Efficacy and Safety of Simiaowan in Prevention of Acute Flares in Chronic Gout Patients Initiating Febuxostat Therapy

Inclusion Criteria: * Male or female subjects aged 18 to 75 years (time of get informed consent) * Meet the American College of Rheumatology/The European League Against Rheumatism criteria (2015) for the classification of acute arthritis of primary gout * Pain Visual Analogue Scale Score (VAS) ≤ 3 at screening * Serum uric acid ≥7 mg/dL (420μmol/L) at screening * Self-reported history of at least 2 gout flares within 12 months prior to screening * Normal electrocardiogram (ECG), or no clinical significant at screening * Be capable of understanding and complying with protocol requirements Exclusion Criteria: * Occurrence of an acute gout flare ongoing at screening or within 2 weeks prior to screening * Known or suspected of secondary hyperuricemia (e.g. due to renal disorder, hematological disorder, drugs, radiotherapy, chemotherapy or organ transplant) * Use of colchicine, allopurinol, probenecid, benzbromarone, febuxostat or history of intra-articular steroid injection within 4 weeks prior to screening * Use of glucocorticoids, nonsteroidal antiinflammatory drugs (NSAIDs), or cyclooxygenase-2 (COX-2) inhibitors within 1 week prior to screening * History of stroke, transient ischemic attack (TIA), acute myocardial infarction (MI), heart failure (NYHA Class II-IV), coronary intervention procedure (including but not limited to angioplasty, stent placement, coronary revascularization) prior to screening * History of gastrointestinal (GI) bleeding, peptic ulcer disease prior to screening * History of malignancy and/or mental disorder prior to screening * Active infection with hepatitis B, hepatitis C, or has aspartate transaminase (AST), alanine aminotransferase (ALT) or gamma-glutamyl transpeptidase (GGT) values ≥1.2 times the upper limit of normal (×ULN) during the screening period * Presence of severe renal function impairment, or has serum creatinine (sCr) values ≥1.2 (×ULN) during the screening period * History of allergy or intolerance to febuxostat, diclofenac sodium, simiaowan and/or the placebo * History of aspirin-induced asthma, or any other form of allergy to aspirin and other NSAIDs * Other (non-gout) chronic arthritis, acute inflammatory arthritis, autoimmune diseases with arthritis at screening * Being treated with simiaowan at screening * Being treated with azathioprine, mercaptopurine, theophylline, cytotoxic agents at screening * Diagnosis of drug or alcohol dependence or abuse or any condition requiring chronic daily use of pain medication * Pregnant or nursing, or planning to become pregnant or father a child within 3 months after receiving the last dose of study drug * Subjects who participated in another clinical study or clinical trial within 3 months prior to screening * Any other condition(s) that will compromise the safety of the patient, prevent compliance with the study protocol, or compromise the quality of the clinical study, as judged by the investigator