Bristol-Myers Squibb Company (BMY) and Pfizer Inc. (PFE) said Tuesday that results from a prespecified subanalysis of the ARISTOTLE trial showed that the reductions in stroke or systemic embolism, number of major bleeding events and mortality demonstrated with Eliquis compared to warfarin in the ARISTOTLE trial were consistent across subgroups defined based on levels of International Normalized Ratio control in patients with nonvalvular atrial fibrillation.
Variations in time in therapeutic range can affect outcomes for atrial fibrillation patients being treated with Vitamin K antagonists such as warfarin for stroke prevention, leading to an increased risk of stroke when INR levels are below, or bleeding when INR levels are above, the therapeutic range.
The ARISTOTLE study was designed to demonstrate the efficacy and safety of Eliquis versus warfarin for the prevention of stroke or systemic embolism in patients with nonvalvular atrial fibrillation.
The ARISTOTLE trial randomized 18,201 patients from 1,034 clinical centers in 39 countries. In this subanalysis, for each patient, a center average TTR was estimated using a linear mixed model based on the real TTRs in warfarin treated patients with a fixed effect for country and random effect for center. Study centers were placed into one of four similarly sized quartile groups based on cTTR. The rates of stroke or systemic embolism, major bleeding and mortality were consistently lower with Eliquis than warfarin across the cTTR quartiles. Similar results were seen when an individual TTR, predicted using a model including patient characteristics, was examined in a post-hoc analysis.
While demonstrating consistency across a broad range of warfarin control, results of the subanalysis suggest a trend toward reduction of the treatment effects at centers and in patients with predicted excellent INR control. In those centers, interaction tests are less reliable because of low numbers of events, and thereby lack statistical power.
Based on the results of the subanalysis, the benefits of Eliquis compared with warfarin for stroke or systemic embolism, bleeding, and mortality appear similar across the range of centers' and patients' quality of INR control, the two companies said.
For comments and feedback: editorial@rttnews.com