A 38-year-old woman with a 4-year history of seropositive RA (RF+, anti-CCP+) on methotrexate 20 mg weekly presents with persistent joint swelling and pain affecting her hands, wrists, knees, and ankles despite 6 months of therapy. Her DAS28 score is 5.8. She has developed a firm, non-tender nodule over the extensor surface of her right elbow. ESR is 52 mm/hr, CRP 8.5 mg/dL. X-rays show progression of erosions compared to 1 year ago. What is the most appropriate next step?