Generations of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors: Perils and Progress
Emily H Castellanos1, Leora Horn2
1Vanderbilt Ingram Cancer Center, 2220 Pierce Avenue, 777 Preston Research Building, Nashville, TN, 37232, USA.
Opinion Statement:
Epidermal growth factor receptor (EGFR) mutations have been detected in approximately 10 % of North American patients diagnosed with non-small cell lung cancer (NSCLC). Approximately 90 % of these mutations are exon 19 deletions or exon 21 L858R point mutations. First- and second-generation EGFR tyrosine kinase inhibitors (TKIs) are approved as first-line therapy based on clinical trials demonstrating superior response rates, progression free survival (PFS), and overall survival (OS) compared to chemotherapy in patients with EGFR mutation-positive NSCLC treated with an EGFR TKI prior to chemotherapy. However, the majority of patients treated with an EGFR TKI develop resistance to therapy within about 12 months, approximately 50 % of patients due to a second site mutation, the T790M mutation occurring within exon 20. At the time of progression, the EGFR TKI is most commonly discontinued and a different systemic therapy is initiated. However, oncogene addiction persists and recent exciting data with third-generation EGFR TKIs suggests that acquired resistance may be surmountable. The newest EGFR TKIs have shown activity against EGFR-mutant NSCLC after progression on first-generation TKIs, including those with T90M, while sparing wild-type EGFR and hence appear to be both well tolerated and efficacious. At this time, it appears that third-generation EGFR TKIs are effective following first-generation therapy, and determining the most appropriate sequence to maximize overall survival is a matter of ongoing investigation. As the arsenal of active agents in EGFR mutant NSCLC grows, future research into potential combinations, optimal timing, and resistance mechanisms of these new treatments, as well as their possible role in the adjuvant, post-chemoradiation, and neoadjuvant settings holds great promise for this group of patients.
Insights
Third-generation EGFR TKIs show promise in treating non-small cell lung cancer (NSCLC) resistant to earlier therapies. These new treatments are effective after first-generation EGFR tyrosine kinase inhibitors (TKIs), offering hope for improved patient outcomes.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Epidermal growth factor receptor (EGFR) mutations are common in non-small cell lung cancer (NSCLC), with exon 19 deletions and exon 21 L858R mutations being most prevalent.
- First- and second-generation EGFR tyrosine kinase inhibitors (TKIs) are effective first-line treatments for EGFR-mutant NSCLC, but resistance typically develops within a year.
- The T790M mutation is a common cause of acquired resistance to EGFR TKIs in NSCLC.
Purpose of the Study:
- To evaluate the efficacy and tolerability of third-generation EGFR TKIs in NSCLC patients who have progressed on first-generation TKIs.
- To explore the potential of third-generation EGFR TKIs in overcoming acquired resistance, including T790M mutations.
- To discuss the evolving treatment landscape for EGFR-mutant NSCLC and future research directions.
Main Methods:
- Review of recent clinical trial data and scientific literature on EGFR TKIs in NSCLC.
- Analysis of response rates, progression-free survival (PFS), and overall survival (OS) in patients treated with third-generation TKIs.
- Assessment of safety profiles and tolerability of newer EGFR TKIs, particularly their sparing of wild-type EGFR.
Main Results:
- Third-generation EGFR TKIs demonstrate significant activity against EGFR-mutant NSCLC, even after progression on earlier TKIs.
- These newer agents show efficacy in patients with T790M resistance mutations.
- Third-generation TKIs appear well-tolerated due to their selectivity for mutant EGFR over wild-type EGFR.
Conclusions:
- Third-generation EGFR TKIs represent a promising therapeutic option for NSCLC patients with acquired resistance to first-generation TKIs.
- Ongoing research is crucial to determine optimal sequencing strategies and explore combinations for maximizing survival.
- Future investigations should focus on resistance mechanisms, optimal timing, and the role of these agents in various treatment settings (adjuvant, neoadjuvant, post-chemoradiation).
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