Clinical Outcome of ALK-Positive Non-Small Cell Lung Cancer (NSCLC) Patients with De Novo EGFR or KRAS Co-Mutations Receiving Tyrosine Kinase Inhibitors (TKIs).

INTRODUCTION: NSCLC with de novo anaplastic lymphoma receptor tyrosine kinase gene (ALK) rearrangements and EGFR or KRAS mutations co-occur very rarely. Outcomes with tyrosine kinase inhibitors (TKIs) in these patients are poorly understood.

METHODS: Outcomes of patients with metastatic NSCLC de novo co-alterations of ALK/EGFR or ALK/KRAS detected by fluorescence in situ hybridization (ALK) and sequencing (EGFR/KRAS) from six Swiss centers were analyzed.

RESULTS: A total of 14 patients with adenocarcinoma were identified. Five patients had ALK/EGFR co-alterations and nine had ALK/KRAS co-alterations. Six of seven patients with ALK/KRAS co-alterations (86%) were primary refractory to crizotinib. One patient has had ongoing disease stabilization for 26 months. Of the patients with ALK/EGFR co-alterations, one immediately progressed after receiving crizotinib for 1.3 months and two had a partial response for 5.7 and 7.3 months, respectively. Three of four patients with ALK/EGFR co-alterations treated with an EGFR TKI achieved one or more responses in different lines of therapy: four patients had a partial response, three with afatinib and one with osimertinib. One patient achieved a complete remission with osimertinib, and one patient was primary refractory to erlotinib. Median PFS during treatment with a first EGFR TKI was 5.8 months (range 3.0-6.9 months).

CONCLUSIONS: De novo concurrent ALK/KRAS co-alterations were associated with resistance to ALK TKI treatment in seven out of eight patients. In patients with ALK/EGFR co-alterations, outcomes with ALK and EGFR TKIs seem inferior to what would be expected in patients with either alteration alone, but further studies are needed to clarify which patients with ALK/EGFR co-alterations may still benefit from the respective TKI.