In this double-blind , phase 3 study , 606 patients with psoriatic arthritis were randomly assigned in a 1:1:1 ratio to receive intravenous secukinumab ( at a dose of 10 mg per kilogram ) at weeks 0 , 2 , and 4 , followed by subcutaneous secukinumab at a dose of either 150 mg or 75 mg every 4 weeks , or placebo .