Durvalumab-Induced Hypoparathyroidism

There have been more reported immune-related adverse events with increasing use of immune checkpoint inhibitors (ICIs) in the treatment of cancers. A range of endocrinopathies have been reported; however, ICI-induced hypoparathyroidism remains a rare immune-related adverse event. The objective of this report is to describe a rare case of durvalumab-induced hypoparathyroidism.

We describe a case of a 64-year-old man who presented to the emergency department with acute symptomatic hypocalcemia 2 years after completion of durvalumab treatment for stage III non-small cell lung cancer, who had a suppressed parathyroid hormone level, which persisted with correction of calcium levels.

ICI-induced hypoparathyroidism is a rare entity with only few cases reported in the literature, the mechanism for which remains unclear. Persistence of hypoparathyroidism despite discontinuation of immunotherapy makes inflammation and immune-mediated destruction a possible explanation.

This case reinforces the need for an increased awareness and recognition of durvalumab-induced hypoparathyroidism, in addition to more investigation into its underlying mechanisms and potential management options.