Dramatic response to osimertinib combined with crizotinib in EGFR T790 M mutation only in blood and Met amplification only in tumor tissue expressive non-small cell lung cancer: A case report.

Rationale: Besides the T790 M mutation, it may coexist with bypass pathway activation in real clinical cases for patients with EGFR mutations who resisted to the first- and second-generation tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC). There are limited clinical trial data describing the efficacy of osimertinib combined with MET inhibition in EGFR T790M-mutant NSCLC patients with Met amplification.

Patient Concerns: A non-smoking 53-year-old male patient with lung adenocarcinoma underwent gefitinib, afatinib, and osimertinib combined with crizotinib treatment and developed different EGFR resistance mutations.

Diagnoses: The patient was diagnosed with lung adenocarcinoma (stage cT4N2M0, IIIB). After resistance to the therapy targeting EGFR exon 21 L858R point mutation, T790 M mutation was detected in liquid biopsy and Met amplification was detected via tissue biopsy by next-generation sequencing (NGS).

Interventions: The patient received systemic treatments, including chemotherapy, gefitinib, afatinib, and osimertinib combined with crizotinib.

Outcomes: The patient died of multisystem organ failure and had an overall survival of 24 months.

Lessons: Although osimertinib combined with crizotinib therapy showed dramatic tumor shrinkage in both the primary tumor and bone metastasis to an EGFR T790M-mutant NSCLC patient with MET amplification, the progression-free survival (PFS) was only two months.