Real-world outcomes in a Latin American setting with first-line osimertinib in EGFR-mutated NSCLC.

Background: In non-small cell lung cancer (NSCLC), mutations in the epidermal growth factor receptor (EGFR) represent a significant therapeutic target. Osimertinib, a third-generation TKI, has demonstrated superior efficacy, safety, and CNS activity in clinical trials compared to earlier generations, becoming the preferred first-line treatment for EGFR-mutated NSCLC. However, real-world outcomes may differ substantially from clinical trial results due to healthcare system challenges, including delays in diagnosis, treatment initiation, drug access, and follow-up care. Colombia’s healthcare system is a two-tiered structure with contributory and subsidized regimes. Disparities between these systems often result in inequities in cancer care, particularly affecting vulnerable populations with limited access to specialized services. We therefore aim to assess the real-world benefit of Osimertinib in Colombia. Methods: This is a retrospective cohort study analyzing EGFR-mutated lung adenocarcinoma patients treated with Osimertinib in Colombia. Data from electronic medical records was collected in REDCap. Overall survival was calculated from Osimertinib initiation until death/last follow-up using Kaplan-Meier methodology. Analyses were performed in R 4.2.2 using survival and survminer packages, with variables evaluated through appropriate parametric and non-parametric tests. Results: The study included 18 patients, with a median age of 68.4 years (SD 9.6). Most had good performance status (ECOG 0-1: 72.2%, mean Karnofsky 81.7) and stage IV disease (83.4%, n=15). The median time from prescription to treatment initiation was 16.5 days (IQR 11.0–26.5). Delays exceeding 26.5 days were observed in four patients, with a maximum delay of 49 days. Despite these challenges, the 12- and 24-month OS rates were 100% and 92.9%, respectively. Only one death occurred at 12.2 months post-treatment initiation, and the median survival was not reached. Outcomes were consistent across early (≤16.5 days) and delayed (>16.5 days) treatment initiation groups (p=0.28). Conclusions: First-line Osimertinib demonstrates remarkable effectiveness in EGFR-mutated NSCLC in this real-world setting, achieving a 92.9% 24-month OS rate despite delays in treatment initiation. However, interpretation is limited by the small sample size and missing follow-up data for three patients. These outcomes underscore inequities in healthcare access, as systemic delays and barriers to innovative treatments may disproportionately affect underserved populations different from that seen at our center. Our findings highlight the need for structural improvements in the Colombian healthcare system to ensure timely and effective treatment delivery across all socioeconomic groups.