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Hatim Husain
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P1.01 - Advanced NSCLC (ID 158)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2019, 09:45 - 18:00, Exhibit Hall
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P1.01-86 - Occurrence of de Novo Dual HER2/HER3 or HER2/EGFR TMD Mutations: Extending the Spectrum of Targetable Mono-HER2 TMD in NSCLC? (ID 956)
09:45 - 18:00 | Author(s): Hatim Husain
- Abstract
Background
HER2 (ERBB2) TMD mutations have recently been described as novel solo actionable drivers in NSCLC responsive to afatinib in small series. However, dual occurrence of de novo EGFR or HER3 (ERBB3) TMD mutations together with HER2 TMD mutations, which may have implications for dimerization patterns and treatment, has not been described.
Method
Hybrid-capture based comprehensive genomic profiling was performed on blood-based circulating tumor DNA (n=5,200) or FFPE tissue (n= 45,780) samples collected during clinical care from 50,980 unique NSCLC patients.
Result
HER2 TMD mutations were identified in 0.12% (60/50,980) of cases and included V659E (n=33), V659D (n=8), G660D (n=15), V659E+G660R, V659_I661>VVEGI, G660E>R, and S653C (1 each). Within this subset, the median age of patients was 61 years (range 33-91) and 62% were female. No co-occurring known NSCLC driver alterations were detected, except one case with EGFR exon 19 deletion and one case with EGFR L858R and lung co-primary tumors noted. However, co-occurring HER3 (I649R) or EGFR (G652R) TMD mutations were found in 18% (11/60) and 5.0% (3/60) of cases, respectively. Notably, these ERBB3 or EGFR TMD mutations only co-occurred with HER2 TMD V>D (8/9 cases) or G>D (7/15 cases), but not with V>E changes (0/34 cases; p=0.0002). HER2 amplification co-occurred with V659E in 15% (5/34) of cases, and G660D mutation was seen with the oncogenic extracellular domain S310F mutation in one case. Importantly, neither EGFR G652R nor ERBB3 I649R was found in the absence of a HER2 TMD mutation. Preliminary modelling studies suggest formation of a salt-bridge which would increase propensity for HER2/HER3 and HER2/EGFR heterodimerization favoring receptor activation. Two patients in this series with V659E were previously reported to have responded to afatinib and 1 patient with G660D+I649R did not respond to afatinib. Updated clinical data for these patients and others treated with HER2-tageted therapies will be presented.
Conclusion
HER2 TMD mutations (V659D/E or G660D/R) are uncommon but targetable driver alterations in NSCLC. In cases with HER2 TMD V>D or G>D, a de novo co-existing EGFR or HER3 TMD mutation was frequently observed (88% and 47%, respectively), which may explain differential dimerization preference and in turn response to ERBB inhibitors. We hypothesize that dual HER2/HER3 or HER2/EGFR TMD mutants may be more aggressive than single HER2 TMD mutants due to the arginine-aspartic acid interaction, and these dual mutants may require combined kinase inhibitor + antibody therapy to block dimerization. Studies utilizing models to further characterization these co-alterations are in progress.
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P2.14 - Targeted Therapy (ID 183)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Targeted Therapy
- Presentations: 1
- Moderators:
- Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
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P2.14-24 - An Open-Label Randomized Phase II Study of Combining Osimertinib With and Without Ramucirumab in TKI-Naïve EGFR-Mutant Metastatic NSCLC (ID 851)
10:15 - 18:15 | Author(s): Hatim Husain
- Abstract
Background
Osimertinib, a third-generation EGFR inhibitor, has become the first-line therapy for patients with metastatic EGFR-mutant NSCLCs since 2018. Osimertinib is well-tolerated, therefore, it opens opportunities to be combined with other therapeutic agents to enhance the treatment outcome. In preclinical models, it has been shown that upregulated VEGF signaling mediates acquired resistance to EGFR therapies. In xenograft models, combination of anti-VEGF medications with EGFR inhibitors were significantly more effective than erlotinib or gefitinib alone. Ramucirumab, a monoclonal antibody targeting VEGF receptor 2, is approved with docetaxel in as second line treatment for NSCLCs. In clinical trial evaluations, the phase 3 RELAY trial (NCT02411448) studying ramucirumab plus erlotinib in patients with metastatic untreated EGFR-mutant NSCLC patients showed a statistically significant improvement in progression-free survival in the combination group compared to erlotinib alone. A phase I study of osimertinib with ramucirumab (NCT02789345) demonstrated safety and feasibility of this combination. With strong preclinical and clinical evidence showing dual inhibition of VEGF/EGFR signaling prolongs progression-free survival for EGFR-mutant lung cancers, and demonstrated safety, we are conducting a phase 2 trial to evaluate the osimertinib ramucirumab combination’s efficacy in treatment-naïve EGFR-mutant NSCLC.
Method
The OSI+RAM trial is a randomized phase 2 study with the primary endpoint being progression-free survival in osi+ram group as compared to osimertinib monotherapy group. The major inclusion criteria include patients with metastatic NSCLC harboring EGFR mutations (L858R/Exon 19 del). The major exclusion criteria include prior anti-EGFR or anti-VEGF treatments. Patients with stable CNS metastasis are allowed. Based on the results from erlotinib bevacizumab (NEJ026) study, we expect an improvement of PFS from 18.9 months to 29.7 months, corresponding to a hazard ratio of 0.65. The trial plans to enroll total of 150 patients, with 100 allocating to osi+ram arm and 50 to osimertinib monotherapy. Total of 9 study sites in the USA are planned. Hoosier Cancer Research Network will facilitate the execution of the trial. The trial protocol has received IND exemption from US FDA and has been approved by IRB at MD Anderson Cancer Center. The first subject is expected to be enrolled in May 2019. A planned interim analysis will be performed after the first 75 subjects are enrolled. NCT03909334.
Result
Section not applicable
Conclusion
Section not applicable
