with chemotherapy.
Eight tumours disappeared, Dr. Fadlo Khuri and colleagues at M.D. Anderson Cancer Centre in Houston, working with
teams in Britain, wrote in the journal Nature Medicine.
``ONYX-015 may be able to sensitize infected and uninfected cells to killing by chemotherapy,'' they wrote.
``It is very encouraging because this is the first time there has been a Phase II trial -- a trial with more than just a few
patients in it -- where the tumours have gone away in a significant number and they haven't come back,'' gene therapy
pioneer Dr. William French Anderson of the University of Southern California said in a telephone interview.
``There are lots of Phase I trials where you get tumours to go away but they come back.''
Phase I trials are only to find out if a treatment is safe and involve very few people. Phase II trials involve more people but
volunteers are often critically ill because safety is still being assessed. Phase III trials involve a larger number of people and
are the final phase aimed at determining whether a treatment or drug actually works.
Every year, 500,000 people worldwide are diagnosed with cancer of the head and neck, and about 30 percent of them
die. Such cancers, heavily associated with the use of alcohol and tobacco, are treated at first with surgery, radiation
therapy or both.
But tumours come back in about a third of patients. When this happens, the outlook is grim.
Doctors have tried chemotherapy, but it makes patients ill and does not seem to help them live any longer.
Gene therapy is a possible new approach.
Anywhere between 45 and 70 percent of head and neck tumour cells have mutations in a gene known as p53, which,
when normal, helps repair cancer-causing damage.
ONYX-015 is an adenovirus, a relative of common cold viruses, that has been genetically engineered to attack cells that
lack normal p53.
This makes it technically a gene therapy drug, although unlike other gene therapy approaches ONYX-015 does not repair
or replace a faulty gene, Anderson said.
Last year ONYX-015 showed remarkable effects in head and neck cancer patients, but the effects did not last for long.
Khuri's team combined ONYX-015 with two common cancer chemotherapy drugs -- 5-FU and cisplatin -- to see if it
would help them work better.
``Treatment caused tumours to shrink in 25 of the 30 cases evaluated,'' Khuri's team wrote in their report.
They said only 17 percent of tumours had progressed 6 months after treatment -- which meant the combination of gene
therapy and chemotherapy worked better than any treatment alone. |
