[Islam-Online- Science, Ideas & Technology]

PARIS (AFP) - A new gene therapy acts like a sniper's rifle to target cancer of the neck and head, causing many malignant tumors to shrink or disappear, scientists reported in the monthly journal Nature Medicine.

The treatment, clearing the second of three trials in the long process to gaining approval from health authorities, marks an important success for gene therapy, the new frontier in medical research.

Thirty British and American patients with neck and head cancer, a condition that afflicts about half a million people a year and is fatal in a third of cases, were treated with ONYX-015.

A cell-targeting drug delivered via a disabled cold virus, ONYX-015 was injected directly into the tumor and was combined with standard chemotherapy. In 25 of the 30 cases, tumors shrank. In 19 cases, the tumor shrank by at least 50%; in eight of these cases, the tumor completely regressed. Growths as large as 10 centimeters (four inches) disappeared.

The results are especially remarkable given that the patients' cancer had advanced so far that they could not be cured by surgery, radiotherapy or just chemotherapy alone. In addition, in the 19 most successful cases, the tumor had not regrown or reappeared after six months, the researchers said. Previous trials using gene therapy have caused tumors to disappear, only to see them return shortly after the treatment is ended.

Flawed, or mutated, genes are a leading cause of cancer. As many as 70% of the cells in head and neck tumors have mutations in the p53 genes, whose job is to fix the damage that can cause cancer.

ONYX-015 is different from other therapies in that it does not replace a mutated gene with a flawless copy. Instead, it targets cells that are deficient in p53 genes and destroys them, leaving normal cells untouched. Side effects from the treatment were mostly flu-like symptoms, but were within acceptable limits.

In previous tests, ONYX-015 used without chemotherapy had only limited effect, benefiting less than 15% of patients.

The 16-member team included researchers from the University of Texas M.D. Anderson Cancer Center, U.S. Oncology, the Royal Marsden Hospital in London and Britain's Imperial Cancer Research Fund.

In a commentary, Californian cancer expert French Anderson said the success of ONYX-15 indicated, "cancer gene therapy may finally be on the road to success."

There have been several setbacks in gene therapy, including the death in September last year of an 18-year-old U.S. patient who was being treated for a rare liver disease among males.

On the other hand, French doctors earlier this year announced a stunning success in replacing a gene that caused chronic immune deficiency among so-called "bubble babies" who have to spend their lives in sterile plastic tents to avoid infection