Crizotinib-resistant Mutations Research Articles

Establishment of an acquired lorlatinib-resistant cell line of non-small cell lung cancer and its mediated resistance mechanism.

Although lorlatinib, the third generation of echinoderm microtubule protein 4-anaplastic lymphoma kinase (EML4-ALK) tyrosine kinase inhibitor (TKI), overcame the previous generation ALK-TKIs' drug resistance problems, but the mechanism of lorlatinib resistance remained unclear. Furthermore, optimal chemotherapy for lorlatinib-resistant non-small cell lung cancer (NSCLC) patients was still unknown. A lorlatinib-resistant NSCLC cell line SNU-2535LR was generated by gradually increasing dose of lorlatinib to crizotinib-resistant cell line SNU-2535 in vitro. To study the resistance mechanism of SNU-2535LR cells, we applied CCK-8 assay to detect the sensitivity of crizotinib and the reverse effect of APR-246, a p53 activator, on lorlatinib-induced resistance and different chemotherapy drugs to SNU-2535LR cells. We also detected the expressions of EML4-ALK-related proteins of SNU-2535LR cells via western blot.Please confirm that author names have been identified correctly and are presented in the right order.Dear Editor: I have carefully confirmed that the author names have been identified correctly and are presented in right order.Thank you very much! Your sincerely BoXie RESULTS: The sensitivity of SNU-2535LR cells to lorlatinib was decreased significantly than that of SNU-2535 cells. EML4-ALK fusion was decreased both at protein level and DNA level in SNU-2535LR cells. More interesting, the crizotinib-resistant mutation ALK p.G1269A disappeared, while new TP53 mutation emerged in SNU-2535LR cells. APR-246 can reverse the lorlatinib resistance in SNU-2535LR cells, with a reversal index of 4.768. Compared with SNU-2535 cells, the sensitivity of SNU-2535LR cells to gemcitabine, docetaxel and paclitaxel was significantly increased (P < 0.05), but decreased to cisplatin (P < 0.05). This study demonstrated that the combination of p53 protein agonist and lorlatinib may provide a new therapeutic strategy for NSCLC patients with lorlatinib resistance and TP53 mutation. Furthermore, the results also provide guidance for selecting optimal chemo-regimens for NSCLC patients after ALK-TKIs failure.

Discovery and preclinical evaluations of WX-0593, a novel ALK inhibitor targeting crizotinib-resistant mutations

ALK gene rearrangements are oncogenic drivers in approximately 5% of NSCLC. Crizotinib, a first generation ALK inhibitor, is widely prescribed for ALK-positive NSCLC in clinic. Resistance to crizotinib and other ALK inhibitors has been problematic. Addressing resistance, here we describe discovery and development of a novel, proprietary spirocyclic diamine-substituted aryl phosphine oxide series of inhibitors, which led to the identification of WX-0593 (16a) as a potent ALK inhibitor. WX-0593 inhibited the activity of both wild type and resistant mutants of ALK in vitro, showed strong antitumor activity in a crizotinib-resistant mouse PDX model. WX-0593 is currently under development in phase II/III clinical trials.

A new ALK inhibitor overcomes resistance to first- and second-generation inhibitors in NSCLC.

More than 60% of nonsmall cell lung cancer (NSCLC) patients show a positive response to the first ALK inhibitor, crizotinib, which has been used as the standard treatment for newly diagnosed patients with ALK rearrangement. However, most patients inevitably develop crizotinib resistance due to acquired secondary mutations in the ALK kinase domain, such as the gatekeeper mutation L1196M and the most refractory mutation, G1202R. Here, we develop XMU‐MP‐5 as a new‐generation ALK inhibitor to overcome crizotinib resistance mutations, including L1196M and G1202R. XMU‐MP‐5 blocks ALK signaling pathways and inhibits the proliferation of cells harboring either wild‐type or mutant EML4‐ALK in vitro and suppresses tumor growth in xenograft mouse models in vivo. Structural analysis provides insights into the mode of action of XMU‐MP‐5. In addition, XMU‐MP‐5 induces significant regression of lung tumors in two genetically engineered mouse (GEM) models, further demonstrating its pharmacological efficacy and potential for clinical application. These preclinical data support XMU‐MP‐5 as a novel selective ALK inhibitor with high potency and selectivity. XMU‐MP‐5 holds great promise as a new therapeutic against clinically relevant secondary ALK mutations.

