To do or not to do: A concise update of current clinical controversies in immune checkpoint blockade.

Although programmed death-ligand 1 is currently the best available biomarker for first-line therapy with pembrolizumab for patients with non-small cell lung cancer and is a required companion test approved by the US Food and Drug Administration, programmed death-ligand 1 testing is an option (as a complementary test) for patients treated with nivolumab, atezolizumab, and durvalumab. Programmed death-ligand 1 expression is continuously variable and dynamic in the tumor microenvironment. Due to the complex molecular and cellular interactions involved in immune response, a single biomarker may not be sufficient to predict response to cancer immunotherapy. Integration of multiple tumor, immune response, and genomic parameters is likely to influence the future interpretation of biomarker-based treatment outcomes. This article, in a case-based format, concisely summarizes most up-to-date evidence in answering some commonly seen clinical controversies of cancer immunotherapy, in terms of (i) the predictive value of programmed death-ligand 1 as a biomarker; (ii) whether the use of steroids with checkpoint inhibitors will decrease efficacy of the latter; (iii) selection of patients for cancer immunotherapy based on immune-based response criteria, and (iv) whether the use of influenza vaccine with checkpoint inhibitors is considered safe. Until more robust, long-term prospective clinical data are available, these discussions may serve as a starting point for pharmacists to gain timely and effective management of these realistic issues.