Virtual Library

Start Your Search

Monique Nilsson



Author of

  • +

    MA09 - EGFR & MET (ID 128)

    • Event: WCLC 2019
    • Type: Mini Oral Session
    • Track: Targeted Therapy
    • Presentations: 1
    • Now Available
    • +

      MA09.03 - Identification of Mechanisms of Acquired Resistance to Poziotinib in EGFR Exon 20 Mutant Non-Small Cell Lung Cancer (NSCLC) (Now Available) (ID 2904)

      15:15 - 16:45  |  Author(s): Monique Nilsson

      • Abstract
      • Presentation
      • Slides

      Background

      Insertions/mutations in exon 20 of EGFR occur in ~2% Insertions/mutations in exon 20 of EGFR occur in ~2% of all lung adenocarcinomas. These alterations are characterized by primary resistance to approved tyrosine kinase inhibitors (TKIs) with response rates of <12%. We have shown that exon 20 insertions restrict the size of the drug-binding pocket, limiting binding of large inhibitors. However, poziotinib can circumvent these steric changes and is a potent inhibitor of EGFR exon 20 mutants. In our investigator-initiated phase 2 trial of EGFR exon 20 mutant NSCLC, poziotinib was associated with a best objective response rate of 55% (Heymach et al, 19th WCLC). Herein, we use preclinical models and clinical samples from our phase 2 study to identify mechanisms of acquired poziotinib resistance (NCT03066206).

      Method

      EGFR exon 20 insertion (D770insNPG) genetically engineered mice (GEM) were treated with poziotinib until progression. Upon progression, tumor DNA and protein were analyzed using whole exome sequencing (WES) and reverse phase protein assay (RPPA). Mandatory and optional biopsies were obtained at baseline and progression, respectively, from patients treated in our phase 2 trial of poziotinib in EGFR exon 20 mutant NSCLC. Serial cfDNA was collected at baseline, 8 weeks of therapy, and on progression. Patient samples were analyzed using targeted next generation sequencing or WES.

      Result

      Poziotinib acquired-resistance GEM tumors acquired mutations in ErbB4, KRAS, and other genes which represent potential targetable bypass pathways. Resistant GEM tumors displayed increased activation of MAPK, AKT, ERK and MEK compared to sensitive tumors, suggesting that poziotinib acquired resistance is associated with reactivation of the MAPK/PI3K pathways. We enrolled 50 EGFR exon 20 mutant patients in our phase 2 trial. Analysis of matched pre-poziotinib and on-progression samples from 20 responding patients revealed acquired EGFR tyrosine kinase domain point mutations in 4 patients (T790M (2), V774A (1), D770A, (1)). Ba/F3 cells co-expressing EGFR exon 20 insertion (S768supSVD) and T790M were resistant to poziotinib, suggesting that T790M is a poziotinib resistance driver. Potential acquired EGFR-independent resistance mechanisms identified in patients to date include PIK3CA E545K (1), MAP2K2 S94L (1), MET amplification (1), EGFR amplification (2), and CDK6 amplification (2).

      Conclusion

      Parallel to acquired resistance mechanisms seen in classical EGFR mutation, acquired resistance to poziotinib can be mediated through EGFR-dependent mechanisms, notably T790M and other EGFR tyrosine kinase domain point mutations. EGFR-independent resistance mechanisms include activation of bypass pathways. Preclinical validation of resistance mechanisms and additional analysis of patient samples will be presented at the meeting.

      Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.

      Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.

  • +

    MA17 - Molecular Mechanisms and Therapies (ID 143)

    • Event: WCLC 2019
    • Type: Mini Oral Session
    • Track: Biology
    • Presentations: 1
    • Now Available
    • +

      MA17.10 - Lactate Transporter Blockade as a Strategy to Overcome VEGF Inhibitor-Resistance in LKB1-Deficient NSCLC (Now Available) (ID 2647)

      15:45 - 17:15  |  Author(s): Monique Nilsson

      • Abstract
      • Presentation
      • Slides

      Background

      STK11/LKB1 alterations are found in 20-30% of NSCLC and used to co-occur with KRAS mutations. Because LKB1 activates AMPK, many of the best known functions of LKB1 are attributed to its ability to control metabolic alterations in cells. Our laboratory have previously reported that loss of LKB1 promotes enhanced glycolysis and elevated lactate production and more recently we demonstrated that STK11/LKB1 mutations are the strongest predictors of de novo resistance to immunotherapy in NSCLC. Prior studies have revealed an association between alterations in the LKB1/AMPK pathway and worse clinical outcomes in NSCLC and in patients treated with chemotherapy and bevacizumab. Given the roles of LKB1 in the regulation of cell metabolism and resistance to immunotherapy, it is feasible that LKB1 also impacts on the response to anti-angiogenic therapies.

      Method

      Xenograft mouse models were established by subcutaneous injection of H460 cells (LKB1-deficient) and H460 LKB1-expressing in nude mice and LKR10 (KRASG12D) LKB1 wild-type (K) or LKB1- knockout (KL) into 129Svmice. Mice were randomized to vehicle or B20-4.1.1 anti-VEGF antibody. Glycolytic activity of LKB1-intact and -deficient NSCLC cells was measured by Seahorse assay. We analyzed gene expression of SLC16A3 (MCT4) by qPCR and Western blot. Genetic disruption of MCT4 in the K and KL cell lines was done using CRISPR-Cas9 and mouse models were established by subcutaneous injection into mice.

