A 36-year-old patient with ulcerative colitis (UC) underwent total proctocolectomy with ileal pouch anal anastomosis (IPAA) 3 years ago. The patient presents now with lower abdominal discomfort that is associated with bloody loose stools. Endoscopy shows erythematous friable rectal cuff with deep ulcers. The rest of the pouch appears normal. What is the most appropriate treatment?