A Remicade, or infliximab, is a drug made by US drug giant Johnson & Johnson, the baby-powder people. But this is no benign baby drug; this is a powerful medication for people with moderate-to-severe Crohn’s disease who have had an 'inadequate response' to conventional therapy - as J&J’s literature benignly puts it.

Crohn’s disease is a chronic inflammation of any part of the gastrointestinal tract, but it usually occurs where the small intestine joins the large intestine, and causes pain, fever and chronic diarrhoea. The most serious complication is when the inflammation causes the intestines to become swollen to the point where they become blocked.

The first-line conventional treatment is an anti-inflammatory drug such as mesalazine (Asacol, Pentasa, Salofalk), but many people can’t tolerate the side-effects (one of which is, ironically, diarrhoea). More powerful still are the corticosteroid drugs which, although they may give short-term relief of symptoms, aren’t curative and can have severe side-effects such as osteoporosis. Immunosuppressive drugs are also often used in combination with steroids, but they can lay the patient open to infection.

Infliximab is a new drug targeted at tumour necrosis factor (TNF), a natural substance produced by the body’s immune system, and believed to cause the inflammation in Crohn’s. Infliximab is claimed to remove TNF from the bloodstream before it reaches the intestines, thereby preventing the inflammation.

The question is: does it work and what are the side-effects?

As the drug is delivered by infusion directly into the bloodstream, the most immediate side-effect is a local adverse reaction to the injection itself. In addition to this ‘hypersensitivity’, there may be what are described as 'serious infections' of the skin and surrounding tissues. For this reason, only one infusion is allowed every three months.

However, a wide range of other side-effects has been discovered, affecting a staggering 85 per cent of patients. This includes the usual reactions to powerful drugs such as headache, nausea and vomiting, but also adverse effects on the immune system as a whole, leading to upper respiratory tract infections, bronchitis and fever - to name just a few of the 70 side-effects reported by the manufacturer during early clinical trials.

However, as the drug has begun to be marketed more widely, even more serious problems are showing up.

Top of the list is what’s described as 'an unusually large number of cases of tuberculosis, often with widespread dissemination' (Ann Med Interne [Paris], 2002; 153: 429-31). In addition to TB, other mycobacterial and fungal infections have been seen. Even the manufacturer admits that such infections have caused death in some patients taking the drug.

Also reported are 'serious adverse events' such as congestive heart failure, drug-induced lupus (an autoimmune, inflammatory disorder of the skin, joints and kidneys) and, most worrying of all, loss of the protective myelin sheath (demyelination) of the nerves - the core problem in multiple sclerosis (Drug Saf, 2003; 26: 23-32).

More recently, doctors have also found 'life-threatening' bone-marrow toxicity and severe Parkinson’s disease (Rheumatology [Oxford] 2003; 42: 193-4, 702-3).

So, to compensate for that frightening litany of toxic side-effects, you’d expect infliximab to deliver some major benefits. But does it?