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Published on: June 26, 2019
Higher osimertinib introduction rate achieved by multiple repeated rebiopsy after acquired resistance to first/second
Taira Ninomaru1, Akito Hata1, Chiyuki Kokan1
1Division of Thoracic Oncology, Kobe Minimally Invasive Cancer Center, Kobe, Japan.
Background:
Indication for treatment with osimertinib after first/second generation (1/2G) epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) resistance depends on T790M mutation detected by rebiopsy. The aim of our study was to analyze the data on clinical practice at our hospital where histological rebiopsy is actively carried out multiple times.
Methods:
We retrospectively reviewed our electronic medical records of EGFR-mutant non-small cell lung cancer (NSCLC) patients to examine clinical rebiopsy situation, T790M detection rate, osimertinib introduction rate and associated outcomes.
Results:
Among 95 patients with EGFR-mutant NSCLC, 72 patients received 1/2G EGFR-TKIs. Of 60 with progressive disease on 1/2G EGFR-TKIs, 50 (83%) underwent rebiopsy. T790M was detected in 40 (80%) of 50, resulting in a 79% osimertinib introduction rate, as one patient refused osimertinib. T790M was detected by first rebiopsy in 18 (36%) of 50 patients, and by second or subsequent rebiopsy in 22 (44%). Median time to treatment failure of T790M-positive patients at first rebiopsy was 22.6 (95% confidence interval [CI]: 10.2-32.8) months, and those at multiple repeated rebiopsy was 20.9 (95% CI: 8.6-not reached) months (p = 0.64). Median overall survival (OS) in osimertinib introduced group was 92.5 (95% CI: 62.9-not reached), while in nonosimertinib median OS was 39.0 months (95% CI: 22.2-not reached) (p = 0.04).
Conclusions:
T790M detection rate was increased by multiple repeated rebiopsy, achieving a higher osimertinib introduction rate. This higher introduction rate could contribute to better prognosis of EGFR-mutant NSCLC patients.
Insights
Multiple rebiopsies increase T790M detection rates in non-small cell lung cancer (NSCLC) patients resistant to EGFR-TKIs. This leads to higher osimertinib use and improved overall survival for NSCLC patients.
Area of Science:
- Oncology
- Medical Diagnostics
- Pharmacology
Background:
- Treatment with osimertinib for EGFR-mutant NSCLC is indicated after resistance to first/second-generation EGFR-TKIs.
- This indication relies on detecting the T790M mutation via rebiopsy.
- Clinical practice often involves multiple, repeated histological rebiopsies.
Purpose of the Study:
- To analyze the clinical practice of repeated rebiopsies in EGFR-mutant NSCLC patients.
- To evaluate the T790M mutation detection rate and osimertinib introduction rate.
- To assess the outcomes associated with rebiopsy strategies and osimertinib treatment.
Main Methods:
- Retrospective review of electronic medical records for EGFR-mutant NSCLC patients.
- Examination of rebiopsy frequency, T790M detection rates, and osimertinib initiation.
- Analysis of clinical outcomes, including time to treatment failure and overall survival.
Main Results:
- Of 60 patients with progressive disease on 1/2G EGFR-TKIs, 50 (83%) underwent rebiopsy.
- T790M mutation was detected in 40 (80%) of rebiopsied patients, leading to a 79% osimertinib introduction rate.
- Multiple rebiopsies increased T790M detection (44% vs. 36% in first rebiopsy). Median OS was significantly higher in the osimertinib group (92.5 months vs. 39.0 months).
Conclusions:
- Repeated rebiopsies enhance T790M mutation detection rates in EGFR-mutant NSCLC.
- Increased T790M detection facilitates higher osimertinib introduction rates.
- This strategy may contribute to improved prognosis for EGFR-mutant NSCLC patients.
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