Background: 5% of patients with non-small-cell lung cancer (NSCLC) have a translocation of the ALK (anaplastic lymphoma kinase) gene on chromosome 2. The phase III clinical trial (ALEX study) analyzed the efficacy and safety in patients with a diagnosis of NSCLC and ALK mutation -positive (ALK+) randomized to alectinib versus crizotinib. The objective of our study is to describe our results with alectinib. Methods: Observational and descriptive study of patients with advanced NSCLC and ALK+ treated with alectinib in the period 2019-2022. Sociodemographic and clinical variables, toxicity profile, objective response rate (ORR), treatment response and progression free survival (PFS) were extracted and entered into IBM SPSS Statistics 22 for statistical analysis. Results: 7 patients received treatment. The median age was 46 years. Baseline characteristics: male (57%); non- Asian race (100%); non-smoker (57%), ECOG 0-1 (100%). All had adenocarcinoma histology. 57% had liver metastasis and 37% central nervous system metastasis at the time of diagnosis. The most frequent symptom was dyspnea (43%). Only one patient was previously terated with 2 lines of chemotherapy and a 3rd line with crizotinib prior to alectinib. Adjuvant chemotherapy was administered in one patient. The rest of the participants received alectinib as first line. The most frequent toxicities were: grade 1-2 increased alanine and aspartate aminotransferase (70%); grade 1 anemia (28.6%); grade 1 increased blood bilirubin (28.6%), skin toxicities (71.5%), myalgia (57%), visual disorders (28.6%); constipation (28.6%) and sinus bradycardia (14.5%). A 28.6% incidence of dose reductions due to adverse events (AEs) with alectinib. One patient had to discontinue treatment with alectinib due to grade 4 AEs consisting of toxic pneumonitis.Hospital admission was required. The ORR was 57.2%. Complete response ocurred in 28.6% of patients. The median response to treatment was 16 months and the median PFS was 16 months. Conclusions: The sociodemographic characteristics of our patients were similar to those described in the ALEX trial. However, the AEs were higher in our study. The ORR was lower in our study, despite obtaining a high percentage of complete responses. We have a reduced number of patients who have been treated with alectinib to obtain final conclusions efficacy.