Thrombocytopenia during avacopan administration: A case report

Area of Science:

• Immunology
• Pharmacology
• Nephrology

Background:

• Avacopan is a novel C5a receptor antagonist approved for treating microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA).
• Thrombocytopenia is a potential adverse effect of various medications, necessitating vigilance in clinical practice.

Observation:

• A 78-year-old male with MPA developed rapidly progressive glomerulonephritis and vasculitis neuropathy.
• Treatment with corticosteroids was initiated, followed by avacopan to reduce corticosteroid dosage.
• Within a week of starting avacopan, the patient experienced a significant decrease in platelet counts.

Findings:

• Avacopan was identified as the probable cause of thrombocytopenia, as platelet counts normalized after drug cessation.
• Other potential causes, such as thrombotic microangiopathy and heparin-induced thrombocytopenia, were ruled out.
• This represents the first reported case of avacopan-induced thrombocytopenia.

Implications:

• Highlights the importance of postmarketing surveillance for identifying rare adverse events associated with new drugs like avacopan.
• Clinicians should closely monitor platelet counts in patients treated with avacopan to ensure patient safety.
• Further research may be warranted to elucidate the mechanism of avacopan-induced thrombocytopenia.