Open Access
CC BY-NC-ND 4.0 · Indian J Med Paediatr Oncol 2019; 40(01): 73-78
DOI: 10.4103/ijmpo.ijmpo_215_18
Original Article

T790M mutation and clinical outcomes with osimertinib in patients with epidermal growth factor receptor-mutant nonsmall cell lung cancer

Authors

  • Ravi Jaiswal

    Department of Medical Oncology, Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, Telangana, India
  • Rakesh Pinninti

    Department of Medical Oncology, Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, Telangana, India
  • MVT Krishna Mohan

    Department of Medical Oncology, Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, Telangana, India
  • A Santa

    Department of Medical Oncology, Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, Telangana, India
  • Pavan Kumar Boyella

    Department of Medical Oncology, Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, Telangana, India
  • Lavanya Nambaru

    Department of Laboratory Medicine, Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, Telangana, India
  • Sudha S Murthy

    Department of Laboratory Medicine, Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, Telangana, India
  • K Veeriah Chowdary

    Department of Radiodiagnosis, Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, Telangana, India
  • Senthil Rajappa

    Department of Medical Oncology, Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, Telangana, India

Financial support and sponsorship Nil.

Abstract

Introduction: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors TKIs) are highly effective in EGFR-mutant advanced lung cancer. The most common resistance mechanism to EGFR-TKI is the development of T790M mutation in Exon 20. Osimertinib, a highly selective EGFR-TKI, has been approved for use in patients who progress on the first-line TKI and harbor the T790M mutation. Objective: The primary objective is to prospectively study the incidence of T790M mutation in patients who progress on the first-line EGFR-TKI. Secondary objectives include clinical characteristics that predict for T790M mutation and outcomes with osimertinib. Materials and Methods: This single-center, prospective observational study included 90 patients who progressed on first-line EGFR TKI. All patients had DNA extracted from tissue re-biopsy or plasma circulating tumor DNA (re-biopsy was not feasible or inadequate). T790M mutation was detected using amplification refractory mutation system-polymerase chain reaction, and patients harboring T790M mutation were started on osimertinib (80 mg once daily) until progression or unacceptable side effects. Results: At progression, T790M mutation was detected in 47/90 patients (52.2%). On binary logistic regression model analysis, variables that were independently predictive of the development of T790M were younger age (odds ratio [OR] 4.3, 95% confidence interval [CI] 1.14–16.6, P = 0.031); nonerlotinib TKI use (OR 8.3, 95% CI 1.24–55.8, P = 0.029); and pure adenocarcinoma histology (OR 6.2, 95% CI 1.60–24.7, P = 0.008). Forty-six patients were started on osimertinib. The overall response rate and median progression-free survival were 65.21% and 12.45 months (standard deviation [SD] 1.03, 95% CI 10.41–14.48), respectively. Osimertinib was well tolerated with most toxicities being Grade 1 and 2 diarrhea and skin rash. Conclusions: In our prospective cohort, half of all patients had a T790M mutation at progression on the first-line EGFR TKI. Tissue biopsy is feasible in the majority of patients. Clinical outcomes with osimertinib were consistent with those reported.



Publication History

Article published online:
08 June 2021

© 2019. Indian Society of Medical and Paediatric Oncology. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).

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