Background
Prespecified CNS subgroup analysis of FLAURA, a phase III double-blind RCT, N=556 untreated EGFR-mutant (exon 19 del/L858R) advanced NSCLC. First-line osimertinib (3rd-gen CNS-penetrant EGFR TKI) vs 1st-gen EGFR TKI (gefitinib/erlotinib). CNS subgroup with baseline brain mets n=200 (116 osimertinib, 84 comparator).
Interventions and follow up
Arm A: Osimertinib 80 mg PO QD
Arm B: Gefitinib 250 mg or erlotinib 150 mg PO QD
Primary endpoint: CNS PFS; CNS ORR (measurable lesions); CNS duration of response
mFollow up: 18.0 months (primary analysis)
Arm B: Gefitinib 250 mg or erlotinib 150 mg PO QD
Primary endpoint: CNS PFS; CNS ORR (measurable lesions); CNS duration of response
mFollow up: 18.0 months (primary analysis)
Results
CNS ORR (measurable lesions, n=46): 91% vs 68%, P=.014
CNS PFS (baseline BM): HR 0.48, 95% CI 0.26-0.86, P=.014, favoring osimertinib
CNS PFS (no baseline BM): HR 0.48, 95% CI 0.27-0.84, P=.009
FLAURA mPFS: 18.9 vs 10.2 months, HR 0.46, P<.0001
FLAURA OS: mOS 38.6 vs 31.8 months, HR 0.80, P=.046
CNS PFS (baseline BM): HR 0.48, 95% CI 0.26-0.86, P=.014, favoring osimertinib
CNS PFS (no baseline BM): HR 0.48, 95% CI 0.27-0.84, P=.009
FLAURA mPFS: 18.9 vs 10.2 months, HR 0.46, P<.0001
FLAURA OS: mOS 38.6 vs 31.8 months, HR 0.80, P=.046
Adverse events
Grade ≥3 AEs: 34% vs 45%
Diarrhea Grade ≥3: 1% vs 4%
Rash/acneiform Grade ≥3: 1% vs 7%
QTc prolongation Grade ≥3: 1% vs <1%
Interstitial lung disease: 3% vs 2%
Cardiomyopathy/cardiac failure (osimertinib): 3% all grades, <1% Grade ≥3
Diarrhea Grade ≥3: 1% vs 4%
Rash/acneiform Grade ≥3: 1% vs 7%
QTc prolongation Grade ≥3: 1% vs <1%
Interstitial lung disease: 3% vs 2%
Cardiomyopathy/cardiac failure (osimertinib): 3% all grades, <1% Grade ≥3
Conclusions
Osimertinib demonstrated superior CNS activity over 1st-gen EGFR TKI in EGFR-mutant NSCLC (91% vs 68% intracranial ORR; 52% reduction in CNS progression risk), establishing it as the preferred first-line EGFR inhibitor in patients with or without brain metastases.
Key Limitations
Prespecified subgroup, underpowered for CNS-specific hypothesis testing in BM subgroup (n=200); BM by local MRI; CNS ORR denominator small (n=46), limiting precision; comparator was 1st-gen TKI, not 2nd-gen afatinib/dacomitinib; FLAURA OS benefit (HR 0.80) modest with ~30% crossover to osimertinib at T790M progression.
Clinical Context
FLAURA established osimertinib as preferred first-line therapy for EGFR-mutant (exon 19 del/L858R) NSCLC, particularly with brain metastases; ESMO endorses it as a standard 1L option. High intracranial ORR and CNS PFS benefit justify deferring brain RT in most asymptomatic EGFR+ NSCLC brain mets. LAURA extends osimertinib to unresectable stage III post-CRT; FLAURA2 (osimertinib + chemotherapy) further improved PFS (HR 0.62). For acquired resistance, MARIPOSA-2 (amivantamab + carboplatin + pemetrexed) improved PFS post-osimertinib. For exon 20 insertions, amivantamab is needed (osimertinib inactive).