Real-world Experience With Combination Chemotherapy and Osimertinib in Poor Prognostic Group of Metastatic EGFR-mutated Lung Adenocarcinoma

Inclusion Criteria

• •1. Adults above 18 years old, both male and female;
• •2. Pathologically confirmed lung adenocarcinoma with stage IIIB/C or IV disease (TNM staging version 8);
• •3. Confirmed EGFR common sensitizing mutations (exon 21 L858R or exon 19 del) by locally approved molecular testing methods (allele-specific PCR or NGS) based on tumour tissues or plasma ctDNA;
• •4. Clinically decided for first-line systemic treatment with osimertinib;
• •5. Detectable pre-treatment plasma EGFR mutations (by Cobas EGFR Mutation Test v2) and failed clearance 3 weeks (+/- 5 days) after osimertinib treatment;
• •6. At least one measurable target lesion by RECIST v1.1 criteria;
• •7. Performance state (ECOG) ≤ 1 and life expectancy ≥ 12 weeks;
• •8. Females in reproductive age with negative pregnancy test and highly effective means of contraception during and ≥ 4 months after intervention period;
• •9. Males should agree to have highly effective means of contraception during and ≥ 4 months after intervention period; and
• •10. Written informed consent obtained.