Jaller, Elvira

e20761 Background: The prognostic role of serial circulating tumor DNA (ctDNA) dynamics during osimertinib treatment has been described mainly in Asian and European populations; however, it remains poorly defined in Hispanic patients with advanced EGFR-mutant non–small cell lung cancer (NSCLC). Our aim was to determine whether serial plasma EGFR testing identifies patients at high risk of early mortality. Methods: This multicenter, retrospective study included 64 Hispanic patients with stage IIIB–IV EGFR-mutant NSCLC treated with first-line osimertinib between 2018 and 2023. Tumor tissue genotyping was performed using hybrid-capture next-generation sequencing. Plasma EGFR mutations were assessed at baseline, week 8, and week 24. Overall survival (OS) and progression-free survival (PFS) were analyzed using Cox models adjusted for p53 status, RAF-pathway alterations, and metastatic burden. Results: The cohort had a median age of 61 years, with 65.6% of patients being female and 56.2% being never-smokers. Sensitizing EGFR mutations consisted mainly of exon 19 deletion (59.4%) and L858R (39.1%). Relevant co-mutations were identified in TP53 (29.7%) and RAF-pathway genes (6.2%). Plasma ctDNA remained positive in 42.2% of patients at week 8 and 22.0% at week 24. Week-8 ctDNA persistence was strongly associated with an inferior OS (HR 9.36, 95% CI 3.80–23.03, p < 0.001) after multivariable adjustment. Week-24 positivity also predicted worse OS (HR 3.34, 95% CI 1.13–9.89, p = 0.02). ctDNA status at week 8 or 24 was not significantly associated with PFS. Patients with TP53 or RAF pathway mutations demonstrated higher rates of molecular persistence. Conclusions: In Hispanic patients receiving Osimertinib, ctDNA positivity at 8-24 weeks is able to identify patients with poor survival outcomes. ctDNA monitoring may provide an early, non-invasive biomarker to guide treatment intensification and trial enrollment in EGFR-mutant NSCLC.

PURPOSE Multidisciplinary molecular tumor boards (MTBs) decode complex genomic data into clinical recommendations. Although MTBs are well-established in the oncology practice in developed countries, this strategy needs to be better explored in developing countries. Herein, we describe the possible benefits and limitations of the first MTB established in Colombia. METHODS Demographic, clinical, and genomic information was collected between August 2020 and November 2021. By mid-2020, an MTB strategy was created to discuss clinical cases with one or more genomic alterations identified by next-generation sequencing using an open-access virtual platform. We characterized the patient population as benefiting from the recommended treatment option. We assessed the benefits and access to available targeted therapies that have the potential to change clinical management by making recommendations to treating oncologists on the basis of genomic profiling. However, we did not assess the treatment oncologists' compliance with MTB recommendations because they were not intended to replace clinical judgment/standard of care. RESULTS A total of 146 patients were included in the discussions of the MTB. The median age was 59 years, and 59.6% were women. Genomic results prompting a change in therapeutic decisions were obtained in 53.1% of patients (95% CI, 44.9 to 61.3). The most prevalent malignancy was non–small-cell lung cancer (51%). Other malignancies represented 60%, 50%, and 30% of patients with soft-tissue sarcomas, brain tumors, and breast cancer, respectively. CONCLUSION Using an open-access virtual platform, MTBs were feasible in low- and middle-income countries on the basis of the capability to provide the benefits and access to available targeted therapies that are not standard of care. Furthermore, MTB recommendations were made available to the treating oncologist in different locations across Colombia, providing the option to modify clinical management in most of these patients.

Non-small-cell lung cancer (NSCLC) is a heterogeneous disease, and therapeutic management has advanced to identify various critical oncogenic mutations that promote lung cancer tumorigenesis. Subsequent studies have developed targeted therapies against these oncogenes in the hope of personalized treatment based on the tumor’s molecular genomics. This review presents a comprehensive review of the biology, new therapeutic interventions, and resistance patterns of two well-defined subgroups, tumors with KRAS and MET alterations. We also discuss the status of molecular testing practices for these two key oncogenic drivers, considering the progressive introduction of next-generation sequencing (NGS) and RNA sequencing in regular clinical practice.

Abstract Background: Amplification of EGFR and its active mutant EGFRvIII are common in glioblastoma (GB). While EGFR and EGFRvIII play critical roles in pathogenesis, targeted therapy with EGFR-tyrosine kinase inhibitors (TKIs) or antibodies has shown limited efficacy. To improve the likelihood of effectiveness, we targeted adult patients with recurrent GB enriched for simultaneous EGFR amplification and EGFRvIII mutation, with osimertinib/bevacizumab at doses described for non-small cell lung cancer (NSCLC). Methods: We retrospectively explored whether previously described EGFRvIII mutation in association with EGFR gene amplification could predict response to osimertinib/bevacizumab combination in a subset of 15 patients treated at recurrence. The resistance pattern in a subgroup of subjects is described using a commercial NGS panel in liquid biopsy.Results: There were ten males (66.7%), and the median patient’s age was 56 years (range 38-70 years). After their initial diagnosis, 12 patients underwent partial (26.7%) or total resection (53.3%). Subsequently, all cases received IMRT and concurrent and adjuvant temozolomide (TMZ; the median number of cycles 9, range 6-12). The median follow-up after recurrence was 17.1 months (95% CI 12.3-22.6). All patients received osimertinib/bevacizumab as a second-line intervention with a median progression-free survival (PFS) of 5.1 months (95% CI 2.8-7.3) and overall survival (OS) of 9.0 months (95% CI 3.9-14.0). The PFS6 was 46.7%, and the overall response rate (ORR) was 13.3%. After exposure to the osimertinib/bevacizumab combination, the main secondary alterations were MET amplification, STAT3, IGF1R, PTEN, and PDGFR.Conclusions: While the osimertinib/bevacizumab combination was marginally effective in most GB patients with simultaneous EGFR amplification plus EGFRvIII mutation, a subgroup experienced a long-lasting meaningful benefit. The findings of this brief cohort justify the continuation of the research in a clinical trial. The pattern of resistance after exposure to osimertinib/bevacizumab includes known mechanisms in the regulation of EGFR, findings that contribute to the understanding and targeting in a stepwise rational this pathway.