ROS1 Fusion Mediates Immunogenicity by Upregulation of PD-L1 After the Activation of ROS1–SHP2 Signaling Pathway in Non-Small Cell Lung Cancer

The drug resistance of first-line crizotinib therapy for ROS proto-oncogene 1, receptor tyrosine kinase (ROS1) fusion non-small cell lung cancer (NSCLC) is inevitable. Whether the administration of immune checkpoint inhibitor (ICI) therapy is suitable for ROS 1 fusion NSCLCs or after the development of crizotinib resistance is still unknown. In this study, five different crizotinib resistant concentration cell lines (HCC78CR1-5) from primary sensitive HCC78 cells were cultured. Ba/F3 cells expressing crizotinib sensitive ROS1 fusion and crizotinib resistant ROS1-G2032R mutation were used to explore the relationship between ROS1 fusion, ROS1-G2032R mutation and programmed death-ligand 1 (PD-L1) expression and the clinical potential of anti-PD-L1 ICI therapy. The signaling pathway net was compared between HCC78 and HCC78CR1-5 cells using RNA sequencing. Anti- PD-L1 ICI therapy was performed on mouse xenograft models with Ba/F3 ROS1 fusion or ROS1-G2032R mutation. HCC78CR1-5 showed more immunogenicity than HCC78 in immune-related pathways. The PD-L1 expression level was remarkably higher in HCC78CR1-5 with ROS1 fusion upregulation than HCC78 primary cell. Furthermore, the expression of PD-L1 was down-regulated by RNA interference with ROS1 siRNAs and up-regulated lower in Ba/F3 ROS1-G2032R resistant mutation than ROS1 fusion. Western blotting analysis showed the ROS1–SHP2 signaling pathway activation in HCC78CR1-5 cells, Ba/F3 ROS1 fusion and ROS1-G2032R resistant mutation. Mouse xenograft models with Ba/F3 ROS1 fusion showed more CD3+PD-1+ T cells both in blood and tissue, and more sensitivity than the cells with Ba/F3 ROS1-G2032R resistant mutation after anti-PD-L1 therapy. Our findings indicate that PD-L1 upregulation depends on ROS1 fusion more than ROS1-G2032R mutation. We share our insights of NSCLCs treatment management into the use of anti-PD-L1 ICI therapy in ROS1 fusion and not in ROS1-G2032R resistant mutation.

SAF-189s, a potent new-generation ROS1 inhibitor, is active against crizotinib-resistant ROS1 mutant-driven tumors.

The ROS1 fusion kinase is an attractive antitumor target. Though with significant clinical efficacy, the well-known first-generation ROS1 inhibitor (ROS1i) crizotinib inevitably developed acquired resistance due to secondary point mutations in the ROS1 kinase. Novel ROS1is effective against mutations conferring secondary crizotinib resistance, especially G2032R, are urgently needed. In the present study, we evaluated the antitumor efficacy of SAF-189s, the new-generation ROS1/ALK inhibitor, against ROS1 fusion wild-type and crizotinib-resistant mutants. We showed that SAF-189s potently inhibited ROS1 kinase and its known acquired clinically resistant mutants, including the highly resistant G2032R mutant. SAF-189s displayed subnanomolar to nanomolar IC50 values against ROS1 wild-type and mutant kinase activity and a selectivity vs. other 288 protein kinases tested. SAF-189s blocked cellular ROS1 signaling, and in turn potently inhibited the cell proliferation in HCC78 cells and BaF3 cells expressing ROS1 fusion wild-type and resistance mutants. In nude mice bearing BaF3/CD74-ROS1 or BaF3/CD74-ROS1G2032R xenografts, oral administration of SAF-189s dose dependently suppressed the growth of both ROS1 wild-type- and G2032R mutant-driven tumors. In a patient-derived xenograft model of SDC4-ROS1 fusion NSCLC, oral administration of SAF-189s (20 mg/kgevery day) induced tumor regression and exhibited notable prolonged and durable efficacy. In addition, SAF-189s was more potent than crizotinib and comparable to lorlatinib, the most advanced ROS1i known against the ROS1G2032R. Collectively, these results suggest the promising potential of SAF-189s for the treatment of patients with the ROS1 fusion G2032R mutation who relapse on crizotinib. It is now recruiting both crizotinib-relapsed and naive ROS1-positive NSCLC patients in a multicenter phase II trial (ClinicalTrials.gov Identifier: NCT04237805).

