By Anthony Magliocco MD
TAGRISSO delivered unprecedented median progression-free survival of 18.9 months versus 10.2 months for EGFR-TKIs (erlotinib or gefitinib) in 1st-line EGFRm NSCLC
the US Food and Drug Administration (FDA) has approved TAGRISSO® (osimertinib) for the 1st-line treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors have epidermal growth factor receptor (EGFR) mutations (exon 19 deletions or exon 21 L858R mutations), as detected by an FDA-approved test. The approval is based on results from the Phase III FLAURA trial, which were presented at the European Society of Medical Oncology 2017 Congress and published in the New England Journal of Medicine.
The results of the phase III FLAURA trial were impressive with dramatic improvements to progression free survival.
The FLAURA trial compared TAGRISSO to current 1st-line EGFR tyrosine kinase inhibitors (TKIs), erlotinib or gefitinib, in previously untreated patients with locally advanced or metastatic EGFR-mutated (EGFRm) NSCLC. TAGRISSO met the primary endpoint of progression-free survival. PFS results with TAGRISSO were consistent across all pre-specified patient subgroups, including in patients with or without central nervous system (CNS) metastases. Overall survival data were not mature at the time of the final PFS analysis.
Osimertinib was previously approved for use as second line therapy in patients who had progressed on a TKI treatment or for those whose tumors developed a T790M mutation confering resistance to the first generation TKI therapies.
Osimerinibs mechanism of action is thought to be irreversible binding to the EGFR receptor. Perhaps this explains the improvement in PFS compared to other TKIs. These findings are potentially practice changing.
Despite these impressive improvements in PFS almost all patients eventually fail targeted therapies with TKI agents. Consequently more work is needed to understand the biological mechanisms of resistance and progression in lung cancer patients to enable more effective therapies to be developed.