Patient case (clinical description): A 39-year-old man comes to the emergency department with an acute onset of severe left toe pain.  The toe is red and exhibits swelling. The patient is not febrile, and does not remember any recent trauma. Medical history is not significant except for the similar attacks and the diagnosis of gouty arthritis. His medication history includes Allopurinol to prevent gouty attacks. His father has the same medical condition. However, his older brother who is 41 years old is healthy with no history of gouty arthritis. Physical examination shows a swollen, tender first metatarsophalangeal joint.  Aspiration of the joint showed high leukocyte count, negative Gram stain, and numerous needle-shaped crystals, which is compatible with gouty arthritis.

Patient's own account: I'm a 39-year-old man and got admitted to the ER after an unbearable pain in my left toe. My toe was red and terribly swollen. I was still standing on my feet, not febrile and I don't remember hitting my head or anything. I don't have any special medical history, but I had been diagnosed with gout before. I take Lopurin to prevent my gouty attacks. My dad had the same problem, but my 41-year-old brother is healthy and does not have gouty attacks. The doctor did a physical exam and found that the joints between my toes and the rest of my foot were swollen and tender. The doctor renewed his diagnosis of gouty arthritis.

Clinical trial: Gout Dose Response Study

Eligibility criteria:
Inclusion Criteria:

          -  Male or post-menopausal or surgically sterile female.

          -  18 - 75 years of age.

          -  Hyperuricemic (i.e., screening sUA ≥8 mg/dL).

          -  Meets criteria for the diagnosis of gout as per the American Rheumatism Association
             (ARA) Criteria for the Classification of Acute Arthritis of Primary Gout.

          -  Willing and able to give informed consent and adhere to visit/protocol schedules
             (informed consent must be given before the first study procedure is performed).

          -  Subjects entering the optional Extension Period must have successfully completed the
             Double-Blind Treatment Period and Follow-up Period within approximately 4 months and
             must not have experienced any serious adverse events considered possibly related to
             study drug.

        Exclusion Criteria:

          -  Classified as an overproducer of urine urate (Cur > 6.0 ml/min/1.73 m2 24- hour
             urine).

          -  Consumes more than 14 drinks of alcohol per week (e.g., 1 drink = 5 oz [150 ml] of
             wine, 12 oz [360 ml] of beer, or 1.5 oz [45 ml] of hard liquor).

          -  History or suspicion of drug abuse.

          -  Documented history of or suspicion of kidney stones.

          -  History of rheumatoid arthritis or other autoimmune disease.

          -  Confirmed (positive serology to HIV1 and HIV 2) or suspected HIV infection.

          -  Positive serology to HCV antibodies (Abs), and/or hepatitis B surface antigen (HBsAg).

          -  History of malignancy, except treated non-melanomatous skin cancer or cervical
             dysplasia.

          -  History of cardiac abnormalities, including abnormal and clinically relevant ECG
             changes such as bradycardia (sinus rate <45 bpm), complete left bundle branch block
             (LBBB), second or third degree heart block, intraventricular conduction delay with QRS
             duration >120 msec, symptomatic or asymptomatic arrhythmias with the exception of
             sinus arrhythmia, evidence of ventricular pre-excitation, frequent palpitations or
             syncopal episodes, heart failure, hypokalemia, family history of Long QT Syndrome,
             and/or family history of sudden death in an otherwise healthy individual between the
             ages of 1 and 30 years.

          -  Any condition predisposing them to QT prolongation including pathological Q-wave
             (defined as Q-wave >40 msec or depth > 0.4-0.5 mV).

          -  Any use of a concomitant medication that prolong the QT/QTc interval within the 14
             days prior to Baseline (Day 0)

          -  QT interval corrected for heart rate according to Fridericia (QTcF) > 450 msec at
             Screening or pre-dose at Baseline (Day 0)

          -  Uncontrolled hypertension (above 150/95)

          -  Inadequate renal function

          -  Hemoglobin < 10 g/dL (males) or < 9 g/dL (females)

          -  Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > 2.5 x upper limit
             of normal (ULN)

          -  Gamma glutamyl transferase (GGT) > 3 x ULN

          -  Active peptic ulcer disease requiring treatment

          -  History of xanthinuria, active liver disease, or hepatic dysfunction.

          -  Requires therapy with any other urate-lowering medication, other than the study
             medication.

          -  Requires long-term use of salicylates; diuretics; azathioprine; mercaptopurine;
             theophylline; intravenous colchicine; cyclosporine; cyclophosphamide; pyrazinamide;
             sulfamethoxazole; or trimethoprim

          -  Taking medications known as enzyme inducers

          -  Receiving a strong or moderate inhibitor of CYP3A4 or a P-gp inhibitor within 1 month
             prior to study drug dosing

          -  Gout flare at screening that is resolved for less than one week prior to the first
             treatment with study medication (exclusive of chronic synovitis/ arthritis)

          -  Female of childbearing potential

          -  Received an investigational medication within 4 weeks prior to study medication
             administration

          -  Previously participated in a clinical study involving RDEA806 or RDEA594.

          -  Known hypersensitivity or allergy to RDEA594 or colchicine or any components in their
             formulations.

          -  Body mass index (BMI) >40 kg/m2.

          -  Taking greater than 1000 mg/day of Vitamin C.

          -  Any other medical or psychological condition, which in the opinion of the Investigator
             and/or Medical Monitor, might create undue risk to the subject or interfere with the
             subject's ability to comply with the protocol requirements, or to complete the study.

          -  Inadequate renal function after completing the Double-Blind Treatment period prior to
             entering Extension Period.

          -  Requiring treatment with prohibited medications noted in exclusion criteria numbers
             20-23 after completing the Double-Blind Treatment Period prior to entering the
             Extension Period.

          -  Clinically relevant medical event as determined by the investigator in consultation
             with medical monitor prior to entering the Extension Period.
No condition on gender to be admitted to the trial.
No healthy subjects accepted to join the trial.
Subject must be at least 18 Years old.
Subject must be at most 75 Years

Eligibility (NLI label): Contradiction