Fragment-based modification of 2,4-diarylaminopyrimidine derivatives as ALK and ROS1 dual inhibitors to overcome secondary mutants

In order to explore novel ALK and ROS1 dual inhibitors capable of overcoming crizotinib-resistant mutants, two series of 2,4-diarylaminopyrimidine derivatives were designed, synthesized and evaluated for their in vitro cytotoxic activity. In this work, we retained the 2,4-diarylaminopyrimidine scaffold and derivatize the DAAP scaffold with sulfonyl and acrylamide moieties to extend the structure–activity relationship (SAR) study. To our delight, some compounds exhibited excellent inhibitory activity with a double-digit nanomolar level in MTT assay. Four compounds were selected for enzymic assays further, the results led to the identification of a potent ALK and ROS1 dual inhibitor X-17, with IC50 values of 3.7 nM, 2.3 nM, 8.9 nM and 1.9 nM against ALK, ALKL1196M, ALKG1202R and ROS1, respectively. Ultimately, the molecular docking studies on X-17 clearly disclosed reasonable and optimal binding interactions with ALK.

Abstract C084: Crizotinib resistance mechanisms and potential therapeutic strategies to overcome the resistance in ROS1-rearranged non-small cell lung cancer

Abstract ROS1 rearrangement was observed in about 1 % of NSCLC patients and in several other cancers such as cholangiocarcinoma, glioblastoma, or colorectal cancer. To date, crizotinib, an ALK/ROS1 inhibitor was approved and widely used for the treatment of ROS1 rearranged NSCLC. However, the tumor relapses within a few years due to the emergence of crizotinib resistance by the secondary mutations in ROS1 kinase domain (e.g. G2032R) or other unidentified mechanisms. In this study, we explored crizotinib resistance mechanisms using ENU mutagenesis screening and the analysis of crizotinib resistant patient’s pleural effusion. We found several secondary mutations in ROS1 kinase domain including previously reported mutations. From a crizotinib resistant patient’s specimen, no secondary mutation in ROS1 was observed. By establishing a cell line from the specimen, we performed kinase inhibitor screening combined with crizotinib, and found that a combination of crizotinib with dasatinib or a few other tyrosine kinase inhibitors can suppress the growth. These results suggested that a bypass pathway mediated resistance through Src family kinase conferred resistance in this crizotinib resistant case. For overcoming the secondary ROS1 mutations mediated crizotinib resistance, we characterized several ROS1 inhibitors including a new selective ROS1/NTRK inhibitor DS-6051b in preclinical models of ROS1-rarranged cancers by newly establishing cell lines from TKI naïve ROS1 fusion positive NSCLC patients, or developing resistant mutation harboring HCC78 (SCL34A2-ROS1) or Ba/F3-CD74-ROS1 cell line models. Using these preclinical models, we demonstrated that DS-6051b induced dramatic growth inhibition of both wild type and G2032R mutant ROS1–rearranged cancers in vitro and in vivo, suggesting that DS-6051b might be effective in treating wildtype and crizotinib resistant mutant ROS1-rearranged lung cancer. This study revealed that potential resistance mechanisms in ROS1-rearranged NSCLC are similar to those identified in ALK rearranged NSCLC, and next-generation ROS1 inhibitor provides future promising therapeutic strategies to overcome the secondary mutation mediated resistance. Citation Format: Ryohei Katayama, Bo Gong, Makoto Nishio, Naoya Fujita. Crizotinib resistance mechanisms and potential therapeutic strategies to overcome the resistance in ROS1-rearranged non-small cell lung cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C084. doi:10.1158/1535-7163.TARG-19-C084

