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Poster Display session

23P - Impact of PDL1 expression on outcomes of patients with EGFR mutant NSCLC treated with EGFR TKIs: First results of the POET study


31 Mar 2023


Poster Display session


Lorenzo Belluomini


Journal of Thoracic Oncology (2023) 18 (4S): S35-S88.


L. Belluomini1, M.G. Ferrara2, M. Sposito3, A. Vitale2, J. Insolda3, E. Vita2, D. Giannarelli4, A. Stefani2, M. Milella3, E. Bria2, S. Pilotto3

Author affiliations

  • 1 Verona/IT
  • 2 Fondazione Policlinico Universitario Agostino Gemelli IRCCS - Università Cattolica del Sacro Cuore, Rome/IT
  • 3 AOU Integrata di Verona - Ospedale Borgo Roma, Verona/IT
  • 4 Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome/IT


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Abstract 23P


In EGFR mutant NSCLC, acquired resistance to EGFR tyrosine kinase inhibitors (TKIs) inevitably occurs. To date, inconclusive results have been published or presented regarding the predictive/prognostic role of PDL1 expression in EGFR mutant NSCLC treated with TKIs.


A retrospective analysis of patients treated with first (Erlotinib/Gefitinib), second (Afatinib) and third generation (Osimertinib) EGFR-TKIs was conducted. The main objective was to evaluate the potential correlation between levels of PDL1 expression and anti-EGFR treatment efficacy in terms of overall survival (OS) and progression-free-survival (PFS).


Data from 171 patients (median age 69.0 years) who received EGFR TKIs were gathered. The most common EGFR alteration was ex19del (52.6%). 26 patients (15.2%) showed high PDL1 expression (≥50%). 105 patients (61.4%) were treated with Osimertinib, while 22.2%, 12.3% and 4.1% were treated with Gefitinib, Afatinib and Erlotinib, respectively. In the overall population, the objective response rate was 61%, mPFS 19.1 months (15.1–23.1) and 2-year OS 61.5%. Results of multivariate analysis are reported in the table. Patients with PDL1 <50% showed mPFS of 15.4 (9.3–21.5) versus 23.6 months (18.6–28.6) with first/second and third generation TKIs, respectively (p = 0.018). Patients with PDL1 ≥50% showed mPFS of 8.0 months (3.1–12.8) versus 10.2 months (0–30.5) with first/second and third generation TKIs, respectively (p = 0.03). In the high PDL1 subgroup, a significant difference in OS was observed (mOS 24.9 versus 31.3 months with first/second versus third generation TKIs; p = 0.030). No statistically significant differences were reported when the analysis was limited to the first-line setting.

Table: 23P
Univariate HR (95% CI)Multivariate HR (95% CI)
ECOG PSP < 0.0001P = 0.002
11.33 (0.80–2.21)1.60 (0.95–2.72)
2–35.09 (2.70–9.60)3.73 (1.78–7.82)
PDL1P = 0.03P = 0.073
>=50%1.87 (1.06–3.29)1.71 (0.95–3.08)
Mutationp = 0.11
Esone 191.00
Esone211.24 (0.77–2.00)
Number of met sitesP = 0.40
21.69 (0.71–4.03)
>=31.72 (0.78–3.79)
SurgeryP = 0.03P = 0.095
Yes0.46 (0.23–0.93)0.54 (0.26–1.12)
TKIsP = 0.006P = 0.001
Afatinib0.62 (0.31–1.26)0.48 (0.22–1.06)
Osimertinib0.45 (0.27–0.73)0.36 (0.21–0.61)
First-lineP < 0.0001P = 0.08
Yes0.14 (0.06–0.35)0.39 (0.13–1.12)


Our study supports the survival benefit of Osimertinib compared to first/second generation TKIs, regardless of PDL1 expression. A larger data collection is ongoing and updated results will be presented at the Conference.

Legal entity responsible for the study

The authors.


Has not received any funding.


E. Bria: Financial Interests, Personal, Advisory Board: AstraZeneca, Roche, BMS, MSD, Eli Lilly, Amgen; Financial Interests, Institutional, Research Grant: AstraZeneca, Roche. S. Pilotto: Financial Interests, Personal, Invited Speaker: Bristol Myers Squibb, AstraZeneca, Merck & Co., Roche, Amgen, Novartis; Financial Interests, Personal, Advisory Board: Merck & Co., Amgen, AstraZeneca, Novartis; Financial Interests, Personal, Expert Testimony: Takeda; Financial Interests, Personal, Research Grant: Bristol Myers Squibb, AstraZeneca; Non-Financial Interests, Personal, Principal Investigator: AstraZeneca, Roche. All other authors have declared no conflicts of interest.

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