Study of LX3305 in Subjects With Active Rheumatoid Arthritis on Stable Methotrexate

ACR50 Response at Week 12

Evaluates the efficacy of LX3305 by utilizing the American College of Rheumatology 50% response criteria (ACR50) at 12 weeks in subjects with active RA also receiving stable doses of MTX. For a response of ACR50, there had to be ≥50% improvement in swollen joint count, ≥50% improvement in painful/tender joint count, and ≥50% improvement in at least 3 of the following: subject's assessment of pain, global assessment of disease activity, assessment of physical function, or acute phase reactant (C-reactive protein or erythrocyte sedimentation rate).

Time frame: Baseline and 12 weeks

ACR70 Response at Week 12

Evaluates the efficacy of LX3305 by utilizing the American College of Rheumatology 70% response criteria (ACR70) at 12 weeks in subjects with active RA also receiving stable doses of MTX. For a response of ACR70, there had to be ≥70% improvement in swollen joint count, ≥70% improvement in painful/tender joint count, and ≥70% improvement in at least 3 of the following: subject's assessment of pain, global assessment of disease activity, assessment of physical function, or acute phase reactant (C-reactive protein or erythrocyte sedimentation rate).

Time frame: Baseline and 12 weeks

Hybrid ACR Response at Week 12

Evaluates the improvement in active RA by combining elements of the ACR20/50/70 with a continuous score of the mean change in core set measures. The percentage improvement from baseline was computed in each of the components of the ACR. The average percent improvement was calculated and used with the subject's ACR20, ACR50, and ACR70 status to compute the hybrid ACR response, with a positive change indicating improvement.