I.17 ALK Genomic Aberrations in NSCLC and Clinical Implications

Anaplastic Lymphoma Kinase (ALK) genomic aberrations in NSCLC was one of the first genomic aberrations, which was successfully targeted with specific drug, e.g. crizotinib, and led to rapid development of personalized therapy in NSCLC. Crizotinib as single agent showed remarkable response (70-80%) in patients with advanced NSCLC, who had the EML-4/ALK- translocation, which occurs in 2-5% of the patients. The genomic abnormality was originally diagnosed by FISH using a defined criterion (split- apart FISH pattern in at least 15% of the cells). However, later the US FDA also approved ALK-IHC for diagnosis using the Ventana ALK-specific antibody, D5F3). Today, this genomic abnormality is mostly detected by NGS. Not only was crizotinib associated to high response rate, but also to long-term outcomes (Solomon BJ et al). However, most of the ALK-positive patients progressed, particularly in the brain. During the studies with crizotinib resistance mutations were seen Second generation ALK- targeted therapies were developed, e. g. alectinib, ceritinib and brigatinib, primarily studied after progression of crizotinib. The new generation ALK-inhibitors showed significant better effect compared to standard chemotherapy and had particularly a good penetration and effect in the CNS. Alectinib was clinically compared to crizotinib as first line therapy in two large randomized studies (J-ALEX and ALEX), and both demonstrated significantly better outcome with alectinib (updated results from ALEX-study showed HR(DFS)= 0.43 with a median disease-free survival of 27.8 months versus 22.8 months for crizotinib), which was approved based on these studies for first line therapy in ALK-positive NSCLC ( Hida T et al, Shaw A et al). Brigatinib was also developed as a second-generation agent and was compared to crizotinib in the ALTA-1 study as first line therapy (HR for PFS=0.49) (Camidge DR et al), but has never been compared to alectinib. Brigatinib was demonstrated to be clearly superior to crizotinib, both with regard to outcome as well as for CNS effect. A question is, however, whether brigatinib is equal or better than alectinib as first line therapy in ALK-positive patients. The third generation ALK-inhibitors have been developed represented by lorlatinib. Ongoing randomized studies have to demonstrate the relative role of lorlatinib compared to other generation ALK-inhibitors. The most important question on this stage is how to sequence the different generations ALK-inhibitors. At most places alectinib is adapted as first line therapy, but there is no clear consensus on what comes after alectinib when the patient is progressing. In the future guidance based on resistant mutation pattern might direct subsequent therapy, but mutation guided therapy for ALK-positive patients has still to be fully developed. The sequencing of different ALK-inhibitors are currently studied in the US national Cancer Institute launched ALK Masterprotocol. 1.Solomon BJ et al: N Engl J Med 2014; 371: 2167-2177 (Crizotinib) 2. Hida T et al: Lancet 2017 (Alectinib) 3. Peters S et al: N Engl J Med 2017: 377(9): 829-838 (Alectinib) 4. Camidge DR et al. J Thorac Oncol 2019: (7): 1233-1243 (Alectinib) 4. Soria JC et al: Lancet 2017; 389: 917-929 (Ceritinib) 5. Camidge DR et al. N Engl J Med 2018; (21): 2027-2039 (Brigatinib) 5. Shaw A et al: J Clin Oncol 2019: 37(16): 1370-1379 (Lorlatinib) Crizotinib, Ceritinib, Alectinib, Brigatinib, Lorlatinib

Efficacy, safety, and biomarker analysis of ensartinib in crizotinib-resistant, ALK-positive non-small-cell lung cancer: a multicentre, phase 2 trial

Ensartinib is a potent new-generation ALK inhibitor with high activity against a broad range of known crizotinib-resistant ALK mutations and CNS metastases. We aimed to assess the efficacy and safety of ensartinib in ALK-positive patients with non-small-cell lung cancer (NSCLC), in whom crizotinib therapy was unsuccessful. The associations between ensartinib efficacy and crizotinib-resistant mutations were also explored. We did a single-arm, open-label, phase 2 study at 27 centres in China. Patients were aged 18 years or older, had stage IIIb or stage IV ALK-positive NSCLC that had progressed while they were on crizotinib therapy, an Eastern Cooperative Oncology Group performance status of 2 or less, had measurable disease, and had received fewer than three previous treatments. Patients with CNS metastases were included if these metastases were asymptomatic and did not require steroid therapy. All patients received 225 mg ensartinib orally once daily on a continuous dosing schedule. The primary outcome was the proportion of patients with an objective response according to the Response Evaluation Criteria in Solid Tumors (version 1.1), as assessed by an independent review committee in all patients who received at least one dose of ensartinib with no major violations of the inclusion criteria (ie, the full analysis set). Safety was assessed in all enrolled patients who received at least one dose of ensartinib. This trial was registered with ClinicalTrials.gov, NCT03215693. Between Sept 28, 2017, and April 11, 2018, 160 patients were enrolled and had at least one dose of ensartinib (safety analysis set). Four patients had inclusion violations and were excluded from the efficacy analysis, which thus included 156 patients (full analysis set). 97 (62%) patients in the full analysis set had brain metastases. 76 (52% [95% CI 43-60]) of 147 patients in the full analysis set, with responses that could be assessed by the independent review committee, had an objective response. 28 (70% [53-83]) of 40 patients with measurable brain metastases as assessed by the independent review committee had an intracranial objective response. 145 (91%) of 160 patients had at least one treatment-related adverse event, which were mostly grade 1 or 2. The most common treatment-related adverse events were rash (89 [56%]), increased alanine aminotransferase concentrations (74 [46%]), and increased aspartate aminotransferase concentrations (65 [41%]). Ensartinib has activity and is well tolerated in patients with crizotinib-refractory, ALK-positive NSCLC, including those with brain metastases. The role of ensartinib in patients in whom other second-generation ALK inhibitors have been unsuccessful warrants further studies. Betta Pharmaceuticals.

