In a substudy of a randomised , double-blind , phase 3b study ( ACT-RAY ) of biologic-nave patients with RA who were methotrexate ( MTX ) - inadequate responders , 63 patients were randomised to continue MTX or receive placebo ( PBO ) , both in combination with TCZ 8 mg/kg every 4 weeks , with optional additional disease-modifying antirheumatic drugs at week 24 if Disease Activity Score of 28 joints < 3.2 .