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NSCLC

Resistance Mechanisms in EGFR-Mutated Lung Cancer Post-Treatment

Publication Title: Genomic Profiling of Epidermal Growth Factor Receptor Mutation-Positive Non-Small Cell Lung Cancer Post-Progression on First-Line Osimertinib: Phase II ORCHARD Study.

Summary

Question
This study examined the molecular changes in tumors from patients with non-small cell lung cancer (NSCLC) who progressed after receiving osimertinib as first-line therapy. The researchers aimed to identify mechanisms of resistance by analyzing tumor samples using next-generation sequencing (NGS), a technology that identifies genetic mutations by analyzing DNA from tissue or blood plasma.
Why it Matters
Osimertinib is the standard treatment for NSCLC patients with mutations in the epidermal growth factor receptor (EGFR) gene, which helps cancer cells grow. However, many patients eventually experience disease progression due to tumor resistance. Understanding the genetic changes responsible for resistance can help clinicians select better second-line treatments, potentially improving outcomes for patients and advancing precision medicine in cancer care.
Methods
The researchers conducted a phase II study called ORCHARD, enrolling patients with EGFR-mutated NSCLC who had progressed after first-line osimertinib therapy. Tumor samples were analyzed using NGS to identify genetic changes linked to resistance. Both tissue biopsies and blood plasma samples were studied, allowing comparisons between the two sources. A total of 400 tissue samples and 191 plasma samples were included.
Key Findings
The researchers found resistance-related genetic alterations in 87% of the analyzed samples, with multiple resistance mechanisms present in 46% of cases. Alterations in the TP53 gene and MDM2/4 genes, which are involved in cell survival and tumor growth, were found in 85% of tumors. Specific changes in the PI3K pathway, SOX2, and MYC genes were associated with tumors that had undergone histological transformation, meaning the tumor changed its cellular structure. Additionally, different patterns of co-occurring EGFR mutations were observed depending on the type of EGFR mutation originally present.
Implications
The findings reveal the diverse and complex nature of resistance to osimertinib, emphasizing the need for treatment strategies that target multiple genetic pathways. By identifying key resistance mechanisms, the study provides insights that could guide the development of personalized combination therapies for NSCLC patients, potentially improving survival and quality of life.
Next Steps
The authors suggest further research into therapies that target the identified resistance pathways, including combination treatments designed to address multiple genetic alterations. Future studies should also explore how histological transformations impact treatment responses and outcomes.
Funding Information
The publication text does not contain specific information about the sources of funding for the research. However, as per the required statement, Yale University also provided funding and support for this research.

Full Citation

Yu H, Tang K, Markovets A, Hartmaier R, Smith P, Cho B, De Langen A, Goldberg S, Goldman J, Le X, Iwama E, Cosaert J, Riess J, Piotrowska Z. Genomic Profiling of Epidermal Growth Factor Receptor Mutation-Positive Non-Small Cell Lung Cancer Post-Progression on First-Line Osimertinib: Phase II ORCHARD Study. Clinical Cancer Research 2026 PMID: 41790029, DOI: 10.1158/1078-0432.ccr-25-4540.

Authors

  • Helena A Yu

    First Author
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  • Zofia Piotrowska

    Last Author
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Yale School of Medicine Authors

Other Authors

  • Kwan Ho Tang;
  • Aleksandra A Markovets;
  • Ryan Hartmaier;
  • Paul E Smith;
  • Byoung Chul Cho;
  • Adrianus Johannes De Langen;
  • Jonathan W Goldman;
  • Xiuning Le;
  • Eiji Iwama;
  • Jan Cosaert;
  • Jonathan W Riess

Research Themes

Concepts