By Justin Gillis
Washington Post Staff Writer
Wednesday, March 1, 2006
The world's best-selling cancer drug won federal approval yesterday to treat an entirely different disease, rheumatoid arthritis, in a development that doctors called a symbol of their rapidly advancing knowledge of disease biology.
The drug, Rituxan, is among a new group of cancer treatments that are more precise and less toxic than older chemotherapy compounds. The success of the biotechnology industry in developing such treatments has been a major factor in the stock market recently, propelling the shares of some companies to new highs.
One of the bellwether stocks is Genentech Inc., the first biotech company and, lately, one of the most successful at bringing new treatments to market. Genentech, of South San Francisco, Calif., sells Rituxan in collaboration with Biogen Idec Inc. of Cambridge, Mass.
The action yesterday by the Food and Drug Administration, which came after the stock market closed, shows that at least some of these drugs are likely to find broad markets well beyond cancer treatment, a prospect that could propel a handful of them into the stratosphere of drugs with multibillion-dollar sales. Rituxan, which sells for about $18,000 per patient per year wholesale, had already achieved $1.8 billion in annual sales labeled as only a cancer treatment.
Sales for rheumatoid arthritis are likely to be relatively modest, at least in the short run, with some analysts projecting $100 million a year or so. That number could rise over time as doctors broaden their use of the drug, but growth could be limited by cost and other factors. The drug does not work for some people, and doctors are not entirely sure yet how to use it.
Rituxan is by no means the first drug invented for one disease to be found useful in treating another, nor is it even the first cancer drug to follow that course. But historically, such discoveries tended to be made by accident. Viagra, for instance, was invented as a heart treatment; in the course of learning it was a failure for that purpose, doctors noticed it was ameliorating impotence in some men.
Rituxan, by contrast, illustrates a dawning era in which doctors know enough biology to predict that a drug might be useful in treating several ailments. The drug was first approved in 1997 to treat a blood cancer called lymphoma; it was approved late yesterday to treat rheumatoid arthritis, and tests in other immune diseases, including lupus and multiple sclerosis, are underway.
"I think it's extraordinary," said Stephen A. Paget, chief of rheumatology at the Hospital for Special Surgery in New York, a leading center for treatment of rheumatoid arthritis. "It demonstrates what our science is able to do today."
Angie Jenkins of Cooper City, Fla., a supervisor at an Albertson's grocery store, said she had been taking 13 drugs, including shots, to control a case of rheumatoid arthritis that was causing severe, episodic pain in her joints -- "from my jaw to my big toe" -- and sending her to the emergency room. She enrolled in a test a year ago and received two infusions of Rituxan, and her symptoms virtually disappeared. She has stopped all other treatment.
"You don't know how lucky I feel," she said yesterday. "It's like I stepped out of my own body into another one."
The field of rheumatology, once static, has been thrown into happy turmoil in recent years. Other biotech drugs have also been found useful for rheumatoid arthritis, and many studies are underway to figure out how to use these drugs and understand the risks they pose.
Many of the drugs deliberately suppress some part of the immune system, and the biggest risk so far for the average patient seems to be that they can heighten vulnerability to infections. But the infections themselves are usually treatable, and doctors say some autoimmune diseases can be so debilitating that it is often a tradeoff worth making.
Rituxan is an artificial antibody, created through genetic engineering, that tamps down a certain class of immune cells. Those cells grow out of control in some types of cancer, and they are also overactive in other ailments, rheumatoid arthritis being one.
In that form of arthritis, the immune system attacks a person's joints. It's sometimes mild but, in severe forms, it can be far worse than the wear-and-tear type of arthritis older people get. It can show up early in life, it can put people in wheelchairs, and it sometimes leaves their hands and wrists a gnarled mess.
Many people with severe rheumatoid arthritis are forced to stop working, and they sometimes die early of heart disease or other conditions that seem to show up in such patients at high rates. Despite the advent of new treatments in recent years, 30 to 40 percent of patients, for unknown reasons, derive little benefit from them, and it is in this group that doctors are expected to use Rituxan first. It remains to be seen whether the drug will extend life or merely ameliorate symptoms.
The new treatments "really take people from a situation that was very frustrating and disturbing to one that is hopeful," said Paget, the New York rheumatologist. "Where there was an end of the road and you couldn't go any further, there's now much more road ahead."