Doctors concerned about side effects of Crohn's disease drug

Doctors are learning more about the dangerous side effects of a so-called miracle drug used to treat Crohn's disease.

Remicade went on the market a few months ago in Canada after heavy lobbying by patients.

• DISCLOSURE: The Remicade Letters

Crohn's is a chronic, painful condition that affects the bowel and intestines. Remicade is the first new class of drug to treat the disease in over 30 years. It was approved in the U.S. in July 2000 after two clinical trials.

Remicade blocks a chemical that causes inflammation, making the pain of Crohn's disease disappear in some patients.

"For me it was unbelievable, like day and night," says Heather Ayre, a Crohn's sufferer.

Ayre has tried other medications and also had her colon removed, but nothing helped until Remicade came along.

"You can't really put a price on it. Every day that you're healthy and you're active, you're busy, you're out there enjoying (life)," says Ayre.

But there are risks. The drug suppresses the immune system, leaving patients open to serious infections.

Patients in clinical trial die

Because it's such a new drug, adverse reactions are only just being reported. In the U.S., some patients have contracted tuberculosis while on Remicade.

"We are advocating that patients receive a TB skin test and personally I also do a chest X-ray," says Dr. Remo Panaccione who helped write the practice guidelines for Crohn's patients in Canada.

The drug has other worrying consequences. Some patients in the first clinical trial developed lymphoma, cancer of the lymph system.

Doctors worry the drug may be causing heart damage

Another trial, looking at Remicade for treatment of congestive heart failure, was halted because some of the participants died, others got worse.

Doctors worry the drug may be causing heart damage in Crohn's patients.

"I think this is a something we need to be careful of especially in the elderly patients who may have concurrent heart disease," says Panaccione.

Health Canada is watching the drug closely.

"What we don't know is how many people will develop a serious infection," says Dr. Ken Bassett who works with Therapeutics Initiatives, the group that evaluates new drugs.

"We don't how many people will develop new malignancies."

Doctors warn Remicade was never intended to work for every Crohn's patient. The latest clinical trial data by the manufacturer indicates the drug may only be working in half of the cases.