Febuxostat More Effective Than Allopurinol at Usual Doses

The 2012 American College of Rheumatology gout treatment guidelines recommend titration of urate-lowering medication doses to achieve target serum uric acid (sUA) levels of less than 6 mg/dL. Analysis of data from a large US managed care cohort showed that at commonly used doses, febuxostat was more effective than allopurinol at reducing sUA to target levels. The researchers suggest this was probably at least partly because the commonly used allopurinol doses were not selected by dose titration, and were almost certainly too low.

Jasvinder A. Singh, MD, professor of medicine, University of Alabama, Birmingham, and colleagues reported the results of their retrospective analysis, which was funded by Takeda, in an article published online May 12 in Arthritis Research & Therapy.

"The key finding is that febuxostat at the doses used commonly was more effective and effective more quickly than allopurinol at the doses used commonly," Dr Singh told Medscape Medical News. "That does not tell us that febuxostat overall is more effective than allopurinol, only that this is what occurs at the commonly used doses. Many people correctly argue that allopurinol as commonly used is not the most effective dose, while febuxostat as commonly used is at the most effective dose."

The researchers conducted a retrospective study of medical and pharmacy claims and laboratory data from a large US commercial and a Medicare Advantage health plan during 2009 to 2011. The study included all patients with at least one medical claim and a diagnosis of gout who had received at least one prescription for febuxostat (n = 2015) or allopurinol (n = 14,025) and who had at least one sUA measurement after that prescription.

More febuxostat users reached sUA target levels, and this happened more quickly than with allopurinol. A sUA level lower than 6.0 mg/dL was achieved by 56.9% of febuxostat users vs 44.8% of allopurinol users (P < .001), and a sUA level lower than 5.0 mg/dL was achieved by 35.5% of febuxostat users vs 19.2% of allopurinol users (P < .001). Febuxostat users reached sUA levels lower than 6.0 mg/dL by a mean of 346 days vs 397 days for allopurinol users (P < .001), and mean time to sUA levels lower than 5.0 mg/dL was 431 days in febuxostat users vs 478 days in allopurinol users (P < .001).

Tuhina Neogi, MD, PhD, associate professor of medicine and epidemiology, Boston University School of Medicine, Massachusetts, told Medscape Medical News, "It's well-known that about half of patients with gout do not achieve adequate control of their gout if their allopurinol dose is at 300 mg or lower. If a low percentage of patients in this study had a dose higher than 300 mg of allopurinol, that would be a legitimate concern." Dr Neogi is involved in other, non-industry-funded gout treatment studies, and was not involved in this study.

The authors report that in the febuxostat group, 83.2% of patients were taking 40 mg/day, and the rest were taking 80 mg/day. In the allopurinol group, only 2.9% of patients were taking more than 300 mg/day. The most commonly used dose was 300 mg/day (42.3% of patients); 14.8% of patients were taking 101 to 299 mg/day, and 40.1% were taking 100 mg/day.