The purpose of this study was to study the effect of different combinations of fenofibrate and metformin on the cluster of metabolic syndrome (MetS) biochemical abnormalities, and to determine the dose combination allowing normalization of MetS patients.

Inclusion Criteria:

• Male or female patients aged from 18 to 75 years old (at inclusion V1).
• With 3 of the following 5 criteria, including at least 2 biochemical abnormalities (glucose and one lipid abnormality)
• And having signed a written informed consent (at inclusion V1).

Exclusion Criteria:

• known Type 1 diabetes, or treated type 2 diabetes [25], [26];

• wth HbA1c > 8 % [27] at the first blood sample;

• body mass index (BMI) > 45 kg/m2;

• females who were not surgically sterilized or not using adequate contraceptive or not using adequate contraceptive precautions or not postmenopausal

• pregnant or lactating women;

• known hypersensitivity to fibrates;

• known hypersensitivity to metformin chlorhydrate; known abnormal thyroid hormone levels, or high thyroid stimulating hormone (TSH) level;

• having received an investigational drug in the last 30 days before the date of randomization;

• unable or unwilling to comply with the protocol;

• likely to withdraw from the study before its completion;

• treated with some concomitant medications:

• reporting a change within the last 6 weeks before randomization and during the study in the medications that could interfere with the lipid profile (i.e., anti-hypertensive drugs, oral corticosteroids, thyroid hormones, retinoids, thiazidic derivatives, hormone replacement therapies);

• presenting with the following disease or conditions:

  • chronic respiratory insufficiency, patient with medical device for sleep apnea;
  • current chronic pancreatitis, or identified risk or known history of acute pancreatitis;
  • hepatic insufficiency, acute alcohol intoxication, alcoholism;
  • known cholelithiasis without cholecystectomy;
  • aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) > 2 times the upper limit normal (ULN);
  • musculoskeletal disease or increased creatine phosphokinase (CPK) > 3 times the ULN;
  • renal failure or renal dysfunction defined by serum creatinine levels > 135 μmol/L in males and > 110 μmol/L in females [28];
  • acute conditions with the potential to alter renal function such as dehydration, severe infection, shock or intravascular administration of iodinated contrast agents;
  • acute or chronic disease which may cause tissue hypoxia such as cardiac or respiratory failure, recent myocardial infarction (within 3 months prior to randomization), shock;
  • known gastric or peptic ulcer or intestinal disease within the previous 3 months of randomization capable of modifying the intestinal absorption of the drugs;
  • any other severe pathology such as cancer, mental illness, etc., which in the opinion of the investigator might pose a risk to the patient or confound the results of the study