Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

The a priori defined order of the statistical hypotheses was as follows:

1. Superiority of adalimumab 0.8 mg/kg versus MTX for the percentage of participants achieving a ≥ PASI 75 response at Week 16.
2. Superiority of adalimumab 0.8 mg/kg versus MTX, for the percentage of participants achieving a PGA cleared or minimal at Week 16.

This order was adhered to for confirmatory testing, all statistical tests were at a level of significance of 5% and the overall type I error was preserved.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

Statistical comparisons for the ranked secondary endpoints were carried out in hierarchical order. All statistical tests were 2-sided with the significance level of 5%. Statistically significant results (p-value ≤ 0.05) must have been achieved for a comparison in the higher rank in order to initiate the next comparison in the lower rank.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

Statistical comparisons for the ranked secondary endpoints were carried out in hierarchical order. All statistical tests were 2-sided with the significance level of 5%. Statistically significant results (p-value ≤ 0.05) must have been achieved for a comparison in the higher rank in order to initiate the next comparison in the lower rank.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

Statistical comparisons for the ranked secondary endpoints were carried out in hierarchical order. All statistical tests were 2-sided with the significance level of 5%. Statistically significant results (p-value ≤ 0.05) must have been achieved for a comparison in the higher rank in order to initiate the next comparison in the lower rank.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

Statistical comparisons for the ranked secondary endpoints were carried out in hierarchical order. All statistical tests were 2-sided with the significance level of 5%. Statistically significant results (p-value ≤ 0.05) must have been achieved for a comparison in the higher rank in order to initiate the next comparison in the lower rank.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

The difference between the combined adalimumab 0.8 mg/kg + MTX groups versus the adalimumab 0.4 mg/kg group.

Statistical comparisons for the ranked secondary endpoints were carried out in hierarchical order. All statistical tests were to be 2-sided with the significance level of 5%. Statistically significant results (P value ≤ 0.05) must have been achieved for a comparison in the higher rank in order to initiate the next comparison in the lower rank.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

Statistical comparisons for the ranked secondary endpoints were carried out in hierarchical order. All statistical tests were 2-sided with the significance level of 5%. Statistically significant results (P value ≤ 0.05) must have been achieved for a comparison in the higher rank in order to initiate the next comparison in the lower rank.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

Participants received 0.1 mg/kg methotrexate at Baseline (Week 0), and up to 0.4 mg/kg weekly (maximum dose of 25 mg/week) in Period A. Participants also received adalimumab placebo as a single subcutaneous loading dose at Week 0, followed by every other week (eow) dosing from Week 1. Participants who were non-responders in period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.4 mg/kg (up to a maximum of 20 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.4 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.4 mg/kg eow.

In Period A participants received a single subcutaneous loading dose of adalimumab 0.8 mg/kg (up to a maximum of 40 mg) at Week 0 followed by every other week dosing beginning at Week 1. To maintain the blind, participants also received weekly dosing of methotrexate placebo tablets. Participants who were non-responders in Period A entered Period D directly and received open-label adalimumab at 0.8 mg/kg eow for up to 52 weeks. Participants who responded in Period A entered the Treatment Withdrawal Phase (Period B) for up to 36 weeks. Participants who experienced a loss of disease control in Period B entered the Re-treatment Phase (Period C) and received blinded adalimumab 0.8 mg/kg eow for 16 weeks. Participants who completed Period B with no loss of disease control entered Period D and were observed off study medication for up to 52 weeks. Participants who completed Period C entered Period D for an additional 52 weeks of treatment with blinded adalimumab 0.8 mg/kg eow.