Patient harboring a novel PIK3CA point mutation after acquired resistance to crizotinib in an adenocarcinoma with ROS1 rearrangement: A case report and literature review

MYC promotes tyrosine kinase inhibitor resistance in ROS1 fusion-positive lung cancer

Targeted therapy of ROS1 fusion-driven non-small cell lung cancer (NSCLC) has achieved notable clinical success. Despite this, resistance to therapy inevitably poses a significant challenge. MYC amplification was present in ~19% of lorlatinib-resistant ROS1-driven NSCLC. We hypothesized that MYC overexpression drives ROS1-TKI resistance. Using complementary approaches in multiple models, including a MYC-amplified patient-derived cell line and xenograft (LUAD-0006), we established that MYC overexpression induces broad ROS1 TKI resistance. Pharmacological inhibition of ROS1 combined with MYC knockdown were essential to completely suppress LUAD-0006 cell proliferation compared to either treatment alone. We interrogated cellular signaling in ROS1-TKI resistant LUAD-0006 and discovered significant differential regulation of targets associated with cell cycle, apoptosis, and mitochondrial function. Combinatorial treatment of mitochondrial inhibitors with crizotinib revealed inhibitory synergism, suggesting increased reliance on glutamine metabolism and fatty-acid synthesis in chronic ROS1-TKI treated LUAD-0006 cells. In vitro experiments further revealed that CDK4/6 and BET bromodomain inhibitors effectively mitigate ROS1 TKI resistance in MYC-overexpressing cells. Notably, in vivo studies demonstrate that tumor control may be regained by combining ROS1 TKI and CDK4/6 inhibition. Our results contribute to the broader understanding of ROS1-TKI resistance in NSCLC. Implications: This study functionally characterizes MYC overexpression as a novel form of therapeutic resistance to ROS1 tyrosine kinase inhibitors in non-small-cell lung cancer and proposes rational combination treatment strategies.

Effectiveness of alectinib and osimertinib in a brain metastasized lung adenocarcinoma patient with concurrent EGFR mutations and DCTN1‐ALK fusion

The echinoderm microtubule associated protein‐like 4 gene (EML4) encodes the predominant anaplastic lymphoma kinase (ALK) fusion partner in non‐small‐cell lung cancer (NSCLC); however, the dynactin subunit 1 (DCTN1)‐ALK rearrangement is extremely rare. The co‐occurrence of primary epidermal growth factor receptor (EGFR) T790M mutation with EGFR exon 19 deletion (del) in patients with NSCLC is uncommon. Here we report a female lung adenocarcinoma patient with brain metastases and possible coexistence of primary EGFR T790M mutation/EGFR exon 19 del/DCTN1‐ALK translocation. The patient received multiline treatment including chemotherapy, antivascular, and targeted therapies. To overcome developed resistance to chemotherapy or targeted therapy to prolong overall survival, the patient's circulating tumor DNA (ctDNA) was dynamically monitored. The patient responded to successive osimertinib and alectinib treatment, and alectinib achieved a nearly complete response for lung and brain lesions after she acquired osimertinib resistance. Furthermore, we summarize 22 published cases of patients with lung adenocarcinoma with concurrent EGFR mutation and ALK rearrangement, including details of clinical characteristics, natural history, and pertinent therapy of this uncommon tumor subtype. This literature review shows that EGFR inhibition was an indispensable aspect of the treatment of patients with EGFR/ALK co‐alterations in the pre‐alectinib era and that ALK inhibition with crizotinib did not show more eye‐catching therapeutic results. Considering the effectiveness achieved by alectinib, this case study provides a new perspective for the treatment of lung cancer brain metastasis patients with concurrent EGFR/ALK mutations.

Comprehensive Molecular Analysis of Inflammatory Myofibroblastic Tumors Reveals Diverse Genomic Landscape and Potential Predictive Markers for Response to Crizotinib

PURPOSE

The European Organization for Research and Treatment of Cancer (EORTC) clinical phase II trial 90101 "CREATE" showed high antitumor activity of crizotinib, an inhibitor of anaplastic lymphoma kinase (ALK)/ROS1, in patients with advanced inflammatory myofibroblastic tumor (IMFT). However, recent findings suggested that other molecular targets in addition to ALK/ROS1 might also contribute to the sensitivity of this kinase inhibitor. We therefore performed an in-depth molecular characterization of archival IMFT tissue, collected from patients enrolled in this trial, with the aim to identify other molecular alterations that could play a role in the response to crizotinib.

