Efficacy and Safety of LixiLan Versus Insulin Glargine Alone Both With Metformin in Japanese With Type 2 Diabetes Mellitus Inadequately Controlled on Basal Insulin and Oral Antidiabetic Drugs

Inclusion criteria : * Patient with type 2 diabetes mellitus (T2DM) diagnosed for at least 1 year before the screening visit (V1). * Patient treated with a stable, once a day basal insulin regimen (ie, type of insulin and time/frequency of the injection), for at least 3 months before the screening visit. * The total daily basal insulin dose should be stable (± 20%) and \<15 U/day for at least 1 month before the screening visit. * Patient receiving 1 or 2 oral anti-diabetic drugs (OADs): the OAD dose(s) must be stable during the 3 months before the screening visit. The OADs can be 1 to 2 out of: * Metformin; * Sulfonylurea (SU); * Glinide; * Dipeptidyl-peptidase-4 (DPP-4) inhibitor; * Sodium glucose co-transporter 2 (SGLT2) inhibitor; * Alpha glucosidase inhibitor (alpha-GI). * Signed written informed consent. Exclusion criteria: * Age \<20 years at screening visit. * HbA1c at screening visit \<7.5% or \>9.5%. * Fasting plasma glucose (FPG) \>180 mg/dL (10.0 mmol/L) at screening visit. * Pregnancy or lactation, women of childbearing potential with no effective contraceptive method. * Use of oral or injectable glucose-lowering agents other than those stated in the inclusion criteria in the 3 months before screening visit. * Previous use of insulin regimen other than basal insulin, eg, prandial or pre-mixed insulin. Note: Short-term treatment (≤10 days) due to intercurrent illness including gestational diabetes is allowed at the discretion of the Investigator. * Use of thiazolidinedione (TZD) within 6 months prior to screening visit. * History of discontinuation of a previous treatment with a glucagon-like peptide-1(GLP-1) receptor agonist due to safety/ tolerability issues or lack of efficacy. * Laboratory findings at the screening visit; including: * Amylase and/or lipase \>3 times the upper limit of the normal (ULN) laboratory range; * Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \>3 ULN; * Calcitonin ≥20 pg/mL (5.9 pmol/L); * Positive serum pregnancy test. * Any contraindication to metformin use according to local labeling. * History of hypersensitivity to any GLP-1 receptor agonist or to metacresol. * Contraindication to use of insulin glargine or lixisenatide according to local labeling. History of hypersensitivity to insulin glargine or to any of the excipients. * Personal or immediate family history of medullary thyroid cancer (MTC) or genetic condition that predisposes to MTC (eg, multiple endocrine neoplasia syndromes). * History of pancreatitis (unless pancreatitis was related to gallstones and cholecystectomy has now been performed), pancreatitis during previous treatment with incretin therapies, chronic pancreatitis, pancreatectomy, stomach/gastric surgery. * Exclusion criteria for randomization at the end of the run-in phase: * HbA1c \<7.5% or \>9.5% at visit 6 (Week -1). * Mean fasting self monitored plasma glucose (SMPG) \>160 mg/dL (8.9 mmol/L), calculated from all available (minimum of 4 self-measurements) values during the 7 days prior to randomization. Note:fasting SMPG on the day of randomization can be included if assessed before randomization. * Average insulin glargine daily dose ≥15 U/day or \<5U/day calculated for the last 3 days before Visit 7. * Metformin total daily dose \<750 mg/day. * Amylase and/or lipase \>3 ULN at Visit 6 (Week -1). The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.