Efficacy and Tolerability of Exenatide Once Weekly Over 6 Years in Patients with Type 2 Diabetes: An Uncontrolled Open-Label Extension of the DURATION-1 Study

Background: Long-term treatment is necessary to slow the progression of type 2 diabetes (T2D). Here, we examined the safety and efficacy of 6 years of treatment with exenatide once weekly (QW) among patients with T2D in the DURATION-1 trial. Methods: The study enrolled patients aged ≥16 years with T2D treated primarily with metformin and sulfonylureas. Following 30 weeks of randomized treatment with exenatide QW 2 mg or exenatide twice daily 10 μg, patients entered an uncontrolled, open-label, open-ended study phase in which all patients received exenatide QW 2 mg. Restrictions on concomitant medication use were eased over time. Results: Of the original 295 patients in the intent-to-treat population, 136 (46%) completed 6 years of treatment. Six-year completers had sustained significant improvements from baseline in glycated hemoglobin (HbA1c; least-squares mean [LSM] change, −1.6%), with 46.3% achieving HbA1c <7.0%, 33.1% achieving HbA1c ≤6.5%, and significant improvements from baseline in fasting plasma glucose (−28 mg/dL) and body weight (−4.2 kg) at 6 years. The 78 completers who added no glucose-lowering medications had numerically greater body weight reductions than the overall cohort (6-year LSM change, −6.1 kg) with more stability over time. No unexpected adverse events were observed during 1202.4 patient-years of exposure. Most minor hypoglycemia events occurred with concomitant sulfonylurea use. Conclusions: Exenatide QW was associated with clinically significant, sustained improvements in glycemic control and weight in patients who continued therapy for up to 6 years, without unexpected safety findings. ClinicalTrials.gov registration: NCT00308139.