Conditions: Type 2 Diabetes Mellitus
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 402
Healthy volunteers: no

Brief summary:
The purpose of this study is to assess the safety and efficacy of omarigliptin compared to placebo in participants with inadequate glycemic control on metformin monotherapy. The primary hypothesis is that after 24 weeks, the addition of treatment with omarigliptin provides greater reduction in hemoglobin A1c (A1C) than placebo.

Detailed description:
Participants received blinded omarigliptin or matching placebo to omarigliptin for 104 weeks. During the first 24 weeks (Phase A) they did not receive any other blinded study medication. In Phase B (subsequent 80 weeks), participants who did not initiate glycemic rescue in Phase A received additional blinded study medication: participants in the omarigliptin group received placebo to glimepiride and participants in the placebo group received glimepiride.

Arms:
arm 1: Phase A: Omarigliptin 25 mg capsule administered orally once weekly for 24 weeks. Phase B: Omarigliptin 25 mg capsule administered orally once weekly and matching placebo to glimepiride tablet/capsule administered orally once daily for 80 weeks. Participants will continue pre-study metformin throughout the duration of the study. If necessary, rescue therapy may be initiated (open-label glimepiride during Phase A and insulin glargine during Phase B). arm 2: Phase A: matching placebo to omarigliptin orally once a week for 24 weeks. Phase B: Matching placebo to omarigliptin capsule administered orally once weekly and glimepiride 1 or 2 mg tablet/capsule administered orally once daily (titrated up to 6 mg daily) for 80 weeks. Participants will continue pre-study metformin throughout the duration of the study. If necessary, rescue therapy may be initiated (open-label glimepiride during Phase A and insulin glargine during Phase B).

Interventions: intervention 1: Omarigliptin intervention 2: Matching placebo to omarigliptin intervention 3: Glimepiride intervention 4: Matching placebo to glimepiride intervention 5: Insulin glargine intervention 6: Metformin
Intervention descriptions: intervention 1: Omarigliptin 25 mg capsule administered orally once weekly (preferably on the same day of each week) intervention 2: Matching placebo to omarigliptin capsule administered orally once weekly (preferably on the same day of each week) intervention 3: Glimepiride 1 or 2 mg tablet/capsule administered orally once daily and up-titrated to a maximum dose of 6 mg daily. Participants rescued with open-label glimepiride during Phase A will not receive glimepiride or matching placebo to glimepiride during Phase B. intervention 4: Matching placebo to glimepiride tablet/capsule administered orally once daily and up-titrated to a mock maximum dose of 6 mg daily. Participants rescued with open-label glimepiride during Phase A will not receive glimepiride or matching placebo to glimepiride during Phase B. intervention 5: During Phase B of the study, participants who received a maximum up-titration of open-label glimepiride or blinded glimepiride/matching placebo to glimepiride, may be rescued with open-label insulin glargine. intervention 6: Participants continue stable pre-study dose of metformin tablet(s) administered orally (\>= 1500 mg daily) throughout the study.

Protocol document: