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Eng-Huat Tan
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P1.01 - Advanced NSCLC (Not CME Accredited Session) (ID 933)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 2
- Moderators:
- Coordinates: 9/24/2018, 16:45 - 18:00, Exhibit Hall
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P1.01-28 - Impact of Afatinib Dosing on Safety and Efficacy Real-World in Patients with EGFR Mutation-Positive Advanced NSCLC (ID 13276)
16:45 - 18:00 | Author(s): Eng-Huat Tan
- Abstract
Background
Tolerability-guided dose adjustment of afatinib reduced incidence and severity of adverse drug reactions (ADRs) without affecting efficacy in the LUX-Lung (LL) studies in patients with EGFR mutation-positive (EGFRm+) NSCLC. We evaluated the impact of modifying the recommended starting dose of afatinib (40mg) on efficacy and safety in a real-world setting.
a9ded1e5ce5d75814730bb4caaf49419 Method
This non-interventional, observational, multi-country/site study used medical records of TKI-naïve patients with EGFRm+ (Del19/L858R) NSCLC treated with first-line afatinib. Primary outcomes were % patients with ADRs by severity, time on treatment (TT), and time to progression (TTP), relative to LL3. Secondary outcomes were % of patients with/reasons for modified starting dose.
4c3880bb027f159e801041b1021e88e8 Result
228 patients from 13 countries were included. Baseline characteristics were generally similar to LL3, but with more Del19 patients (78% vs 49%) and fewer Asian patients (44% vs 72%); 12% had ECOG PS 2–3. 31% of patients received an afatinib starting dose of <40 mg; 20% of patients starting with <40 mg increased their dose during the study. 67% of 40 mg starters underwent dose reductions, with 86% of those occurring in the first 6 months. Dose reductions were more frequent in females, Eastern Asian patients, and those with lower body weight. The main reason for dose modification was ADRs. In <40 mg starters, overall ADR incidence was similar to that in ≥40 mg starters, with fewer G3 (17% vs 25%) and no G4 ADRs. There were no new safety signals, and fewer ≥G3 ADRs and serious adverse events (SAEs) than in LL3 (28% vs 49% and 5% vs 14%, respectively). >60% of patients received medications to treat diarrhea and manage skin AEs. Median TT and TTP were 18.7 months and 20.8 months, respectively, and were not impacted by reduced starting dose or dose modification (19.4/17.7/19.5 and 25.9/20.0/29.0 months for patients who started on ≤30 mg/reduced to <40 mg/remained on ≥40 mg, respectively). The efficacy of afatinib was demonstrated across all patient subgroups analysed (ECOG PS 0/1 vs 2/3, age <75 yrs vs ≥75 yrs, EGFR mutational status); TT and TTP were significantly longer in patients with ECOG PS0/1 versus PS2/3.
8eea62084ca7e541d918e823422bd82e Conclusion
As in pivotal trials, dose adjustments with afatinib in real-world practice reduced the frequency and intensity of ADRs without impacting efficacy. RealGido demonstrated long TT/TTP regardless of afatinib dose adjustment or reduced starting dose, and an acceptable safety profile. The results highlight the benefit of tailoring afatinib dose based on individual patient characteristics and ADRs to optimize outcomes.
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P1.01-98 - A Phase IIIb Trial of Afatinib in EGFRm+ NSCLC: Analyses of Outcomes in Patients with Brain Metastases or Dose Reductions (ID 12906)
16:45 - 18:00 | Author(s): Eng-Huat Tan
- Abstract
Background
We previously reported interim results of a large (n=479) open-label, single-arm Phase IIIb study of afatinib in EGFR TKI-naïve patients with EGFRm+ NSCLC, in a setting similar to ‘real-world’ practice (Wu et al, WCLC, 2017). In this broad population of Asian patients, the tolerability profile of afatinib was predictable and manageable. Adverse events (AEs) were consistent with the LUX-Lung 3, 6 and 7 trials; 3.8% of patients discontinued due to drug-related AEs. Progression-free survival (PFS) and time to symptomatic progression (TTSP) was encouraging, in patients with both common and uncommon EGFR mutations. TTSP data suggested effective treatment beyond progression. Here, we assess the impact of baseline brain metastases and use of dose reductions on efficacy outcomes.
a9ded1e5ce5d75814730bb4caaf49419 Method
Patients with locally advanced/metastatic EGFRm+ NSCLC were recruited in China, Hong Kong, India, Singapore and Taiwan. Afatinib 40mg/day was given until disease progression (investigator-assessed) or lack of tolerability. Treatment-related AEs could be managed by protocol-specified tolerability-guided dose adjustment.
4c3880bb027f159e801041b1021e88e8 Result
At data cut-off (13 Feb 2017), patient characteristics were as follows: median age, 59.0 years; female, 52.4%; EGFR mutations: Del19+/-L858R+/-uncommon, 86.0%; uncommon only, 14.0%; ECOG PS0, 19.8%; PS1, 78.1%. Prior chemotherapy lines: 0, 59.7%; 1, 30.1%; ≥2, 10.2%.
Overall, dose reductions from 40mg/day to 30mg/day occurred in 119 patients (25%). Incidences of the most frequently reported AEs before and after dose reduction were (any grade): diarrhea, 96/51%; rash/acne, 69/58%; stomatitis, 65/42%; (≥grade 3) diarrhea, 27/4%; rash/acne, 24/11%; stomatitis, 11/5%. A total of 96 patients had a dose reduction during the first six months; median PFS in this subgroup was 14.1 months (95% CI: 10.0–19.3) versus 11.33 (10.7–13.6) months in those who remained on the starting dose (n=383); HR=1.37 (1.01–1.85), p=0.041. Median TTSP was 17.7 (13.5–23.7) and 14.7 (12.7–17.0) months, respectively; HR=1.26 (0.92–1.72), p=0.15.
Among 92 patients (19.2%) with brain metastases at baseline, median PFS was 10.9 (8.3–14.3) months, versus 12.4 (10.8–13.9) months in those without metastases (n=387); HR=1.23 (0.91–1.65), p=0.18. Median TTSP was 14.8 (12.7–20.7) and 15.4 (12.9–18.0) months, respectively; HR=1.0 (0.71–1.40), p=1.0.
8eea62084ca7e541d918e823422bd82e Conclusion
These findings demonstrate that tolerability-guided dose adjustment of afatinib is an effective measure to reduce treatment-related AEs, while maintaining therapeutic efficacy. TTSP was similar between patients with and without brain metastasis. This is additional evidence for the efficacy of afatinib in patients with brain metastases.
6f8b794f3246b0c1e1780bb4d4d5dc53
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P2.13 - Targeted Therapy (Not CME Accredited Session) (ID 962)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
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P2.13-21 - MET Addiction Can be Circumvented Through EGFR Inhibition Via AXL in MET-Amplified Primary Resistant EGFR-Mutant NSCLC (ID 14384)
16:45 - 18:00 | Author(s): Eng-Huat Tan
- Abstract
Background
Primary resistance to EGFR-TKI is observed in approximately 10% of patients with activating EGFR mutations. In a patient harboring L858R mutation and high cMET amplification (MET copy number 7.3, CEP7 ratio 3.4) who progressed after just 4 weeks of erlotinib (ERL), significant tumor regression was achieved with MET inhibition alone (Crizotinib, CRZ). We confirmed this phenotype in the corresponding patient-derived cell line model (A482) and identified EGFR-AXL interaction as a mechanism that can circumvent clonal cMET addiction.
a9ded1e5ce5d75814730bb4caaf49419 Method
We generated patient-derived cell lines from the patient’s baseline neck excision biopsy (A482) and evaluated the effect of mono and combination therapy (ERL, CRZ, ERL-CRZ) on A482, including viability (CellTiter-Glo Luminescent Assay, Promega), colony forming (Crystal Violet Assay), downstream signaling (Western blots) and adaptive pathways (Human Phosho-Receptor Tyrosine Kinase Array Kit, R&D systems). AXL was identified as a key mediator of resistance and subsequently subjected to further functional validation. Finally, we examined the prevalence of this clinical phenomenon in a retrospective series of MET amplified EGFR-mutant NSCLC.
4c3880bb027f159e801041b1021e88e8 Result
Cell viability assays confirmed the patient-derived cell line to be more sensitive to CRZ as compared to ERL alone or with combination CRZ-ERL. Upregulation of AXL, RET and FGFR3 expression were identified as adaptive changes 24 hours upon ERL exposure. A targeted pharmacologic screen revealed A482 to be exquisitely sensitive to combination EGFR and AXL inhibition. Immunoprecipitation revealed a direct interaction between EGFR and AXL, which upon treatment with ERL resulted in attenuation of cMET addiction. Co-existing cMET amplification with demonstrated suboptimal response to EGFR TKI was found in 3% of EGFR-mutant NSCLC in a retrospective series of patients.
8eea62084ca7e541d918e823422bd82e Conclusion
Targeting the EGFR-AXL axis through EGFR inhibition alone can lead to paradoxical MET pathway activation, while the combination of EGFR and AXL inhibition can circumvent downstream signaling in MET amplified EGFR-mutant NSCLC. AXL expression levels can potentially identify patients in whom combination or monotherapy with MET inhibitors may be most beneficial. Our data highlights the challenge in interpreting genomic alterations alone; and how cellular context can lead to differential sensitivities to EGFR and MET inhibitors alone and/or in combination in MET amplified EGFR-mutant NSCLC.
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