Therapeutic strategies to overcome EGFR mutations as acquired resistance mechanism in ALK-rearranged non-small-cell lung cancer: Case Reports.

Introduction: ALK tyrosine kinase inhibitors (ALK TKIs) have improved prognosis in ALK-rearranged (ALK +) non-small-cell lung cancer (NSCLC). However, drug resistance mechanisms occur inevitably during the course of treatment leading to disease progression. Activation of epidermal growth factor receptor (EGFR) bypass signaling pathway is an uncommon cause of acquired resistance to ALK TKIs. Method: We present two patients with EML4-ALK rearranged NSCLC, developing an acquired EGFR resistance mutation after receiving multiple lines of ALK TKIs. Results: While preclinical models have showed encouraging data, there is a critical need for clinical studies on treatment strategies to overcome this drug resistance. Three real-life therapeutic approaches were used in this report: i) using brigatinib, an inhibitor targeting both ALK and EGFR tyrosine kinases; ii) combining two ALK TKIs together; and iii) delivering doublet platinum chemotherapy. In case 1, time to treatment failure (TTF) was 9.5 months with brigatinib; in case 2, TTF was 10 months with combined TKIs (osimertinib and brigatinib), whereas TTF with chemotherapy was only 2 months. Tolerability profile TKIs combotherapy was acceptable. Conclusion: These case reports underline the therapeutic complexity of EGFR-acquired resistance mutation in ALK+ NSCLC and offers some leads to solve this real-life clinical challenge.

Baseline Hedgehog Pathway Activation and Increase of Plasma Wnt1 Protein Are Associated with Resistance to Immune Checkpoint Inhibitors in Advanced Non-Small-Cell Lung Cancer.

Hedgehog (Hh) and Wingless-type (Wnt) pathways are associated with resistance to immune checkpoint inhibitors (ICIs) in preclinical studies. This study aimed to assess the association between expression and activation levels of Wnt and Sonic Hedgehog (Shh) pathways and resistance to ICIs in advanced NSCLC patients treated with ICI. Hh and Wnt pathways activation was assessed by immunohistochemistry (Gli1 and beta-catenin) on corresponding tumor tissues, and by plasma concentrations of Shh and Wnt (Wnt1, Wnt2 and Wnt3) at ICI introduction and at the first clinical evaluation. Sixty-three patients were included, with 36 patients (57.1%) with available tissue. Response rate was lower in Gli1+ NSCLC (20.0%) compared to Gli1 negative (Gli-) NSCLC (55.6%) (p = 0.015). Rate of primary resistance was 69.8%, vs. 31.2%, respectively (p = 0.04), and median progression-free survival (PFS) was 1.9 months (interquartile range (IQR) 1.2-5.7) vs. 6.1 months (1.6-26.0), respectively (p = 0.08). Median PFS and overall survival were shorter in case of increase of Wnt1 concentration during ICI treatment compared to other patients: 3.9 months vs. 11.2 months (p = 0.008), and 15.3 months vs. not reached (p = 0.003). In conclusion, baseline activation of Hh pathway and increase of Wnt1 concentrations during ICI treatment were associated with poor outcome in NSCLC patients treated with ICIs.

Resistance mechanisms to osimertinib in EGFR-mutated advanced non-small-cell lung cancer: A multicentric retrospective French study.

OBJECTIVES: The understanding of histo-molecular mechanisms associated with resistance to osimertinib is a critical step to define the optimal treatment strategy in advanced EGFR-mutated Non-Small-Cell-Lung-Cancer (NSCLC). MATERIALS AND METHODS: We performed a multicentric retrospective analysis on a cohort of consecutive patients treated with osimertinib for an advanced EGFR-mutated NSCLC and collected histo-molecular data from plasma and tumor samples at the time of progression. Next-generation sequencing (NGS) was performed for all samples. Best Overall Response Rate (ORR), Progression Free Survival (PFS), Overall Survival (OS) and data on treatment post-progression efficacy were also collected. RESULTS: Two-hundred and twenty-six patients were included from 9 Academic French Hospitals between April 2015-October 2018. Osimertinib was given in second-line or more in 219 patients (97%). Best ORR was 52% and best central nervous system ORR was 56%. Median PFS and OS were 9.5 months (IQR 4.0-17.2) and 24 months (IQR 12.4-NR) respectively. At the time of analysis, 150 patients (66%) had tumor progression. Among them, 73 contributive samples (56 tumor biopsies) were available. The most frequent molecular alterations were C797S mutation (n = 9 (13%)) and MET amplification (n = 8 (11%)). Histologic transformation occurred in 5 patients (9% of tumor biopsies). In T790M + NSCLC, loss of T790 M occurred in 68% of cases. Median PFS and OS with treatment beyond progression were 6.0 months (IQR 2.0-10.4) and 15.1 months (IQR 6.7-NR) respectively and longer in case of osimertinib continuation beyond progression. CONCLUSION: We confirmed the efficacy of osimertinib in patients with advanced EGFR mutation positive NSCLC. At progression, the most frequent molecular alterations were MET amplification and C797S mutation.