medwireNews: Real-world findings suggest that nonresponse to certolizumab pegol based on CDAI scores at 3 months is a good indicator that patients with rheumatoid arthritis (RA) are unlikely to achieve the therapeutic target of low disease activity at 1 year.
Alain Saraux (CHU de la Cavale-Blanche, Brest, France) and colleagues therefore suggest using the CDAI – “a simple tool for physicians to use in daily practice” – to measure response at 3 months in order to "predict treatment failure as early as possible, so that therapy can be adjusted to optimise the long-term clinical outcome.”
Within this study, individuals were classified as nonresponders if their CDAI score was greater than 22 points after 3 months of treatment, or if their DAS28-ESR or HAQ-DI decreased by at least 1.2 or 0.22 points, respectively, during the first 3 months of receiving certolizumab.
Based on CDAI scores alone, 16.7% of the 532 patients from the ECLAIR cohort were classified as nonresponders to certolizumab pegol after 3 months of treatment. In total, 89% of these CDAI-classified nonresponders failed to achieve low disease activity at 12 months, regardless of disease severity at baseline or treatment history.
Saraux and study co-authors emphasize the “very high” 96% specificity of CDAI’s predictability, with less than 5% of patients who responded to treatment at 12 months having had an early nonresponse.
DAS28-ESR and HAQ-DI nonresponse also predicted low disease activity after a year of treatment but to a lesser degree, with only a respective 69.0% and 74.5% of patients classified as such at 3 months failing to achieve low disease activity at 12 months.
Indeed, the investigators deemed the predictability of DAS28-ESR and HAQ-DI to be “good” only in patients with high disease activity at baseline or in those who had previously taken biologic DMARDs.
The researchers acknowledge a drawback of the study in that the CDAI criteria for early nonresponse fails to capture certain patients who remained above the 22 threshold but experienced large drops in CDAI scores.
Additionally, they say that “the evolution of treatment response over time (beyond [12 months]) and long-term safety outcomes are clinically important considerations in longstanding diseases such as RA,” but these were not captured within this study.
Reporting in RMD Open, the authors conclude: “CDAI and DAS28(ESR) could be used to ensure that patients are not unnecessarily exposed to ineffective therapy, by identifying likely failure at 3 months.”
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