A Safety and Efficacy Study of Ustekinumab in Patients With Plaque Psoriasis Who Have Had an Inadequate Response to Methotrexate

Patients weighting ≤ 100 kg will receive ustekinumab 45 mg at Weeks 0, 4 and 16. Patients who achieve a PASI 75 response at Week 28 and 40 will continue receiving ustekinumab 45 mg at Week 28 and 40. Patients who fail to achieve PASI 75 response at Week 28 will receive ustekinumab 90 mg at Week 28 and 40. Patients who achieve a PASI 75 response at Week 28, but fail to achieve PASI 75 response at Week 40 will receive ustekinumab 90 mg at Week 40. Patients \> 100 kg will receive ustekinumab 90 mg at Weeks 0, 4, 16, 28 and 40, regardless of achievement of PASI 75 response. Consideration will be given to discontinuing treatment in these patients if they show no response at Week 28.

Gradual reduction of methotrexate therapy over the 4 week period after Week 0. The methotrexate dose reduction regime will depend on the dose of methotrexate at screening. All patients will stop methotrexate regardless of the final dose after 4 overlapping weeks. The last dose of methotrexate will be given within the 7 day period before the second dose of ustekinumab.