A well-known media doctor once tried to put us straight. “What you (What Doctors Don’t Tell You) don’t realize is that when you (the doctor) use a sharp sword (a powerful drug) sometimes heads get cut off (the patient dies),” he explained.
One very sharp sword indeed is the family of drugs known as monoclonal antibodies, which are designed to fight rheumatoid arthritis.
This is how they work. Doctors have noticed that victims of this crippling disease have excessive amounts of a cytokine called tumour necrosis factor alpha (TNF) in their blood and joints. Cytokines are ‘good guys’ – the body releases them to fight bacteria and viruses – and the resulting battle ends in an inflammation. But this process breaks down in arthritis patients, and cytokines are constantly being released even when there are no bacteria to kill, so causing inflammation around the joints.
Step forward the monoclonal antibodies, which are designed to switch off the cytokine production line. Fine, except that now the patient doesn’t have any natural defence against bacteria and viruses.
As a result, patients on the drugs can die from serious infections, including TB, sepsis and pneumonia, and fatal liver and blood disorders are not uncommon. Patients are also much more prone to develop cancers such as lymphoma – but, until now, doctors have not known to what extent.
A new way of assessing drug safety has been used on two monoclonal antibodies, Remicade (infliximab) and Humira (adalimumab), and with alarming results. Researchers have discovered that patients given either of the two drugs treble their risk of developing cancer. In a group of studies that involved 3,493 rheumatoid arthritis patients taking one of the drugs, 24 developed cancer compared with just three from a group of 1512 sufferers who had been given a placebo.
It’s certainly a sharp sword – but is it worth losing your head over?
(Source: Journal of the American Medical Association, 2006; 295: 2275-85).