Cutaneous type IV hypersensitivity reaction following tebentafusp treatment for uveal melanoma

Tebentafusp is a bispecific protein that recently underwent FDA approval for the treatment of metastatic uveal melanoma that functions by redirecting cytotoxic T cells to glycoprotein-100, a protein highly expressed in melanoma. Although clinical trials have demonstrated that rashes are common in the first few days of treatment, little is known about skin reactions that develop later in the treatment course. Herein, we describe a type IV hypersensitivity reaction and vitiligo-like depigmentation that developed six weeks into treatment and discuss the possible mechanisms underlying these reactions. The type IV hypersensitivity reaction resolved without intervention within seven weeks of onset, suggesting that tebentafusp can be safely continued in select patients who develop this cutaneous reaction.