Article ID: EJ26-0035
Capivasertib, an oral pan-AKT inhibitor, is a therapeutic option for hormone receptor-positive advanced breast cancer. While hyperglycemia is a recognized adverse effect of AKT inhibition, its diagnosis is often delayed in routine clinical practice. We report a case of acute-onset severe hyperglycemia with diabetic ketosis identified within 4 days of initiating capivasertib in a patient without pre-existing glucose intolerance. A 61-year-old woman developed marked hyperglycemia (random plasma glucose, 482 mg/dL) with ketosis, despite being asymptomatic. Laboratory evaluation showed markedly elevated serum insulin (591.9 μU/mL), indicating preserved pancreatic β-cell function and severe insulin resistance. Blood glucose levels improved rapidly within 2 days of admission using minimal insulin therapy and fluid replacement. Unlike previously reported cases identified after symptomatic presentation, including emergency department visits, or under intensive inpatient monitoring, this case was detected through a proactively scheduled outpatient visit on day 4—strategically timed to coincide with the end of the first dosing cycle based on the drug’s pharmacological profile. This observation highlights that severe hyperglycemia can develop very early and remain asymptomatic, underscoring the importance of proactive detection. Therefore, even in patients without pre-existing glucose intolerance or with preserved insulin secretion, proactive glucose monitoring during the first week of therapy, specifically near the end of the initial dosing cycle, is essential to prevent severe metabolic complications. Appropriate patient education and early consultation with diabetes specialists are also crucial for timely management.
