Progress for Crohn's

New medications bring temporary respite from debilitating bowel inflammations

September 13, 2007|By Amber Dance | Amber Dance,Los Angeles Times

Daniel Gray's stomach tells a story.

The gnarled lines across his abdomen are the mementos of three surgeries on his digestive system. The slashes along each side are reminders of the time the stitches broke and the doctors put him into a drug-induced coma for seven weeks, keeping his abdomen open for repeated washes. The doctors made the slits so that they would have enough skin to stretch over the opening when they sewed him together.

Gray, 46, was diagnosed 24 years ago with Crohn's disease, a chronic inflammation of the bowel and intestines that afflicts nearly 1 million people worldwide. Crohn's patients suffer from diarrhea and abdominal pain, and 80 percent eventually will face surgery to remove damaged portions of bowel.

Gray, who lives in Long Beach, Calif., is nearly 6 feet tall but weighs only 125 pounds -- yet his situation is better than it used to be. Lately, scientific research has started catching up with the disease, and modern treatments -- notably, anti-inflammatory medications called TNF blockers -- work for many patients.

Two new drugs are poised to hit the market, and if all goes well, things should soon improve further for Crohn's patients.

On July 31, a Food and Drug Administration advisory committee recommended approval of the drug Tysabri as a medication for Crohn's. Tysabri is already in use for treatment of about 14,000 patients with multiple sclerosis, another autoimmune disease in which the body attacks the sheath surrounding nerve cells. Although the committee's decision is nonbinding, it will allow the FDA to move toward approval of Tysabri for Crohn's.

And in two studies published in the July 19 issue of the New England Journal of Medicine, researchers reported that another drug, Cimzia, was effective at treating about one-third of the studies' 1,330 patients with moderate to severe Crohn's. In addition, 62 percent of patients who responded to Cimzia continued to benefit from the treatment after six months.

UCB, the Belgium-based company that makes Cimzia, has begun filing paperwork with the FDA and plans to seek formal approval soon.

The exact cause of Crohn's disease is unclear, but there appears to be a genetic link. A person is 10 times more likely to have Crohn's if a relative has it.

Symptoms include diarrhea, abdominal pain and bloody stool. Patients with severe Crohn's disease have to do "bathroom mapping," identifying nearby restrooms whenever they plan to go out.

In treating Crohn's, doctors and patients consider a variety of medications. Patients frequently start out with anti-inflammatory drugs such as Azulfidine and Rowasa, then progress to steroids, which are stronger but toxic and can be taken only for a short time. The long-term solution is often to suppress the immune system even further.

Since 1998, many Crohn's patients have been helped by the TNF blockers, which stymie the action of a molecule called TNF (tumor necrosis factor). TNF is produced by immune cells and activates further inflammation.

Two of these drugs, Remicade and Humira, are antibodies that bind to TNF, interfering with its function and helping to prevent symptoms.

Remicade and Humira are the first drugs to make a noticeable dent in the rates of hospitalization and surgery for Crohn's patients, says Dr. Stephen Hanauer, chief of gastroenterology at the University of Chicago.

But they don't work for everyone. Although the antibodies block TNF, they can induce a damaging immune response of their own. Some patients are allergic to them.

For others, the drugs work for a while, and then stop.

Cimzia is also a TNF blocker, but unlike the others it contains only part of the antibody -- the portion that recognizes TNF. The rest of the antibody -- the part that can induce its own immune response -- is replaced with a compound called PEG.

This PEG tail stabilizes the drug, allowing it to stay in the patient's body much longer, explains Hanauer, who was a co-author on one of the recently published Cimzia studies.

That means patients would require treatment only every other month, as opposed to every other week with Humira.

Many of the patients in the two trials had nearly exhausted their treatment options, says Dr. William Sandborn, a gastroenterologist at the Mayo Clinic in Minnesota, who oversaw one of the studies.

"Gains that you see in those patients are particularly important and interesting," he says.

Continuing studies are assessing Cimzia's efficacy over a longer period of time than six months, and preliminary data indicate that it can remain effective for at least 18 months.

Tysabri, another new approach to Crohn's, works by interfering with a different part of the immune response.

During inflammation, infection-fighting white blood cells of the immune system cruise through capillaries, searching for infection. When tissues are infected, they put out signals to slow the blood cells and coax them to enter the tissue. "They're kind of like the exit signs on the expressway," Hanauer says.

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