Drug-induced hypersensitivity syndrome like reaction with angioedema and hypotension associated with BRAF inhibitor use and antecedent immune checkpoint therapy

Drug-Induced Hypersensitivity Syndrome (DIHS)/Drug Reaction With Eosinophilia and Systemic Symptoms (DRESS): Clinical Features and Pathogenesis

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS) is one example of a severe delayed T-cell-mediated adverse drug reaction. DIHS/DRESS presents with fever, widespread rash and facial edema, organ involvement, and hematological abnormalities, including eosinophilia and atypical lymphocytosis. DIHS/DRESS is associated with relapse 2 to 4 weeks after acute symptoms, often coinciding with reactivation of prevalent chronic persistent human herpesviruses such as human herpesvirus 6, EBV, and cytomegalovirus. The mortality of DIHS/DRESS is up to 10% and often related to unrecognized myocarditis and cytomegalovirus complications, with longer-term consequences that contribute to morbidity including autoimmune diseases such as thyroiditis. It is essential that all potential drug causes, including all new drugs introduced within the 8 weeks preceding onset of DIHS/DRESS symptoms, are identified. All potential drug culprits, as well as drugs that are closely related structurally to the culprit drug, should be avoided in the future. Systemic corticosteroids have remained the mainstay for the treatment of DIHS/DRESS with internal organ involvement. Steroid-sparing agents, such as cyclosporine, mycophenolate mofetil, and monthly intravenous immune globulin, have been successfully used for treatment, and careful follow-up for cytomegalovirus reactivation is recommended. Strong associations between HLA class I alleles and DIHS/DRESS predisposition include HLA-B∗13:01 and dapsone, HLA-B∗58:01 and allopurinol, and HLA-B∗32:01 and vancomycin. These have opened a pathway for prevention, risk stratification, and earlier diagnosis. Single-cell sequencing and other studies of immunopathogenesis promise to identify targeted treatment approaches.

Successful Dabrafenib Desensitization Protocols in a Patient with Metastatic Melanoma

Dabrafenib and trametinib are two available molecules that have been approved for the treatment of metastatic melanoma with BRAF-V600E or V600K mutations. Their combined therapy has led to long-lasting survival benefits and substantially improved outcomes. Until now, only a few cases of severe hypersensitivity reactions to dabrafenib and vemurafenib have been reported, and even fewer desensitization protocols to these molecules have been documented. We report the case of a 71-year-old female patient with metastatic melanoma harboring a BRAF-V600E mutation undergoing targeted therapy with dabrafenib and trametinib. Two weeks after the initiation of the combined treatment, she developed a hypersensitivity reaction. The cause–effect relationship between dabrafenib and the hypersensitivity reaction was demonstrated twice, when symptoms recurred upon dabrafenib reintroduction. We started a rapid 3-day dabrafenib desensitization protocol, which was well tolerated. When the patient discontinued the drug administration, we decided on a longer protocol that included more steps and more days in order to prevent the occurrence of other hypersensitivity reactions. Our patient tolerated both rapid and slow-going schedules, the first one reaching the final dose within 3 days and the second one reaching the total daily dose within 14 days. Depending on the patient’s needs, the severity of the hypersensitivity reaction and the hospital’s availability, the doctor may choose either the rapid or slow-going desensitization protocol.