BOSTON – In a large, long-term study of canagliflozin versus placebo, an excess of discontinuations in the placebo group contributed to a dampening in the magnitude of improvement in hemoglobin A1c.
That’s according to investigators who reported the findings at the annual meeting of the American Association of Clinical Endocrinologists.
A higher rate of starting new antihyperglycemic agents in the placebo arm also likely contributed to the decrease in the difference in HbA1c after 52 weeks in CANVAS (Canagliflozin Cardiovascular Assessment Study), according to investigator Carol Wysham, MD, of the University of Washington, Spokane.
As previously reported, the two randomized trials in the CANVAS program showed that canagliflozin reduced risk of cardiovascular events in patients with type 2 diabetes at elevated risk of cardiovascular disease.
While the CANVAS program was not designed to assess glucose lowering – and, in fact, allowed adjustment of background antihyperglycemic agents at any time – canagliflozin patients were more likely than placebo-treated patients to achieve HbA1c less than 7.0%.
However, the mean placebo-subtracted reduction in HbA1c peaked at –0.64% at week 26 but shrank to –0.24% by week 338, the end of the study.
“In this case, [the analysis] is helping to understand why we might have seen a deterioration in A1c control over a very long period of time,” Dr. Wysham explained.