Two expert analyses appearing in the same issue of the Journal of Thoracic Oncology arrive at opposite conclusions regarding the value for metastatic non–small cell lung cancer (mNSCLC) of combining first-generation endothelial growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) with either chemotherapy or vascular EGF (VEGF) monoclonal antibodies. One affirms single-agent EGFR TKI treatment, such as with osimertinib, as the current standard of care for first-line advanced metastatic EGFR-positive mNSCLC, and the other affirms clear benefits for first-generation EGFR TKIs combined with either chemotherapy or VEGF monoclonal antibodies.
In the analysis supporting combination therapy for mNSCLC, Sara Moore, MD, and Paul Wheatley-Price MD, wrote that while targeted therapy with EGFR TKIs is highly effective initially, resistance inevitably develops.
Recent data, they stated, have demonstrated that combination strategies can delay development of resistance and improve outcomes for mNSCLC populations. Combining first-generation EGFR TKIs with either chemotherapy or VEGF monoclonal antibodies has led to consistent improvement in progression-free survival (PFS) and overall survival (OS) in some cases. In the NEJ009 trial, the combination of chemotherapy (carboplatin and pemetrexed, with pemetrexed maintenance) plus gefitinib vs gefitinib alone improved response rate (84% vs 67%; P < 0.001), PFS (median, 20.9 months vs 11.2 months; P < .001), and OS (median, 50.9 months vs 38.8 months; P = .021). An increase in adverse events in the chemotherapy arm led to a decrease in quality of life.
Another clinical trial (by Noronha and colleagues) conducted in India of the same combination found benefit for combination therapy in response rate (75% vs 63%), PFS (median, 16 months vs 8 months), and OS (not reached vs 17 months). Grade 3 or higher adverse event rates were higher with the combination (51% vs 25%) with quality of life was not yet reported.
While both trials have been criticized owing to a lack of standard T790M resistance testing and low use of osimertinib in subsequent lines of therapy, Moore and Wheatley-Price pointed out: “Even with the use of first-line osimertinib monotherapy, patients may still be exposed to chemotherapy with later lines of treatment. Therefore, combination therapy does not expose patients to new toxicity, it simply changes when they will be exposed to that toxicity during their treatment course.”
The importance of using combination therapy in the first-line setting, they stated, is underscored by the consistent drop-off in patients who receive second-line combination therapy. In the phase 3 FLAURA trial of first-line osimertinib monotherapy, of the patients who discontinued osimertinib, the most common reason for not receiving subsequent therapy was death (60% went on to receive further systemic therapy). This highlights the need to use the most effective treatments up front, Moore and Wheatley-Price wrote.
The four large trials of VEGF-targeted therapy with either monoclonal antibodies or TKIs added to first-generation EGFR TKIs have consistently shown improved PFS. Increased toxicities led to discontinuation of VEGF-targeted therapy in 20%-30%.
In the RELAY trial, however, despite more toxicities, quality of life was not diminished. In general, the authors concluded that long-term detriments to quality of life have not been demonstrated. Ongoing studies of osimertinib in combination with VEGF inhibition include a phase 1/2 trial with bevacizumab in previously untreated patients showing an 80% response rate (median PFS, 18.4 months) with no unexpected toxicity.
Chemotherapy-based treatment for mNSCLC with third-generation EGFR TKIs, in appropriately selected patients, the authors concluded, “can offer an additional standard-of-care option as first-line treatment of EGFR-mutant lung cancer.” Read more.
Here’s another article, Chemoimmunotherapy for EGFR-Mutant NSCLC: Still No Clear Answer on this topic.