A 58-year-old female patient without disease history of diabetes mellitus was enrolled in the phase Ⅲ clinical trial of alpelisib combined with fulvestrant due to ineffective treatment of stage Ⅳ breast cancer. The treatment regimen was alpelisib tablets 300 mg orally once daily and fulvestrant injection 500 mg once a month intramuscularly. One month later, the patient experienced symptoms such as poor appetite, nausea, vomiting, drowsiness, and blurred consciousness. Laboratory tests showed arterial blood pH 7.1, random blood glucose >34.7 mmol/L, serum creatinine 210 μmmol/L, blood potassium 3.00 mmol/L, blood sodium 129 mmol/L, and urine ketone body (++). Diabetic ketoacidosis was diagnosed, and treatments such as intravenous insulin supplementation, rehydration, and correction of acidosis and electrolyte disorders were given. After 5 days, the patient′s symptoms were improved, but the blood glucose was poor controlled. Diabetic ketoacidosis was considered to be related to alpelisib. The dose of alpelisib was reduced by half, oral hypoglycemic drugs were added, and the insulin regimen was adjusted. Later, the blood glucose was relatively well controlled, and urinary ketone bodies turned negative.

A 58-year-old female patient without disease history of diabetes mellitus was enrolled in the phase Ⅲ clinical trial of alpelisib combined with fulvestrant due to ineffective treatment of stage Ⅳ breast cancer. The treatment regimen was alpelisib tablets 300 mg orally once daily and fulvestrant injection 500 mg once a month intramuscularly. One month later, the patient experienced symptoms such as poor appetite, nausea, vomiting, drowsiness, and blurred consciousness. Laboratory tests showed arterial blood pH 7.1, random blood glucose >34.7 mmol/L, serum creatinine 210 μmmol/L, blood potassium 3.00 mmol/L, blood sodium 129 mmol/L, and urine ketone body (++). Diabetic ketoacidosis was diagnosed, and treatments such as intravenous insulin supplementation, rehydration, and correction of acidosis and electrolyte disorders were given. After 5 days, the patient′s symptoms were improved, but the blood glucose was poor controlled. Diabetic ketoacidosis was considered to be related to alpelisib. The dose of alpelisib was reduced by half, oral hypoglycemic drugs were added, and the insulin regimen was adjusted. Later, the blood glucose was relatively well controlled, and urinary ketone bodies turned negative.