A Study to Evaluate the Lipid Regulating Effects of TRIA-662

Inclusion Criteria: * Patients at least 18 years of age at the time of informed consent (women of childbearing potential must be practicing adequate contraception) * Patients with mean serum TG \> 200 mg/dl (2.26 mmol/l) and \< 700 mg/dl (7.91 mmol/l) as measured at 2 sequential visits during the dietary controlled baseline period (Visits 2 and 3 or Visits 3 and 3a) and having lower level within 25% of upper level (higher value minus lower value)/higher value \< 0.25) * Patients willing and able to sign an informed consent form and follow the protocol Exclusion Criteria: * Patients who are pregnant or nursing * Patients with evidence of hepatic dysfunction \[alanine aminotransferase (ALT) or aspartate aminotransferase (AST) greater than 1.5 times the upper limit of normal (ULN), bilirubin greater than 1.5 times ULN, or cirrhosis\] or renal dysfunction (serum creatinine greater than 140 μmol/l, or nephrotic syndrome) as measured during the baseline phase * Patients with uncontrolled diabetes mellitus (fasting glucose level above 11 mmol/l or HbA1C above 10%) as measured during the baseline phase * Patients with hypothyroidism that is not treated or not stable for at least 6 months prior to study entry * Patients with uncontrolled hypertension (systolic blood pressure above 160 mm Hg and/or diastolic blood pressure above 110 mm Hg) * Patients with systolic blood pressure above 140 mm Hg AND three or more of the following cardiovascular risk factors: * Current cigarette smoker * HDL-C \< 40 mg/dL (1.04 mmol/L) * Coronary heart disease in male first degree relative \< 55 years of age * Coronary heart disease in female first degree relative \< 65 years of age * Male age 45 years or older * Female age 55 years or older * Patients with known hyperuricemia or with a history of gout * Patients with an active peptic ulcer * Patients with known coronary artery disease, cerebrovascular disease or peripheral arterial disease that has previously required percutaneous coronary intervention or surgical intervention * Patients with known intolerance or allergy to niacin * Patients consuming more than 10 alcoholic drinks per week * Patients with a history of drug abuse * Patients receiving any lipid modifying agent within 4 weeks of entry into the baseline period * Patients participating in another clinical trial within 30 days of entry into the baseline period * Patients considered to be non-compliant to study medication (\< 80% study medication) or diet during the placebo-baseline phase * Patients for whom the investigator determines that the study would not be appropriate