TOXICITIES OF TARGETED THERAPY AND IMMUNE-RELATED ADVERSE DRUG REACTIONS OF IMMUNOTHERAPY IN THE TREATMENT OF METASTATIC MELANOMA

Abstract

Targeted therapy and immunotherapy changed the treatment landscape for metastatic melanoma, which is chemotherapy resistant cancer. In pre-innovation era, the overall survival of patients with metastatic melanoma was 6 months, while today 5-year overall survival rate of 34% (and 50% in good prognostic groups) is evident. However, both treatments have their side effects, and cutaneous are the most frequent. Treating physicians in oncology centres, but also primary care specialists, need to be aware of their spectrum which differs for each class of drug: BRAF inhibitors, MEK inhibitors and immunotherapy with anti-PD1 and anti-CTLA4. While BRAF inhibitors have the most prominent adverse effects which are class specific, there are also drug-specific adverse effects. For example, vemurafenib causes photosensitivity, which is not specific for dabrafenib, while dabrafenib induces pyrexia, that occurs much less frequently with other BRAF inhibitors. Cutaneous rash and cutaneous neoplasms which develop due to paradoxical activation of RAS signalling are described with BRAF inhibitor monotherapy. These side-effects are much less common in combination therapy with BRAF and MEK inhibitor, but MEK inhibitor itself causes characteristic acneiform eruption, and serous retinopathy. Immune related adverse drug reactions are a hallmark of the immune checkpoint inhibitor immunotherapy, which can affect every organ system, and most commonly skin, lungs and gastrointestinal system, with differential frequencies recorded with anti-CTLA4 therapy and anti PD-1 therapy. Skin reactions most frequently include pruritus and eczematous reactions, as well as vitiligo-like hypopigmentation, which is linked Melanom 45 to the better response to treatment. In this review, frequent and rare side effects are presented, as well as the current algorithms for their treatment.