Conference Coverage

Diabetes from checkpoint inhibitors probably means lifelong insulin



Cancer patients don’t necessarily have to come off immune checkpoint inhibitors if they develop diabetes, according to Priyanka Iyer, MD, an endocrinology fellow at MD Anderson Cancer Center, Houston.

“As long as we get glycemic control, they can continue,” she said at the annual meeting of the Endocrine Society.

Diabetes is a known side effect of immune checkpoint inhibitors (ICIs) but it’s rare, occurring in maybe 0.17% of patients, and its natural history and risk factors are unknown.

Dr. Priyanka Iyer, an endocrinology fellow at MD Anderson Cancer Center, Houston

Dr. Priyanka Iyer

To get a handle on the problem, Dr. Iyer described 24 cases at MD Anderson, the largest single-center series to date. The hope is to one day create screening and management guidelines.

ICIs are fairly new agents, and as their use expands beyond clinical trials, “we anticipate seeing larger numbers of cases. Patients should be educated about the symptoms of uncontrolled blood sugars while on ICIs,” and endocrinologists “have to get involved and recognize this entity sooner,” Dr. Iyer said.

In short, her team found that ICI-mediated diabetes can occur in patients with or without preexisting diabetes, and that most patients have evidence of beta-cell failure, likely T-cell mediated destruction due to immune activation. In all but one case, patients remained on insulin at a median follow-up of 44 weeks, even after stopping ICIs. For most, ICI-mediated diabetes likely means lifelong insulin.

They were all on the programmed cell death protein (PD-1) inhibitors nivolumab (Opdivo) or pembrolizumab (Keytruda), or the PD-1 ligand (PD-L) inhibitor durvalumab (Imfinzi). The agents are used for a range of cancers, including renal cell, melanoma, and Hodgkin lymphoma. There were no diabetes cases in patients on single-agent ipilimumab (Yervoy) or tremelimumab, which target cytotoxic T-lymphocyte associated antigen-4 and are used for melanoma and mesothelioma.

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