Facultad de Ciencias de la Salud

We describe a clinical case of an 84-year-old man diagnosed with non-small cell lung carcinoma and epidermal growth factor receptor mutation, who was treated with erlotinib, with doses adjusted by therapeutic drug monitoring. This case involved a clearance fluctuation leading to over-therapeutic drug concentrations of erlotinib and toxicity. The intrapatient and interpatient variability of erlotinib, in addition to other factors such as age or variations in liver clearance, create situations that are challenging in clinical practice. During treatment, erlotinib serum concentrations were measured, and the dose was accordingly adjusted. The erlotinib dose required to reduce toxicity (rash grade III) and maintain effective plasma concentrations, as well as clinical and radiological responses, was 50% of the initial dose, underscoring the relevance of therapeutic drug monitoring for tyrosine kinase inhibitors in routine clinical practice.

Discovery and clinical development of monoclonal antibodies with the ability to interfere in the regulation of the immune response have significantly changed the landscape of oncology in recent years. Among the active agents licensed by the regulatory agencies, nivolumab and pembrolizumab are paradigmatic as the most relevant ones according to the magnitude of available data derived from the extensive preclinical and clinical experience. Although in both cases the respective data sheets indicate well-defined dosage regimens, a review of the literature permits to verify the existence of many issues still unresolved about dosing the two agents, so it must be considered an open question of potentially important consequences, in which to work to improve the effectiveness and efficiency of use.