PARIS — The overwhelming majority of osteoarthritis patients who will respond favorably to a given cyclooxygenase-2 selective NSAID will do so within the first 2 weeks, a pooled analysis of two placebo-controlled clinical trials has shown.
Thus, the 2-week mark is a reasonable time in which to consider whether to switch a patient to a different NSAID, Dr. Steven S. Smugar said at the annual European Congress of Rheumatology.
However, a case also can be made for using a more conservative decision point at 4 weeks. That's because 28% of nonresponders after 2 weeks became responders by week 4 in this post hoc pooled analysis. But the absolute number of patients who fell into this delayed-responder subgroup was small, added Dr. Smugar of Merck & Co., West Point, Pa.
He reported on 1,207 patients with knee or hip osteoarthritis who were randomized to 12 weeks of once-daily etoricoxib (Arcoxia, not available in United States) at 30 mg, celecoxib (Celebrex) at 200 mg, or placebo in two identical double-blind clinical trials sponsored by Merck.
After 12 weeks, 66% of patients in the etoricoxib group, 64% in the celecoxib group, and 43% on placebo had a favorable response as defined primarily by at least a 50% improvement in pain or function and an absolute change of 20 mm or more on a 100-mm visual analog scale.
Eighty-four percent of responders at week 2 remained responders at week 12. The durability of response was good, demonstrated by the fact that, among responders, 74% were consistent responders at all four of the study assessment points at 2, 4, 8, and 12 weeks, according to Dr. Smugar.
Of 360 nonresponders at week 2, 60% remained nonresponders at week 12.
