Gout attacks.You'll probably end them more quickly if your starting levels uric acid levels are lower. How long is it likely to take?Some results from medication trials.Note The data on this web page about gout attacks, and its conclusions, were based on the large APEX and FACT trials phase three studies comparing febuxostat and allopurinol. It may not apply to you. For just a few examples of a big subject: The positive effect of natural gout treatment, such as high quantity water drinking, special foods and diets, is not included in these studies. Drug companies do not incorporate natural gout remedies into their studies about how a new gout drug performs. The level of uric acid most frequently quoted as the target at which gout crystals dissolve and the process of ending a gout attack begins is 6 mg/dL (357 mmol/L or µmol/L). Not all rheumatologists agree about this level. Some think that 5 mg/dL (297 mmol/L or µmol/L) is a better target. Febuxostat was quite successful in reducing uric acid below the 6 mg/dL For example in the FACT trial after one year: 23% on febuxostat 80 mg daily, 45% on febuxostat 120 mg daily and 2% on allopurinol 300 mg had even reached the less than 4 mg/dL(238 mmol/L or µmol/L) level. Much depends on your starting (baseline) UA levels. Generally, the lower your uric acid levels at the start of treatment, the more likely you are to reach the 6 mg/dL level. This pattern was demonstrated in both the APEX and FACT trials. More patients achieved the target if their starting UA levels were less than 9 mg/dL (536 umol/L or µmol) than if their starting levels were above 10 mg/dL (595 mmol/L or µmol/L). Common sense too tells us that this is true. And the EMEA (European Medicines Agency) report on febuxostat said about the FACT study: "Sub group analysis revealed that the proportion of patients with the last 3 serum urate (uric acid) levels < 6 mg/dL (less than 6 mg/dL) treated with febuxostat or allopurinol was dependent on the baseline sUA (blood uric acid) concentrations." It made a similar point about febuxostat and allopurinol in the APEX study and included these numbers: Allopurinol group patients (300 mg/100 mg daily) reaching less than 6 mg/dL Allopurinol < (less than) 9 mg/dL baseline to (less than) <6 mg/dL 37% Febuxostat group patients, mg daily. Percentage who reached less than 6 mg/dL Baseline < (less than) 9 mg/dL or 9-10 mg/dL. NB. The data on febuxostat is less informative, possibly because some commercially confidential information was excluded from the report. However, you get the point. Using uric acid meters to check your uric acid levels You can monitor your UA levels at home using a uric acid meter, but have the results frequently confirmed by a diagnostic lab and keep your doctor in touch with your scores. The key point is to record and date all results and watch for trend changes over time. Uric acid lowering drugs usually work quite quickly. You should expect some positive results on lowering UA levels within a couple of weeks. Click here to read more about uric acid meters. Getting UA levels down to 6 mg/dL may be the beginning of the end of gout attacks. But the real question is when will gout attacks end, period. How long before gout attacks cease, after UA targets have been reached? From the data published from the APEX and FACT studies this is a harder question to answer with as much precision as readers want. You want to hear that they will end a couple of weeks say, after the target has been reached, but really there are just useful hints. In the FACT trial the EMEA assessors said about reaching the uric acid target: "The proportion of subjects, (ITT population, i.e all treated patients) whose serum uric acid levels were < 6 mg/dL (less than 6 mg/dL) at week 2 and week 52 was similar, demonstrating that a near maximum effect is reached already after 2 weeks of treatment with either febuxostat or allopurinol." However it seems that the effect on ceasing gout attacks, or in the words used by the assessors "no longer required treatment" (for gout flares) takes much longer. Your case may well be different but these are some figures from the FACT trial. After 24 weeks, 64% (both febuxostat groups) and 67% (allopurinol group) no longer required treatment for gout flares, which we shall take to mean that there were no gout attacks causing pain. And after 52 weeks 92% (febuxostat 80 mg daily); 94% (febuxostat 120 mg daily) and 89% (allopurinol 300 mg daily) no longer required treatment for gout flares. So it may take 24 to 52 weeks after the 6 mg/dL target has been reached. MORE SUCCESS IN AN EXTENSION TRIAL After the phase 3 APEX and FACT studies 1,086 patients from both, went on to the Cxx-021 extension trial. Results are in for the first two years. It's still ongoing but patient numbers have fallen. In the 16 - 18 month period (remember they were continuing from either the 28 week APEX or 52 week FACT trials), 3% of patients suffered gout flares. In months 22 – 24, the number was about the same, 2.7%. (Percentages are for combined 80 mg and 120 mg febuxostat daily).That means 97% or 97.3% did not require treatment after the combined APEX or FACT periods plus the extension trial period. For the extension trial the EMEA assessors did not discuss allopurinol and gout flare discontinuation. There is no data on whether gout flares returned, if febuxostat or allopurinol was discontinued by people who had succeeded in not requiring further flare treatment. The severity of the gout attacks was not recorded, or not published.
We have extracted data from the Background Information (aka the CHMP Assessment Report) to prepare this article. If you want to download the whole report, which contains much more data about the trials, click here. This is the EMEA website. After you've arrived, click on the English version of the Public Assessment report. It requires Adobe Reader.
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