Can immune checkpoint inhibitors cause diabetes mellitus in patients?

Immune checkpoint inhibitors (ICIs) are powerful cancer treatments that work by unleashing the immune system against tumors. However, this immune activation can sometimes mistakenly attack the body's own tissues, leading to side effects called immune-related adverse events. One such side effect is diabetes mellitus, which can develop rapidly and may be severe. This condition, known as ICI-induced diabetes mellitus (ICI-DM), often resembles type 1 diabetes and requires prompt recognition and treatment.

What the research says

ICI-DM is a relatively uncommon but serious complication of immunotherapy. It typically occurs within the first three months after starting treatment, but delayed cases have been reported, even after treatment is stopped ¹. The condition often presents with diabetic ketoacidosis (DKA), a life-threatening emergency ¹¹⁰¹¹. ICI-DM is characterized by rapid onset and usually leads to permanent insulin dependence ¹⁰¹¹. The exact mechanisms are not fully understood, but it involves autoimmune destruction of insulin-producing beta cells in the pancreas ⁹¹¹. While most cases require lifelong insulin therapy, some patients may continue immunotherapy with careful glucose monitoring ¹.

What to ask your doctor

• What are the signs of high blood sugar or diabetic ketoacidosis that I should watch for during immunotherapy?
• How often should my blood sugar be checked while on immune checkpoint inhibitors?
• If I develop diabetes from treatment, can I continue immunotherapy?
• What is the plan for managing diabetes if it occurs, including insulin therapy?
• Are there any factors that might increase my risk for this side effect?