New drug attempts to block one gene that causes cancer

WASHINGTON (AP) — Drug companies are studying a possible new way to switch off one of the many genes that spur cancer growth, but scientists warn it’s too soon to know how well the drugs will work in people.
At issue is blocking a gene named ras that is estimated to contribute to 20-30 percent of cancers.
“This approach to blocking ras has been in the works for seven years,” said National Cancer Institute investigator Jeffrey DeClue, who called the work very promising but cautioned that so far the drugs have been shown to work only in rodents. “Things based on animal systems don’t always translate to humans.”
But The Star-Ledger in Newark, N.J., reported Sunday that drug companies are excited enough about the potential of so-called “farnesyl transferase inhibitors,” or FTIs, that they aim to spend some $500 million for the years of study it will take to prove they work.
Phase I studies, where a handful of people take the pills to ensure they’re not too toxic to study further, began several months ago.
Ras is an oncogene. That means if it mutates, it can spur cancer growth. The idea behind FTIs is to block the protein that tells the ras oncogene to cause that cell growth.
But FTIs aren’t the only hope. It takes five to 10 genetic mutations for a tumor to appear, and scientists are working on numerous drugs to attack all the different genes involved. So far, most scientists have focused on tumor suppresser genes that work to block cancer growth naturally.
“By attacking any one of those events in an intelligent way that doesn’t cause undue toxicity, you may have a real beneficial therapeutic agent,” said DeClue, who called FTIs another promising approach.