Rama Koneru^1,, Jahnavi Mundluru², Abdul Subhan³

Melanoma is the third most prevalent skin cancer with the highest mortality rate amongst skin cancers. Recent therapeutic developments have improved its treatment options, however significant toxicity can be a limiting factor. In this report, we describe a case of a rare, delayed hypersensitivity-like reaction after treatment with dabrafenib-trametinib as a second line therapy in a metastatic melanoma patient treated with pembrolizumab initially. A 62-year-old Caucasian male presented with a left axillary mass, which was found to be BRAF V600E positive malignant melanoma upon biopsy. He proceeded to have full axillary node dissection and was scheduled to receive adjuvant immunotherapy with pembrolizumab. However, the treatment was delayed by 3 weeks due to COVID-19. The patient developed subcutaneous metastases within that time. Although he was started on pembrolizumab, the metastases continued to progress. The patient then opted to begin dabrafenib-trametinib and was started on full dose therapy. After two weeks, there was significant reduction of metastases clinically. Two days after the follow-up, he presented to the emergency room with diffuse non-pruritic hives all over the body without any symptoms of angioedema. In addition, there was a sudden increase in size of the subcutaneous metastases. He was treated with 50 mg Benadryl and 50 mg prednisone with almost immediate resolution and discharged on prednisone. Dabrafenib-trametinib was temporarily discontinued. Due to the limited treatment options, the patient was carefully restarted on his dabrafenib-trametinib regimen with slow prednisone tapering. Patient has had an excellent response with complete resolution of his disease with no measurable lesions found on the latest CT scan. After a thorough literature search of OVID Medline + EMBASE, it was concluded that this is a rare presentation and only a few similar cases have been reported. Therefore, health care provider education and strategies for reintroduction of immunotherapy, as presented through a prednisone regimen in this case, is imperative for proper management of adverse events.

melanoma, adverse events, immunotherapy strategies, PD-1 inhibitor, BRAF/MEK inhibitor, case report