Recruitment Details

Key information relevant to the recruitment process for the overall study, such as dates of the recruitment period and locations
Subjects were enrolled at 167 investigative sites in the United States from 21 February 2003 to 07 April 2004.

Pre-Assignment Details

Significant events and approaches for the overall study following participant enrollment, but prior to group assignment
Subjects currently receiving urate-lowering therapy discontinued those urate-lowering therapies and initiated prophylactic medications before enrollment in once daily (QD) treatment groups.

Reporting Groups

	Description
Febuxostat 80 mg QD	Febuxostat 80 mg, orally, once daily for up to 28 weeks.
Febuxostat 120 mg QD	Febuxostat 120 mg, orally, once daily for up to 28 weeks.
Febuxostat 240 mg QD	Febuxostat 240 mg, orally, once daily for up to 28 weeks.
Allopurinol QD	Allopurinol, orally, once daily for up to 28 weeks. Dose of allopurinol received was based on renal status. Subjects with serum creatinine ≤1.5 mg/dL received 300 mg once daily; subjects with serum creatinine >1.5 mg/dL and ≤2.0 mg/dL received 100 mg once daily.
Placebo QD	Placebo, orally, once daily for up to 28 weeks.

Participant Flow:   Overall Study

	Febuxostat 80 mg QD	Febuxostat 120 mg QD	Febuxostat 240 mg QD	Allopurinol QD	Placebo QD
STARTED	267	269	134	268	134
COMPLETED	174	200	86	211	101
NOT COMPLETED	93	69	48	57	33
Lost to Follow-up	19	17	9	17	10
Adverse Event	18	16	11	18	5
Personal Reason(s)	16	16	9	9	9
Other	15	8	6	5	3
Gout Flare	13	6	8	1	0
Protocol Violation	6	3	3	6	3
Therapeutic Failure	6	3	2	1	3

Reporting Groups

	Description
Febuxostat 80 mg QD	Febuxostat 80 mg, orally, once daily for up to 28 weeks.
Febuxostat 120 mg QD	Febuxostat 120 mg, orally, once daily for up to 28 weeks.
Febuxostat 240 mg QD	Febuxostat 240 mg, orally, once daily for up to 28 weeks.
Allopurinol QD	Allopurinol, orally, once daily for up to 28 weeks. Dose of allopurinol received was based on renal status. Subjects with serum creatinine ≤1.5 mg/dL received 300 mg once daily; subjects with serum creatinine >1.5 mg/dL and ≤2.0 mg/dL received 100 mg once daily.
Placebo QD	Placebo, orally, once daily for up to 28 weeks.

Baseline Measures

	Febuxostat 80 mg QD	Febuxostat 120 mg QD	Febuxostat 240 mg QD	Allopurinol QD	Placebo QD	Total
Number of Participants   [units: participants]	267	269	134	268	134	1072
Age, Customized   [units: subjects]
<45 years	82	79	33	82	36	312
45 years to <65 years	146	154	71	147	79	597
≥65 years	39	36	30	39	19	163
Age   [units: years] Mean ± Standard Deviation	50.6 ± 12.24	51.2 ± 11.57	54.3 ± 12.83	51.8 ± 12.25	51.5 ± 12.18	51.6 ± 12.17
Gender   [units: subjects]
Female	16	13	8	19	11	67
Male	251	256	126	249	123	1005
Race/Ethnicity, Customized   [units: subjects]
White	200	214	107	206	108	835
Black or African American	38	27	13	33	9	120
Hispanic	13	16	8	17	10	64
Asian	8	8	1	6	3	26
Other	8	4	5	6	4	27
Body Mass Index   [units: subjects]
<18.5 kilogram per meter² (kg/m²)	0	0	0	0	0	0
18.5 kg/m² to <25 kg/m²	10	11	9	15	16	61
25 kg/m² to <30 kg/m²	85	81	42	91	48	347
≥30 kg/m²	172	176	83	161	70	662
missing	0	1	0	1	0	2
Presence of a Primary PalpableTophus   [units: subjects]
Yes	48	53	25	64	29	219
No, but other tophi present	0	3	1	1	1	6
No, and no other tophi present	219	213	108	203	104	847
Serum Creatinine   [units: subjects]
≤1.5 milligram per deciliter (mg/dL)	258	258	129	258	129	1032
>1.5 mg/dL	9	11	5	10	5	40

1.  Primary:

Percentage of Subjects Whose Last Three Serum Urate Levels Are <6.0 Milligram Per Deciliter (mg/dL).   [ Last 3 visits (any last 3 visits up to week 28) ]

2.  Secondary:

Percentage of Subjects Whose Serum Urate Levels Are <6.0 mg/dL at Week 28   [ Week 28 ]

3.  Secondary:

Percentage of Subjects Whose Serum Urate Levels Are <6.0 mg/dL at Final Visit   [ Final Visit (up to 28 weeks). ]

4.  Secondary:

Percent Change From Baseline in Serum Urate Levels at Week 28.   [ Baseline and Week 28 ]

5.  Secondary:

Percent Change From Baseline in Serum Urate Levels at Final Visit   [ Baseline and Final Visit (up to 28 weeks) ]

6.  Secondary:

Percent Change in Primary Tophus Size at Week 28, as Determined by Physical Measurement in the Subset of Subjects With Palpable Tophi at the Screening Visit.   [ Baseline and Week 28 ]

7.  Secondary:

Percent Change in Primary Tophus Size at Final Visit, as Determined by Physical Measurement in the Subset of Subjects With Palpable Tophi at the Screening Visit.   [ Baseline and Final Visit (up to 28 weeks) ]

8.  Secondary:

Change in the Total Number of Tophi at Week 28 in the Subset of Subjects With Palpable Tophi at the Screening Visit.   [ Baseline and Week 28 ]

9.  Secondary:

Change in the Total Number of Tophi at Final Visit in the Subset of Subjects With Palpable Tophi at the Screening Visit   [ Final Visit (up to 28 weeks) ]

10.  Secondary:

Percentage of Subjects Requiring Treatment for a Gout Flare Between Weeks 8 and 28 of the Double-Blind Treatment Period.   [ Weeks 8 through 28 ]