      Result

      Mice bearing LKB1-expressing H460 xenografts treated with anti-VEGF antibody showed a significant decrease in tumor volume (p<0.05) compared with their vehicle-treated counterparts. However, mice bearing LKB1-deficient H460 xenografts showed markedly reduced efficacy of anti-VEGF therapy compared with that in LKB1-expressing xenografts. Anti-VEGF therapy significantly reduced growth of LKR10 K tumors (p<0.001) but not in LKR10 KL tumors. Microvascular density was not increased in KL tumors following anti-VEGF treatment compared to K. Human isogenic LKB1-deficient cells showed a significantly increased rate of glycolysis and lactate secretion compared with cells expressing LKB1. Human and murine LKB1-deficient cells also had increased MCT4 expression compared to K cells. Immunofluorescence and RPPA analysis of tumor samples from the K and KL mouse models showed that KL tumors upregulated MCT4 protein expression compared with K tumors (p<0.0001). The genetic disruption of MCT4 KL tumors significantly improved tumor volume reduction to anti-VEGF therapies in vivo (p<0.001).

      Conclusion

      LKB1 loss is associated with increased lactate secretion and resistance to VEGF inhibition in NSCLC. The targeting of the lactate transporter MCT4 enhance the sensitivity of LKB1-deficient NSCLC to anti-VEGF therapy.

      Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.

      Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.

  • +

    P1.14 - Targeted Therapy (ID 182)

    • Event: WCLC 2019
    • Type: Poster Viewing in the Exhibit Hall
    • Track: Targeted Therapy
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/08/2019, 09:45 - 18:00, Exhibit Hall
    • +

      P1.14-08 - Activity of Poziotinib and Other 2nd-Gen Quinazoline EGFR TKIs in Atypical Exon18 and Acquired Osimertinib Resistance Mutants (ID 2694)

      09:45 - 18:00  |  Author(s): Monique Nilsson

      • Abstract

      Background

      In EGFR, exon 18 encodes for the P-loop (L718-V726), and mutations in this region (G719S/A, L718Q/V, G724S) are known to reduce sensitivity to osimertinib and first-generation EGFR TKIs. Osimertinib resistance is associated with a number of acquired mutations in exons 19 and 20 (S784F, L747S, C797S and L792H). We investigated the frequency and drug sensitivity of these and other osimertinib-resistant EGFR mutations

      Method

      We generated ~50 different Ba/F3 cell line models expressing classical and/or atypical EGFR mutations (exons 18-21) and evaluated the transforming ability and sensitivity to 14 EGFR TKIs including non-covalent (first-generation), afatinib, dacomitinib, and poziotinib (quinazoline and covalent, second-generation), and covalent T790M-specific (third-generation) inhibitors. Impact of atypical mutations was analyzed by in silico modeling.

      Result

      We found 3.6% (N=32/895) of EGFR-mutant patients had atypical, exon 18, P-loop mutations in the MD Anderson GEMINI database. Modeling of classical EGFR mutations revealed osimertinib has distinct interactions between the solvent front of osimertinib and residues within the P-loop of EGFR, whereas second-generation quinazoline TKIs, such as poziotinib, extend into the pocket, near T790, lacking these interactions. Mutations in the P-loop were predicted to shift osimertinib out of alignment with V726 and F723, causing resistance to osimertinib but not quinazoline-based TKIs. Atypical exon 18 mutations (G719S/A, L718Q/V, G724S) had IC50 values of 113.6nM, 1.6nM, and 137.5nM for first-, second-, and third-generation TKIs, respectively. Second-generation TKIs inhibited G719S/A-T790M mutations at concentrations 2-fold lower than third-generation TKIs (IC50 = 23.4nM and 46nM). Osimertinib-resistance mutations (L747S, S784F, C797S, L792H) co-occurring with classical sensitizing mutations (L858R or ex19del) had IC50 values of 56.8nM, 1.4nM, and 996nM to first, second and third-generation inhibitors. Of the second-generation TKIs tested, poziotinib was the most potent for atypical exon 18 P-loop mutations; G719S/A-T790M mutations; and classical mutants with acquired osimertinib-resistance mutations (IC50= 0.4nM, 3.2nM, 0.8nM).

      Conclusion

      Exon 18 atypical P-loop mutations and osimertinib-resistance mutations demonstrated high sensitivity to second-generation quinazoline TKIs, compared to first- and third-generation inhibitors. Mutations in the P-loop of EGFR confer resistance to third-generation TKIs by destabilizing solvent front interactions of the molecule, and osimertinib-resistance mutations interfere with covalent binding at C797. Second-generation TKIs, especially poziotinib, are potent inhibitors of these mutations because they have increased hydrophobic interactions at the back of the drug binding cleft that are retained without covalent binding. Together, these data indicate that poziotinib and other second-generation TKIs may be useful for the treatment of NSCLC patients with atypical P-loop and selected osimertinib-resistant EGFR mutations.

  • +

    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
    • +

      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): Monique Nilsson

      • 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