Gene therapy shows promise against cancer

Early results promising

August 4, 2000
Web posted at: 12:30 p.m. EDT (1630 GMT)

From staff and wire reports

(CNN) -- Researchers have found evidence that gene therapy may be an effective cancer treatment.

Writing in the journal Nature Medicine, Dr. Fadlo Khuri of the M.D. Anderson Cancer Center at the University of Texas in Houston reported the results of clinical trials using a genetically engineered adenovirus called ONYX-015 in conjunction with standard chemotherapy. The virus, which is related to the common cold virus, had been modified to seek out and destroy cancer cells.

The treatment was completed on 30 patients with head and neck cancers.

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"The results of this study are encouraging in that they represent an incremental improvement in some cases, and in some patients, a dramatic one," said Khuri.

Tumors completely disappeared in eight patients.

"I read everything I could find and I prayed a lot," said Jeanette Brodin, a thyroid cancer patient who now has no sign of the disease. "I decided to go with it (the experimental treatment) and it did work."

After treatment with ONYX-015, another 19 patients experienced a "dramatic reduction" in tumor size. Tumor size in the remaining study subjects decreased by at least half, the report said.

"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 tumors have gone away in a significant number and they haven't come back," said Dr. W. French Anderson, director of gene therapy laboratories at the University of Southern California School of Medicine and editor-in-chief of the Human Gene Therapy Journal.

"There are lots of Phase I trials where you get tumors to go away but they come back."

The next step is a Phase III trial that would involve several hundred participants.

As promising as ONYX-015 is, it has a weakness. The substance must be injected directly into the tumor to work. This makes it ineffective against tumors that are hard to reach or are too small to detect.

And some side effects were reported, including flu-like symptoms such as fever, weakness and chills. But no one stopped treatment because of these effects.

Although gene therapy has been used to treat other conditions, this is the first use of such agents to treat cancers, scientists said. In the past year, there has been evidence the therapy holds promise as a treatment against hemophilia, severe combined immune deficiency, also called "boy-in-the-bubble" disease, and heart disease.

Worldwide, about 500,000 people are diagnosed with head and neck cancers every year. Traditional therapies include surgery, radiation and chemotherapy; some 30 percent of patients die.

CNN Medical Correspondent Rhonda Rowland and Reuters contributed to this report.

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Nature: International Weekly Journal of Science
M.D. Anderson Cancer Center
Human Gene Therapy Journal
American Cancer Society

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