Rasburicase is a genetically engineered enzyme. It causes uric acid to break down to allantoin which is more soluble, and easily excreted by the kidneys.
Though rasburicase is very effective at reducing uric acid levels, it is not approved for long term use. FDA approval is limited to counteracting the effects of chemotherapy in children over a maximum of 5 days.
There have been a small number of European studies of rasburicase and gout, but I am not aware of any proper clinical trials.
Tausche and Schroder comment in Annals of the Rheumatic Diseases that the main dilemma…
… is not the high cost but the missing approval by the FDA in severe tophaceous gout.
Of course, mass production might bring the cost down, but rasburicase has another drawback. It is administered intravenously, over a 30 minute period.
A similar drug, Puricase, is currently undergoing trials. FDA submission is expected late this year, or early next year.
The intention for both these drugs is that they will only be considered when other treatments, usually allopurinol, have failed or are inappropriate.
What are your views on rasburicase and gout?
As of October 16th this year, rasburicase approval is extended in the US to include adult chemotherapy patients. It remains as a daily intravenous infusion limited to a five day course.
The brand name is Elitek, manufactured by Sanofi Synthelabo.
It is unlikely that rasburicase will be adopted as a mainstream gout treatment. It often produces an immune reaction, and only extreme medical cases warrant the risks of treatment. The other form of uricase that I mention in the article is pegloticase, now approved as a gout treatment, and marketed as Ktystexxa in the United States.
I have included rasburicase in the list of potential new gout medicines. I will continue to monitor rasburicase and gout, and post updates if the situation changes.