Safety of pembrolizumab for the treatment of melanoma

INTRODUCTION: The immune checkpoint inhibitor pembrolizumab is the first anti-programmed-death-1 (PD-1) drug licensed by the FDA. It has been approved for the treatment of advanced melanoma, thanks to its positive results in terms of efficacy and its favorable toxicity profile. However, it is not exempt from side effects. In general, these are usually mild and easily manageable but there are pembrolizumab-induced immune-related adverse events (irAEs) that can be severe. Therefore, the understanding, diagnosis and management of those side effects are essential for the optimal care of patients treated with pembrolizumab. AREAS COVERED: In this article, the safety and efficacy of pembrolizumab in melanoma are extensively reviewed as well as its mechanism of action and the role of the PD-1 pathway in cancer. Also, its profile of side effects is compared with other immune checkpoint inhibitors such as ipilimumab and nivolumab. EXPERT OPINION: Pembrolizumab is generally a well-tolerated drug but irAEs are not infrequent. However, these are usually mild and easily manageable in most cases. Early diagnosis and correct management of side effects induced by immune checkpoint inhibitors such as pembrolizumab should be areas of further work in forthcoming years.