1 │ INTRODUCTION
BRAFV600E mutations occur in 5% to 16% of
pediatric patients with pilocytic astrocytoma, which is the most common
type of pediatric brain tumor. This alteration is associated with high
recurrence rates, despite conventional chemotherapy, and poor
progression-free survival.1–3 The
BRAFV600E inhibitors vemurafenib and dabrafenib have
demonstrated considerable promise for pediatric patients with
relapsed/refractory gliomas harboring theBRAFV600E mutation.4 However,
hypersensitivity reactions, such as cutaneous reactions to
BRAFV600E inhibitors, are common, even in pediatric
patients.5,6 If cutaneous reactions are severe, this
leads to permanent discontinuation of a potentially life-saving therapy.
Vemurafenib and dabrafenib share similar chemical structures, including
a sulfonamide group.5 Cross-reactivity between BRAF
inhibitors and other sulfonamides may contribute to their
intolerance.5 Hypersensitivity reactions to
BRAFV600E inhibitors followed by tolerance to another
BRAFV600E inhibitor is rarely described, especially
for pediatric patients. To date, successful transition from one
BRAFV600E inhibitor to another is reported in only one
pediatric case of anaplastic ganglioglioma and in three adult cases of
melanoma.7–10 Here, we describe an immediate
hypersensitivity reaction to vemurafenib in a pediatric patient with a
pilocytic astrocytoma. We then administered a desensitization regimen
with dabrafenib and trametinib, which yielded a positive tumor response
without further allergic reaction.