HOUSTON — Colesevelam maintained its glucose-lowering effect up to 78 weeks in an open-label extension study involving 146 patients with type 2 diabetes who were also taking metformin.
Colesevelam (Welchol) is a bile acid sequestrant approved for both glycemic control in adults with type 2 diabetes and lowering low-density-lipoprotein cholesterol levels in adults with primary hypercholesterolemia, Dr. Harold E. Bays and his colleagues said in a poster presentation at the annual meeting of the American Association of Clinical Endocrinologists.
Subjects with type 2 diabetes who completed one of three previous26-week randomized, double-blind, placebo-controlled trials evaluating colesevelam in combination with metformin, insulin, or sulfonylurea were invited to join the 52-week open-label extension study.
All received 3.8 g/day of colesevelam (as six 625-mg tablets), taken either once a day with dinner (six tablets) or twice a day (three tablets with lunch and three with dinner). Patients were given the choice of schedule. All had been previously taking metformin, and continued to take it through the extension study. Doses could be adjusted, however, and other glucose-lowering agents could also be added with the aim of achieving a hemoglobin A1c of less than 7%, said Dr. Bays of the Louisville (Ky.) Metabolic and Atherosclerosis Research Center and his associates.
A total of 222 patients completed the initial randomized, controlled study, and 146 enrolled in the open-label extension. Of those, 81 had received colesevelam in the randomized study and 65 were on placebo (both in combination with metformin). Of those, 56 and 41, respectively, completed the open-label extension.
At the end of the initial 26 weeks, HbA1c levels had dropped from a mean of 8.2% to 7.6% in the colesevelam group, while remaining nearly unchanged in the placebo group (8.1% to 8.2%). These HbA1c levels were maintained over the 52-week extension in the group that had been taking colesevelam the entire 78 weeks, with a final HbA1c of 7.7%.
Those who had been on placebo during the randomized study and were now taking colesevelam achieved a mean HbA1c value of 7.4% by the end of the 52-week extension.
Nine patients discontinued the entire study because of adverse events, including three serious events. Nonserious events deemed possibly or probably related to colesevelam included wheezing, dyspnea, and cough in one patient, abnormal liver function test in one, and dyspepsia in two.
Of 15 serious events reported, 13 were deemed not related to the study drug and two were considered unlikely to be related. Overall compliance in all phases of the study was 88.5%, the investigators reported.
The study was funded by Daiichi Sankyo Inc., which markets colesevelam.