Oral exemestane 25 mg/day for 2–3 years of adjuvant therapy was generally more effective than 5 years of continuous adjuvant tamoxifen in the treatment of postmenopausal women with early-stage estrogen receptor-positive/unknown receptor status breast in a large well-designed [ citation needed ] trial. Preliminary data from the open-label TEAM trial comparing exemestane with tamoxifen indicated in 2009 that exemestane 25 mg/day is also effective in the primary adjuvant treatment of early-stage breast cancer in postmenopausal women. 
A 47 year old postmenopausal woman with estrogen receptor positive breast cancer developed fatigue, followed by pruritus and jaundice 3 weeks after starting adjuvant therapy with exemestane (25 mg daily). She had no history of liver disease, risk factors for viral hepatitis or alcohol abuse. She had no history of drug allergies and her only other medication was naproxen (550 mg), taken intermittently for a sports related wrist injury. On presentation, serum bilirubin was mg/dL, ALT 438 U/L, AST 170 U/L and alkaline phosphatase 181 U/L. These were known to have been normal in the past (Table). Tests for hepatitis A, B and C were negative as were autoantibodies. Despite stopping exemestane, jaundice worsened, and she developed intractable pruritus for which she was hospitalized and treated with ursodiol, cholestyramine, phenobarbital, lorazepam and venlafaxine. She slowly improved, but still had minor elevations in serum enzyme 6 months after stopping exemestane.
Additional adverse reactions of any cause observed in the overall clinical trials program (N = 1058) in 5% or greater of patients treated with exemestane 25 mg once daily but not in the comparative study included pain at tumor sites (8%), asthenia (6%), and fever (5%). Adverse reactions of any cause reported in 2% to 5% of all patients treated with exemestane 25 mg in the overall clinical trials program but not in the comparative study included chest pain, hypoesthesia, confusion, dyspepsia , arthralgia, back pain, skeletal pain, infection, upper respiratory tract infection, pharyngitis , rhinitis , and alopecia.