P2.14-69 Lorlatinib Rescue Therapy for Life Threatening CNS Disease in Crizotinib-Resistant ROS1-Positive Non–Small Cell Lung Cancer (NSCLC)

C-ros proto-oncogene-1 (ROS1) chromosomal translocations result in constitutively activated receptor tyrosine kinase in 1-2% of NSCLC. Although crizotinib, a first-generation Tyrosine Kinase Inhibitor (TKI) of Anaplastic Lymphoma Kinase (ALK) and ROS1 translocations, has demonstrated efficacy in treatment of ROS1 NSCLC, patients invariably acquire resistance mutations, with a high incidence of brain metastasis at relapse owing to poor CNS drug penetration. Lorlatinib is a novel, third-generation TKI with improved CNS penetration and preclinical activity against crizotinib-resistance mutations, which recently demonstrated efficacy in a phase I/II trial. We report a patient who developed secondary crizotinib-resistance and was successfully treated with lorlatinib. A 73-year-old, female, never-smoker with recently diagnosed stage-IV ROS1-rearranged NSCLC presented with refractory seizures and coma. The patient was on first-line treatment with crizotinib for 6-months, with an excellent systemic response at 2 months. Brain MRI after presentation demonstrated multiple intracranial metastasis with vasogenic edema (Fig.1A). Neurologic status was unchanged despite mannitol, steroids and anti-epileptics. As salvage therapy, the patient received bevacizumab for vasogenic edema and lorlatinib (100mg/daily). After 48-hours, substantial clinical improvement in neurologic function and mental status was observed. A repeat MRI (D+4) demonstrated a slight interval decrease in the largest metastasis and associated edema. At 1-month follow-up, the patient continued to improve clinically with no evidence of lorlatinib toxicity. Brain MRI showed a decrease in the sizes and/or resolution of all previously noted lesions and no new metastases or significant peritumoral edema (Fig.1B). Since clinical trials typically exclude patients with symptomatic, untreated CNS disease, efficacy of newer, targeted agents in mutated-NSCLC is unclear. Here we report on a patient with life threatening, acute neurologic deterioration who derived a meaningful clinical reduction in CNS lesions at 1 month, with favorable CNS response at 2 months. In addition, we observed early evidence of tumor regression on MRI after 4 days of lorlatinib therapy. Of note, her rapid clinical response may have in part been attributable to the addition of bevacizumab. Another important consideration for our patient is that she avoided whole-brain radiation in the acute setting, and its potential adverse sequalae. We note a limitation was the absence of available testing for secondary resistance mutations that developed in this patient, which was highly susceptible to lorlatinib. However, current clinical guidelines (NCCN) do not specifically recommend resistance mutation testing upon progression, and outside of a clinical trial, the current algorithm supports lorlatinib as the agent of choice post-crizotinib failure.

Discovery of 2-aminopyridines bearing a pyridone moiety as potent ALK inhibitors to overcome the crizotinib-resistant mutants

Despite the initial benefit demonstrated in clinical setting with ALK inhibitors, the challenging resistant mutants (F1174L, L1196M and G1202R) invariably developed. In this work, a series of 2-aminopyridine derivatives were designed and synthesized by C-5 position incorporation of a 2-pyridone moiety and bioisosteric replacement of the C-3 position linkers. Optimization of the 2-aminopyridine derivatives led to the identification of hit 18d displaying a significant growth inhibition against a variety of ALK-addicted cancer cells. Especially in the case of ALK-positive Karpas-299 cell, 18d exhibited excellent anti-proliferative potency with an IC50 value of about 40 nM. Moreover, 18d demonstrated encouraging activities against wild-type ALK (19 nM), ROS1 (2.3 nM) as well as challenging crizotinib-resistant ALKL1196M and ALKG1202R mutants with IC50 values of 45 nM and 22 nM, respectively. Additionally flow cytometric analysis indicates that 18d inhibited Karpas-299 cell viability via G1 phase arrest. Taken together, this work provided a promising ALK inhibitor to circumvent the clinical crizotinib-resistant mutants.

