By Russell W. Read, MD
Counseling patients with HLA-B27/ankylosing spondylitis-associated anterior uveitis regarding when to consider initiating prophylactic therapy to prevent flare-ups is complicated by the difficulties of predicting any patient's disease course and choosing which agent to use. The current study, a large multinational adalimumab trial, supports the drug's use for the prevention of anterior uveitis flares in ankylosing spondylitis patients. Its authors report interesting and important data showing a significant reduction in flare rate during the treatment period compared with the one-year period before using adalimumab.
The results of this 1250-patient study demonstrated differing flare reduction rates by subgroup and a greater reduction in those with recent flares. Flare rates were reduced by more than 50 percent in patients without chronic uveitis, and, even in chronic uveitis patients, by 45 percent. The flares patients did experience were generally mild.
However, the relative efficacy of adalimumab compared with other options, such as sulfasalazine or methotrexate, was not addressed by the study. These latter two agents have been shown to be effective at preventing recurrences of anterior uveitis. Subset analysis of large studies on the use of tumor necrosis factor inhibitors for treating ankylosing spondylitis has largely provided the available data on using these agents in this capacity. These studies have also offered evidence demonstrating that infliximab is useful for treating ankylosing spondylitis but etanercept less so.
Issues to consider in interpreting the current study's results include that while the authors state that prestudy uveitis flares were ophthalmologist-documented, no mention is made of an ophthalmologist diagnosing a flare during the study period. Another potential problem is that of regression to the mean, whereby studies comparing pretherapy flare rates to treatment flare rates may overestimate the treatment's effect, since patients with a higher number of flares during a certain period may reasonably be expected to have fewer flares later as the number of flares evens out over time. The study's subjects were allowed to remain on existing therapy, including low doses of glucocorticoids of less than 10 mg per day, antimetabolites and topical corticosteroids, although the study did allow tapering once adalimumab treatment was initiated. Finally, this was an open-label, uncontrolled study, and all of the caveats that typically accompany the limits of this design should be considered.
Financial Disclosures
Dr. Read is a consultant to Abbott Laboratories. He receives grant support from the EyeSight Foundation of Alabama and Research to Prevent Blindness.