Durability and Safety of Imeglimin as an Add-On to DPP-4 Inhibitors in Japanese Type 2 Diabetes: The 104-Week FAMILIAR Trial.
AIMS: To evaluate the long-term efficacy and safety of imeglimin added to dipeptidyl peptidase-4 (DPP-4) inhibitors in Japanese patients with type 2 diabetes, focusing on glycemic durability and safety in elderly patients over 104 weeks. MATERIALS AND METHODS: This multicenter, randomized, placebo-controlled trial comprised a 24-week double-blind phase (imeglimin 1000 mg or placebo twice daily) followed by an 80-week open-label extension in which all patients received imeglimin. Eligible patients had inadequate glycemic control despite DPP-4 inhibitor monotherapy. The main assessment measured HbA1c changes from baseline to week 104. Secondary assessments included meal tolerance tests (MTT) for evaluating physiological changes in β-cell function and insulin resistance and safety monitoring. RESULTS: Of 117 randomized patients, 81 completed 104 weeks. In the early-start group that received imeglimin from week 0, the significant HbA1c reduction observed at week 24 (-0.65%) was maintained through week 104 (-0.55%; p < 0.001 vs. baseline). The delayed-start group that switched to imeglimin at week 24 achieved similar glycemic control thereafter. Elderly patients (≥ 65 years) in the early-start group maintained stable HbA1c reduction (-0.58%) without hypoglycemic events over 2 years. MTT analysis in the early-start group showed sustained improvements in glucose AUC and insulin sensitivity without unnecessary insulin secretion over time. CONCLUSIONS: Imeglimin added to DPP-4 inhibitors appeared to improve glycemic control for 104 weeks, without clear attenuation. The combination was well-tolerated with a low risk of hypoglycemia even in elderly patients. The long-term effect may be associated with improvements in insulin sensitivity. TRIAL REGISTRATION: jRCTs061210082.