Pembrolizumab Induced Calcitriol-Mediated Hypercalcemia.

Area of Science:

• Oncology
• Immunology
• Nephrology

Background:

• Programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors, such as pembrolizumab, have transformed advanced cancer treatment.
• While effective, these immunotherapies can cause immune-related adverse events (irAEs).
• Early identification and management of irAEs are crucial for patient outcomes.

Observation:

• A unique clinical syndrome was observed in a patient receiving pembrolizumab.
• This syndrome presented with hypercalcemia, acute kidney injury, and hypoxic respiratory failure.
• These symptoms were responsive to corticosteroid treatment.

Findings:

• The observed syndrome suggests a potential form of immunotoxicity directly related to pembrolizumab therapy.
• The constellation of hypercalcemia, renal injury, and respiratory compromise represents a distinct irAE pattern.
• Corticosteroid administration demonstrated therapeutic efficacy, supporting an immune-mediated mechanism.

Implications:

• This case highlights the importance of recognizing novel irAEs associated with PD-1/PD-L1 inhibitors.
• Prompt diagnosis and intervention, including prompt corticosteroid use, may improve outcomes for patients experiencing severe irAEs.
• Further research is warranted to elucidate the mechanisms underlying this specific pembrolizumab-induced syndrome.