This multicenter, open-label extension study of Protocol 2993-112 is designed to assess long-term glucose control as measured by HbA1c (glycosylated hemoglobin) and to evaluate long-term safety and tolerability in subjects treated with metformin who receive subcutaneously injected AC2993 (10 mcg) administered twice daily. Subjects completing Protocol 2993-112 are eligible to enroll.

All of the following criteria are to be fulfilled for inclusion of an individual in the study unless the sponsor grants an exception:

• Has completed the 30-week triple-blind treatment initiation/active treatment periods in Protocol 2993-112, including all procedures required at the study termination visit (Week 30).
• Male or female. Female individuals must be either 1) postmenopausal as documented by serum FSH measurement unless using estrogen for hormone replacement therapy; or 2) of childbearing potential and used appropriate contraceptive methods (surgical sterility or oral, injected, barrier, intrauterine, or implanted contraceptives) for the duration of Protocol 2993-112. This individual must have a current, negative pregnancy test (human chorionic gonadotropin [HCG], beta subunit) regardless of birth control method used. The individual agrees to continue using birth control throughout the study to prevent pregnancy.
• Able to understand and sign a Protocol 2993-112E-specific informed consent form, communicate with the investigator, and understand and comply with the protocol requirements.

Individuals meeting any of the following criteria are to be excluded from the study unless the sponsor grants an exception:

• Has not completed Protocol 2993-112.
• Female individuals who are pregnant, lactating, or planning to become pregnant.