2023 World Conference on Lung Cancer (Posters)-EP12.01. Therapeutic or Prophylactic Targeting C797S in EGFR Mutant Lung Adenocarcinoma

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This study aimed to evaluate the effectiveness of a combination therapy of osimertinib (an EGFR-TKI) and gefitinib in patients with EGFR-mutated advanced non-small cell lung cancer (NSCLC). The researchers first validated the efficacy of the second-line osimertinib plus gefitinib regimen using patient-derived organoids. They compared the efficacy of this combination therapy with second-line chemotherapy and analyzed the dynamic evolution of tumors using next-generation sequencing techniques. Additionally, they explored the possibility of using osimertinib plus gefitinib as a first-line treatment.<br /><br />The results showed that the second-line osimertinib plus gefitinib regimen effectively killed tumor cells in vitro. However, in real-world settings, the objective response rate (ORR) of the combination therapy was slightly higher than that of chemotherapy, and the disease control rate (DCR) was similar. There was no significant difference in the median progression-free survival (mPFS) between the two treatments. The researchers also found that using osimertinib as a first-line treatment resulted in an ORR of 80% and a DCR of 96%, but the mPFS was only 10.25 months.<br /><br />Based on these findings, the researchers explored the possibility of applying the osimertinib plus gefitinib combination therapy as a first-line treatment. They conducted organoid cultures and drug sensitivity tests using pleural effusions from five patients who had not received any treatment. The results showed that the combination therapy had a significantly reduced IC50 value compared to single-drug osimertinib, and the cell inhibition rate was higher.<br /><br />In conclusion, the study found that the second-line osimertinib plus gefitinib regimen did not show significant advantages in terms of short-term efficacy and progression-free survival compared to second-line chemotherapy. However, the combination therapy of osimertinib and gefitinib as a first-line treatment may be more effective than osimertinib alone. This study highlights the potential of targeted therapies and patient-derived organoids in the treatment of metastatic NSCLC.

Asset Subtitle

Xu-Hui Guan

Meta Tag

Speaker Xu-Hui Guan

Topic Metastatic NSCLC: Targeted Therapy - EGFR/HER2

Keywords

combination therapy

osimertinib

gefitinib

EGFR-mutated NSCLC

patient-derived organoids

chemotherapy

progression-free survival

first-line treatment

pleural effusions

targeted therapies