EXPERIMENTAL DESIGN

Twenty-four archival IMFT samples were used for histopathological assessment and DNA/RNA evaluation to identify gene fusions, copy-number alterations (CNA), and mutations in the tumor tissue. Results were correlated with clinical parameters to assess a potential association between molecular findings and clinical outcomes.

RESULTS

We found 12 ALK fusions with 11 different partners in ALK-positive IMFT cases by Archer analysis whereas we did not identify any ROS1-rearranged tumor. One ALK-negative patient responding to crizotinib was found to have an ETV6-NTRK fusion in the tumor specimen. The CNA profile and mutational landscape of IMFT revealed extensive molecular heterogeneity. Loss of chromosome 19 (25% of cases) and PIK3CA mutations (9% of cases) were associated with shorter progression-free survival in patients receiving crizotinib.

CONCLUSIONS

We identified multiple genetic alterations in archival IMFT material and provide further insight into the molecular profile of this ultra-rare, heterogeneous malignancy, which may potentially translate into novel treatment approaches for this orphan disease.

Targeting Infrequent Driver Alterations in Non-Small Cell Lung Cancer

The discovery of oncogenic driver mutations led to the development of targeted therapies with non-small cell lung cancer (NSCLC) being a paradigm for precision medicine in this setting. Nowadays, the number of clinical trials focusing on targeted therapies for uncommon drivers is growing exponentially, emphasizing the medical need for these patients. Unfortunately, similar to what is observed with most targeted therapies directed against a driver oncogene, the clinical response is almost always temporary and acquired resistance to these drugs invariably emerges. Here, we review the biology of infrequent genomic actionable alterations in NSCLC as well as the current and emerging therapeutic options for these patients. Mechanisms leading to acquired drug resistance and future challenges in the field are also discussed.

Molecular and clinicopathological characteristics of ROS1-rearranged non-small-cell lung cancers identified by next-generation sequencing

ROS1 gene rearrangements have been reported in diverse cancer types including non-small-cell lung cancer (NSCLC), and with a notably higher prevalence in lung adenocarcinoma. The tyrosine kinase inhibitors, crizotinib, lorlatinib, and entrectinib, have demonstrated favorable efficacy in treating ROS1-rearranged NSCLCs. Herein, we retrospectively reviewed 17 158 NSCLC patients whose tumor specimen and/or circulating cell-free DNA underwent comprehensive genomic profiling. A total of 258 unique patients were identified with ROS1 rearrangements, representing an overall prevalence of approximately 1.5% of ROS1 fusions in newly diagnosed and relapsed NSCLC patients. CD74 (38%) was the most common fusion partner of ROS1, followed by EZR (13%), SDC4 (13%), SLC34A2 (10%), and other recurrent fusion partners with lower frequencies, including TPM3, MYH9, and CCDC6. Variant breakpoints occurred in ROS1 introns 33 (37%), 31 (25%), 32 (17%), and 34 (11%) with no obvious hotspots. CD74 (63%) and EZR (50%) were more frequently fused to ROS1 intron 33 than other introns, while ROS1 intron 31 was most frequently fused with SDC4 (79%) and SLC34A2 (81%). Crizotinib progression-free survival (PFS) was not significantly different between fusion variants involving breakpoints in different ROS1 introns, nor was there a significant difference in PFS between CD74-ROS1 and non-CD74-ROS1 groups of patients. Furthermore, TP53 was most frequently mutated in patients who progressed on crizotinib, and TP53 mutations were significantly associated with shorter crizotinib PFS. ROS1 mutations, including G2032R, were observed in approximately 33% of post-crizotinib samples. Collectively, we report the prevalence of ROS1 fusions in a large-scale NSCLC population and the efficacy of crizotinib in treating patients with ROS1-rearranged NSCLC.