A Changing of the Guard: Immune Checkpoint Inhibitors With and Without Chemotherapy as First Line Treatment for Metastatic Non-small Cell Lung Cancer

Inhibitory antibodies targeting programmed death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) have resulted in improved outcomes for many patients with metastatic non-small cell lung cancer in (NSCLC) in the second-line setting due to their ability to lead to prolonged anti-tumor immune responses. Combining these immunotherapies with platinum-based chemotherapy as first-line treatment has resulted in improved response rates and increased survival when compared to platinum-based chemotherapy alone. Certain patient populations may even benefit from immune checkpoint inhibitors as monotherapy in the first-line setting. The PD-1 inhibitor pembrolizumab is approved as monotherapy or in combination with platinum + pemetrexed for most newly diagnosed patients with metastatic NSCLC, excluding those with a targetable oncogene such as ALK and EGFR. The PD-L1 inhibitor atezolizumab is also approved in combination with bevacizumab + carboplatin + paclitaxel for the same population, with some parts of the world also approving this regimen for patients with ALK rearrangements or EGFR activating mutations. However, there are many other chemo-immunotherapy regimens that have been evaluated as initial treatment in metastatic NSCLC. Additionally, combinations of PD-1 axis inhibitors with cytotoxic T lymphocyte antigen-4 inhibitors have been examined, although none are yet approved. Here we review the clinical data in support of the current first-line approaches across histologies and biomarker subtypes, as well as highlight future research directions revealed by the current data

Rapidly Acquired Resistance to EGFR Tyrosine Kinase Inhibitors in NSCLC Cell Lines through De-Repression of FGFR2 and FGFR3 Expression

Despite initial and sometimes dramatic responses of specific NSCLC tumors to EGFR TKIs, nearly all will develop resistance and relapse. Gene expression analysis of NSCLC cell lines treated with the EGFR TKI, gefitinib, revealed increased levels of FGFR2 and FGFR3 mRNA. Analysis of gefitinib action on a larger panel of NSCLC cell lines verified that FGFR2 and FGFR3 expression is increased at the mRNA and protein level in NSCLC cell lines in which the EGFR is dominant for growth signaling, but not in cell lines where EGFR signaling is absent. A luciferase reporter containing 2.5 kilobases of fgfr2 5′ flanking sequence was activated after gefitinib treatment, indicating transcriptional regulation as a contributing mechanism controlling increased FGFR2 expression. Induction of FGFR2 and FGFR3 protein as well as fgfr2-luc activity was also observed with Erbitux, an EGFR-specific monoclonal antibody. Moreover, inhibitors of c-Src and MEK stimulated fgfr2-luc activity to a similar degree as gefitinib, suggesting that these pathways may mediate EGFR-dependent repression of FGFR2 and FGFR3. Importantly, our studies demonstrate that EGFR TKI-induced FGFR2 and FGFR3 are capable of mediating FGF2 and FGF7 stimulated ERK activation as well as FGF-stimulated transformed growth in the setting of EGFR TKIs. In conclusion, this study highlights EGFR TKI-induced FGFR2 and FGFR3 signaling as a novel and rapid mechanism of acquired resistance to EGFR TKIs and suggests that treatment of NSCLC patients with combinations of EGFR and FGFR specific TKIs may be a strategy to enhance efficacy of single EGFR inhibitors

Entrectinib in locally advanced or metastatic ROS1 fusion-positive non-small cell lung cancer (NSCLC): Integrated analysis of ALKA-372-001, STARTRK-1 and STARTRK-2

Background Entrectinib is a potent inhibitor of ROS1 (in addition to TRKA/B/C), designed to effectively penetrate the central nervous system (CNS); brain metastases are common in patients with advanced ROS1 fusion-positive NSCLC. Entrectinib achieves therapeutic levels in the CNS with antitumor activity in multiple intracranial tumor models. We present an updated integrated safety and efficacy analysis from three Phase I/II studies of entrectinib (ALKA-372-001 [EudraCT 2012-000148-88], STARTRK-1 [NCT02097810], STARTRK-2 [NCT02568267]) in patients with locally advanced or metastatic ROS1 fusion-positive NSCLCs. Methods The analysis included patients with ROS1 inhibitor-naive NSCLC harboring a ROS1 fusion identified via nucleic acid-based diagnostic platforms. The ROS1 safety-evaluable population included patients with ROS1 fusion-positive NSCLC who received ≥1 dose of entrectinib; the integrated efficacy analysis included patients with at least 6 months of follow-up. Tumor assessments were done at week 4 and every 8 weeks thereafter. Blinded independent central review (BICR), RECIST v1.1 was performed. Primary endpoints by BICR: overall response rate (ORR) and duration of response (DOR). Key secondary endpoints: progression-free survival (PFS), safety. Additional endpoints: intracranial ORR (complete/partial responses), DOR in patients with an intracranial response, PFS in patients with baseline CNS disease. Results In the ROS1 safety-evaluable population (n=134), at least one treatment-related AE (TRAE) of any grade was seen in 93% of patients. Patients with at least one TRAE by highest grade were: grade 1/2, 59%; grade 3, 31%; grade 4, 4%. There were no grade 5 TRAEs. TRAEs led to dose reduction or discontinuation in 34% and 5% of patients, respectively. In the efficacy-evaluable population (n=53 patients with treatment-naive, ROS1 fusion-positive NSCLC; median age 53 years, 64% female, 59% never smokers), BICR-assessed ORR was 77% (95% CI 64-88), complete responses n=3 (6%). Median BICR-assessed DOR: 25 mo (95% CI 11-35). Median BICR-assessed PFS: 26 mo (95% CI 16-37) and 14 mo (95% CI 5-NR) for patients without (n=30) and with CNS disease (n=23) at baseline, respectively. In patients with baseline CNS disease (per BICR assessment, n=20), intracranial ORR was 55% (95% CI 32-77) and median intracranial DOR in patients with an intracranial response (n=11) was 13 mo (95% CI 6-not reached). Conclusion Entrectinib is highly active in patients with ROS1 fusion-positive NSCLC, including those with CNS disease. Entrectinib is well tolerated and has a manageable safety profile. Citation Format: Alexander Drilon, Fabrice Barlesi, Filippo De Braud, Byoung Chul Cho, Myung-Ju Ahn, Salvatore Siena, Matthew G. Krebs, Chia-Chi Lin, Tom John, Daniel SW Tan, Takashi Seto, Rafal Dziadziuszko, Hendrick-Tobias Arkenau, Christian Rolfo, Jurgen Wolf, Chenglin Ye, Todd Riehl, Susan Eng, Robert C. Doebele. Entrectinib in locally advanced or metastatic ROS1 fusion-positive non-small cell lung cancer (NSCLC): Integrated analysis of ALKA-372-001, STARTRK-1 and STARTRK-2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT192

