Anaphylaxis-like reaction to anti-BRAF inhibitor dabrafenib confirmed by drug provocation test

Area of Science:

• Oncology
• Immunology
• Pharmacology

Background:

• BRAF and MEK inhibitors represent a standard therapy for metastatic melanoma with BRAF mutations, improving survival with manageable toxicity.
• Severe toxicities, including anaphylaxis-like reactions, have been rarely reported with these targeted therapies.
• Previous reports lacked confirmatory diagnostic testing for suspected hypersensitivity reactions.

Observation:

• This case report details a patient experiencing an anaphylactic reaction to dabrafenib, a BRAF inhibitor, during first-line treatment.
• The patient presented with severe hypotension, a distinct clinical manifestation from previously reported cases.
• Diagnostic assessment included a drug provocation test (gold standard), serum tryptase levels, and an in-vitro basophil activation test.

Findings:

• The drug provocation test confirmed hypersensitivity to dabrafenib.
• Both IgE-mediated and non-IgE-mediated reaction elements were observed, suggesting a complex pathomechanism.
• The findings indicate a potential for heterogeneous clinical manifestations in immediate hypersensitivity reactions to BRAF inhibitors.

Implications:

• This case underscores the importance of diagnostic testing for suspected drug hypersensitivity reactions to targeted cancer therapies.
• The observed complex pathomechanism may explain the varied clinical presentations of anaphylaxis to BRAF inhibitors.
• Further molecular and cellular studies are warranted to elucidate the mechanisms underlying these severe hypersensitivity reactions.