A 35-year-old woman from Bangalore presents with a 2-year history of intermittent diarrhea, right lower quadrant pain, and weight loss. Colonoscopy reveals skip lesions with cobblestone appearance and aphthous ulcers in the terminal ileum. Biopsy shows transmural inflammation with non-caseating granulomas. She has erythema nodosum on the shins. Laboratory studies show elevated inflammatory markers and normal albumin. She has not received any immunosuppressive therapy. What is the most appropriate next step in management?