GATA3 and MDM2 are synthetic lethal in estrogen receptor-positive breast cancers.

Synthetic lethal interactions, where the simultaneous but not individual inactivation of two genes is lethal to the cell, have been successfully exploited to treat cancer. GATA3 is frequently mutated in estrogen receptor (ER)-positive breast cancers and its deficiency defines a subset of patients with poor response to hormonal therapy and poor prognosis. However, GATA3 is not yet targetable. Here we show that GATA3 and MDM2 are synthetically lethal in ER-positive breast cancer. Depletion and pharmacological inhibition of MDM2 significantly impaired tumor growth in GATA3-deficient models in vitro, in vivo and in patient-derived organoids/xenograft (PDOs/PDX) harboring GATA3 somatic mutations. The synthetic lethality requires p53 and acts via the PI3K/Akt/mTOR pathway. Our results present MDM2 as a therapeutic target in the substantial cohort of ER-positive, GATA3-mutant breast cancer patients. With MDM2 inhibitors widely available, our findings can be rapidly translated into clinical trials to evaluate in-patient efficacy

ERBB family fusions are recurrent and actionable oncogenic targets across cancer types

PurposeGene fusions involving receptor tyrosine kinases (RTKs) define an important class of genomic alterations with many successful targeted therapies now approved for ALK, ROS1, RET and NTRK gene fusions. Fusions involving the ERBB family of RTKs have been sporadically reported, but their frequency has not yet been comprehensively analyzed and functional characterization is lacking on many types of ERBB fusions.Materials and methodsWe analyzed tumor samples submitted to Caris Life Sciences (n=64,354), as well as the TCGA (n=10,967), MSK IMPACT (n=10,945) and AACR GENIE (n=96,324) databases for evidence of EGFR, ERBB2 and ERBB4 gene fusions. We also expressed several novel fusions in cancer cell lines and analyzed their response to EGFR and HER2 tyrosine kinase inhibitors (TKIs).ResultsIn total, we identified 1,251 ERBB family fusions, representing an incidence of approximately 0.7% across all cancer types. EGFR, ERBB2, and ERBB4 fusions were most frequently found in glioblastoma, breast cancer and ovarian cancer, respectively. We modeled two novel types of EGFR and ERBB2 fusions, one with a tethered kinase domain and the other with a tethered adapter protein. Specifically, we expressed EGFR-ERBB4, EGFR-SHC1, ERBB2-GRB7 and ERBB2-SHC1, in cancer cell lines and demonstrated that they are oncogenic, regulate downstream signaling and are sensitive to small molecule inhibition with EGFR and HER2 TKIs.ConclusionsWe found that ERBB fusions are recurrent mutations that occur across multiple cancer types. We also establish that adapter-tethered and kinase-tethered fusions are oncogenic and can be inhibited with EGFR or HER2 inhibitors. We further propose a nomenclature system to categorize these fusions into several functional classes

A framework for understanding and targeting residual disease in oncogene-driven solid cancers

Molecular targeted therapy has the potential to dramatically improve survival in patients with cancer. However, complete and durable responses to targeted therapy are rare in individuals with advanced-stage solid cancers. Even the most effective targeted therapies generally do not induce a complete tumor response, resulting in residual disease and tumor progression that limits patient survival. We discuss the emerging need to more fully understand the molecular basis of residual disease as a prelude to designing therapeutic strategies to minimize or eliminate residual disease so that we can move from temporary to chronic control of disease, or a cure, for patients with advanced-stage solid cancers. Ultimately, we propose a shift from the current reactive paradigm of analyzing and treating acquired drug resistance to a pre-emptive paradigm of defining the mechanisms that result in residual disease, to target and limit this disease reservoir