Kineret – the chemical name is anakinra- is a biologic drug that blocks the effects of interleukin 1. Interleukin 1 is a protein that is produced in excess in people with rheumatoid arthritis (RA). It, along with tumor necrosis factor (TNF), seem to be the most important proteins involved in rheumatoid arthritis inflammation.
Interleukin 1 is a major contributor to the pain, inflammation, and joint damage seen with RA. Kineret needs to be injected subcutaneously (under the skin) daily. The dose is 100 mgs per day. It is recommended for patients not experiencing effective relief from other rheumatoid arthritis therapies such as methotrexate or anti-TNF drugs like Enbrel, Humira, and Remicade.
The clinical trials that studied Kineret showed that the drug led to 20 per cent improvement in 34 to 43 per cent of those taking the drug versus 22 to 27 per cent of those patients taking placebo. These statistics are not that impressive.
Side effects of anakinra include bruising and pain at the injection sites as well as an increased risk of infection. Kineret should not be used together with anti-TNF drugs since this combination markedly increased the rate of infection in the one major clinical trial that evaluated the combination.
Anakinra should not be started in patients who have an active infection. It should be held in those who develop a significant infection (one requiring antibiotic therapy). It can be restarted once the infection is controlled and the antibiotic course is completed..
Another side effect is a drop in white blood cell count. Routine laboratory testing including a complete blood count and chemistry panel should be performed on monthly basis.
Our experience with Kineret has not been a positive one. It seems to work for a minority of patients. There may be a niche somewhere for this drug. Nonetheless, it is a worth a try in patients who have failed other biologic therapies.