Treatment of rheumatoid arthritis (RA) to provide clinical benefit in patients, including decrease in DAS28-CRP by more than 1.2 and/or improvement determined by ACR20, ACR50 or ACR70, comprising administering therapeutic antibody mavrilimumab or other inhibitor targeted to Tyr-Leu-Asp-Phe-Gln motif of granulocyte/macrophage colony stimulating factor receptor alpha (GM-CSFRα). Use of GM-CSFRα inhibitors such as mavrilimumab to enhance clinical benefit in RA patients receiving stable dose of DMARDs, particularly methotrexate.