Background: Despite the development of predictive biomarkers to shape treatment paradigms and outcomes, 10-20% of de novo EGFR TKI resistance advanced non-small cell lung cancer (NSCLC) in the presence of EGFR mutation remains the issue of concern. Methods: We explored clinical factors in 332 advanced NSCLC who received EGFR TKI and molecular characteristics through 65 whole exome sequencing of various EGFR TKI responses including; de novo (progression within 3 months), intermediate response (IRs) and long-term response (LTRs) (durability > 2 year). Results: Uncommon EGFR mutation subtype was a significant variable in de novo resistance vs. IRs and LTRs with odd ratios of 6.83 ([95% CI 2.36 – 19.80], p-value < 0.001) and 16.84 ([95%CI 1.66 – 171.45, p-value 0.02), respectively. The remaining sensitizing EGFR mutation subtype (exon 19 del and L858R) accounted for 75% of de novo resistance. Genomic landscape analysis was conducted, focusing in 10 frequent oncogenic signaling pathways with functional contributions; cell cycle, Hippo, Myc, Notch, Nrf2, PI-3-Kinase/Akt, RTK-RAS, TGF-β, p53 and β-catenin/Wnt signaling. Cell cycle pathway was the only significant alteration pathway among groups with the FDR p-value of 6×10^-4. We found only significant q-values of < 0.05 in 7 gene alterations; CDK6, CCNE1, CDK4, CCND3, MET, FGFR4 and HRAS which enrich in de novo resistance [range 36-73%] compared to IRs/LTRs [range 4-22%]. Amplification of CDK4/6 was significant in de novo resistance, contrary to IRs and LTRs (91%, 27.9% and 0%, respectively). The presence of co-occurrence CDK4/6 amplification correlated with poor disease outcome with HR of progression-free survival of 3.63 [95% CI 1.80-7.31, p-value < 0.001]. Conclusions: The presence of CDK4/6 amplification in pretreatment specimen serve as a predictive biomarker for de novo resistance in sensitizing EGFR mutation.