This is a Rheumatoid Arthritis (RA) study. The purpose of this research study is to determine in RA flare, whether musculoskeletal ultrasound (MSUS) inflammatory scores and/or disease activity scores improve with Acthar treatment.

Participants with active RA flair will be assigned to take on one of two Acthar doses, either 40 units per week or 80 units twice a week. Both arms will be taking the drug for 4 weeks. Each participant will be coming back for visits at 2 weeks, 1 month and 3 months after the initial baseline visit. During these visits the following information will be collected: MSUS of joints, DAS28, Clinical Disease Activity Index (CDAI), Routine Assessment of Patient Index Data 3 (RAPID3) and Health Assessment Questionnaire-Disability Index (HAQ-DI). Participants will also be asked to fill out a questionnaire about their health status.

Efficacy of Acthar to decrease evidence of MSUS synovitis and disease activity measures will be analyzed using the above mentioned instruments, as well as Acthar's ability to prevent the necessity to change patients' RA treatment regimen.

Inclusion Criteria:

1. Patient must meet 1987 ACR criteria
2. Age > 18 years of age
3. Baseline DAS28/Erythrocyte Sedimentation Rate (ESR) >=3.2
4. Stable concomitant Disease Modifying Anti-Rheumatic Drugs (DMARDs)
5. Stable prednisone <10mg or equivalent
6. Power Doppler score of >=10

Exclusion Criteria:

1. Prior treatment with Acthar in the past 2mos
2. Meet one of the above RA flare requirements
3. Subjects who have received live or live attenuated vaccines within 6 weeks prior to the first dose of study drug (or the zoster vaccine)