ΔACR50 at six months was strongly correlated with results obtained at three months
WEDNESDAY, Nov. 18, 2015 (HealthDay News) — For patients with rheumatoid arthritis (RA), the American College of Rheumatology (ACR) 50 responses measured at three months can predict six-month treatment efficacy, according to research published online Oct. 30 in the Journal of Clinical Pharmacology.
Yehong Wang, Ph.D., from Genentech Inc. in San Francisco, and colleagues examined the correlation between short-term and long-term treatment effect measured by the ACR50 using data from a RA database, constructed from 68 reported trials. The authors quantified the relationship between three- and six-month ACR50 treatment effects.
The researchers found that the ΔACR50 at six months correlated strongly with that seen at three months, moderately with that seen at two months, and weakly with that seen at less than two months. A scaling factor based on the ratio of six- to three-month treatment effects was estimated at 0.997, indicating that the treatment effects were approaching a plateau at three months. The scaling factor was not significantly affected by drug classes, baseline 28-joint Disease Activity Score, or the magnitude of control-arm response.
“This work quantitatively supports the empirical clinical development paradigm of using three-month efficacy data to predict long-term efficacy and to inform the probability of clinical success based on early efficacy readout,” the authors write.
Several authors disclosed financial ties to Genentech and F. Hoffmann-La Roche; one author is employed by Quantitative Solutions, a pharmacometrics consulting company.
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