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N. Gibson
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P3.01 - Advanced NSCLC (ID 621)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.01-043 - Impact of ErbB Mutations on Clinical Outcomes in Afatinib- or Erlotinib-Treated Patients with SCC of the Lung (ID 9457)
09:30 - 09:30 | Author(s): N. Gibson
- Abstract
Background:
In LUX-Lung 8 (LL8), second-line afatinib (an irreversible ErbB family blocker) significantly improved OS (median 7.9 versus 6.8 months; HR [95% CI]: 0.81 [0.69‒0.95]; p=0.0077), and PFS (2.6 versus 1.9 months; 0.81 [0.69‒0.96]; p=0.0103) versus erlotinib in lung SCC (N=795). Comprehensive genetic analysis in LL8 patients assessed whether afatinib efficacy varied according to genetic aberrations in cancer-related genes, including ErbB family mutations.
Method:
Tumor genetic analysis (TGA) was performed using Foundation Medicine FoundationOne™ next-generation sequencing (NGS). The cohort was enriched for patients with PFS >2 months, reflecting a range of responsiveness to EGFR-TKIs. EGFR expression was assessed by immunohistochemistry (IHC) in a largely separate cohort. Cox regression analysis correlated PFS/OS with genetic mutations (individual/grouped) and EGFR expression.
Result:
Of 440 patients selected for TGA (PFS >2 months: n=320; ≤2 months: n=120), samples from 245 were eligible (afatinib: n=132; erlotinib: n=113). In the selected TGA population, PFS/OS outcomes were improved in the afatinib versus erlotinib arm. Baseline characteristics were similar in TGA and IHC cohorts and LL8 overall. In the TGA subset, 53 patients (21.6%) had ≥1 ErbB family mutation (EGFR: 6.5%; HER2: 4.9%; HER3: 6.1%; HER4: 5.7%). Beyond the benefit seen for afatinib in the overall population, in afatinib-treated patients, PFS/OS were longer when ErbB mutations were present (PFS: 4.9 versus 3.0 months; OS: 10.6 versus 8.1 months). Conversely, survival outcomes in erlotinib-treated patients were similar with/without ErbB mutations. Presence of HER2 mutations predicted favorable PFS/OS with afatinib versus erlotinib. The Table shows outcomes in patients with/without ErbB family mutations, and by EGFR expression levels (afatinib: n=157; erlotinib: n=188).
Conclusion:
These data are provocative and suggest that NGS may enable identification of lung SCC patients who would derive additional clinical benefit from afatinib. Differential outcomes with respect to ErbB mutations for afatinib and erlotinib are hypothesized to reflect afatinib’s broader mechanism of action.Subgroup n Afatinib vs erlotinib PFS OS HR (95% CI) p~interaction~ HR (95% CI) p~interaction~ ErbB mutation-positive ErbB mutation-negative 53 192 0.56 (0.29–1.08) 0.70 (0.50–0.97) 0.718 0.62 (0.35‒1.12) 0.76 (0.56‒1.03) 0.683 EGFR mutation-positive EGFR mutation-negative 16 229 0.64 (0.17–2.44) 0.67 (0.50–0.91) 0.981 1.01 (0.32–3.16) 0.72 (0.54–0.95) 0.529 HER2 mutation-positive HER2 mutation-negative 12 233 0.06 (0.01–0.59) 0.72 (0.54–0.97) 0.006 0.06 (0.01–0.57) 0.76 (0.58–1.00) 0.004 HER3 mutation-positive HER3 mutation-negative 15 230 0.52 (0.16–1.72) 0.69 (0.51–0.94) 0.692 0.84 (0.27–2.59) 0.73 (0.56–0.97) 0.998 HER4 mutation-positive HER4 mutation-negative 14 231 0.21 (0.02–1.94) 0.67 (0.50–0.91) 0.909 0.22 (0.05–1.04) 0.75 (0.56–0.99) 0.272 EGFR IHC positive EGFR IHC negative 292 53 0.74 (0.56–0.97) 0.76 (0.41–1.40) 0.985 0.82 (0.63–1.06) 0.75 (0.41–1.40) 0.882 EGFR amplification present EGFR amplification absent 17 228 0.72 (0.18–2.90) 0.68 (0.50–0.92) 0.994 0.50 (0.15–1.65) 0.76 (0.58–1.00) 0.413 HER2 amplification present HER2 amplification absent 9 236 0.94 (0.20–4.38) 0.68 (0.50–0.91) 0.861 1.10 (0.27–4.48) 0.72 (0.54–0.94) 0.388