The new-generation selective ROS1/NTRK inhibitor DS-6051b overcomes crizotinib resistant ROS1-G2032R mutation in preclinical models

ROS1 gene rearrangement was observed in around 1–2 % of NSCLC patients and in several other cancers such as cholangiocarcinoma, glioblastoma, or colorectal cancer. Crizotinib, an ALK/ROS1/MET inhibitor, is highly effective against ROS1-rearranged lung cancer and is used in clinic. However, crizotinib resistance is an emerging issue, and several resistance mechanisms, such as secondary kinase-domain mutations (e.g., ROS1-G2032R) have been identified in crizotinib-refractory patients. Here we characterize a new selective ROS1/NTRK inhibitor, DS-6051b, in preclinical models of ROS1- or NTRK-rearranged cancers. DS-6051b induces dramatic growth inhibition of both wild type and G2032R mutant ROS1–rearranged cancers or NTRK-rearranged cancers in vitro and in vivo. Here we report that DS-6051b is effective in treating ROS1- or NTRK-rearranged cancer in preclinical models, including crizotinib-resistant ROS1 positive cancer with secondary kinase domain mutations especially G2032R mutation which is highly resistant to crizotinib as well as lorlatinib and entrectinib, next generation ROS1 inhibitors.

Design, synthesis and biological evaluations of 2-amino-4-(1-piperidine) pyridine derivatives as novel anti crizotinib-resistant ALK/ROS1 dual inhibitors

ALK and ROS1 kinases have become promising therapeutic targets since Crizotinib was used to treat non-small-cell lung cancer clinically. Aiming to explore new potent inhibitors, a series of 2-amino-4-(1-piperidine) pyridine derivatives that stabilized a novel DFG-shifted conformation in the kinase domain of ALK were designed and synthesized on the base of lead compound A. Biological evaluation highlighted that most of these new compounds could also potently inhibit ROS1 kinase, leading to the promising inhibitors against both ROS1 and ALK. Among them, the representative compound 2e stood out potent anti-proliferative activity against ALK-addicted H3122 and ROS1-addicted HCC78 cell lines (IC50 = 6.27 μM and 10.71 μM, respectively), which were comparable to that of Crizotinib. Moreover, 2e showed impressive enzyme activity against clinically Crizotinib-resistant ALKL1196M with an IC50 value of 41.3 nM, which was about 2-fold more potent than that of Crizotinib. 2e also showed potent inhibitory activity in about 6-fold superior to Crizotinib (IC50: 104.7 nM vs. 643.5 nM) in Ba/F3 cell line harboring ROS1G2032R. Furthermore, molecular modeling disclosed that all the representative inhibitors could dock into the active site of ALK and ROS1, which gave a probable explanation of anti Crizotinib-resistant mutants. These results indicated that our work has established a path forward for the generation of anti Crizotinib-resistant ALK/ROS1 dual inhibitors.

Brigatinib: Novel ALK Inhibitor for Non-Small-Cell Lung Cancer.

We review here the pharmacology, pharmacokinetics, efficacy, safety, dosage and administration, potential drug-drug interactions and place in therapy of brigatinib for abnormal anaplastic lymphoma kinase (ALK) specific non-small-cell lung cancer (NSCLC). A literature search using PubMed was conducted using the terms brigatinib and ALK positive NSCLC from January 2013 to November 2018. All English-language articles evaluating brigatinib were analyzed for this review. Brigatinib was granted approval for the treatment of patients with metastatic ALK+ NSCLC who have progressed on or are intolerant to crizotinib. It is administered at a dose of 90 mg orally once daily for the first 7 days then, if tolerated, increased to a dose of 180 mg orally once daily. Common adverse effects include nausea, fatigue, diarrhea, increased creatine phosphokinase levels, headache, dyspnea, and hypertension. Serious treatment-emergent adverse effects were pulmonary related. Relevance to Patient Care and Clinical Practice: This article discusses the clinical trials that led to the accelerated approval of brigatinib for its ability to overcome crizotinib-resistant mutations and for its increased central nervous system penetration properties. Brigatinib was granted accelerated approval for the treatment of patients with metastatic ALK+ NSCLC who have progressed on or are intolerant to crizotinib. In a subset of NSCLC patients, brigatinib increases survival for approximately 1 year; however, side effects were detected.

Abstract LB-095: Type II tyrosine kinase inhibitors overcome novel acquired crizotinib-resistant MET mutations identified in gastric cancer patient

Abstract Crizotinib, a highly selected type I MET and ALK inhibitor, has been used to counter MET amplification in different human malignancies including gastric cancer. However, transient response was observed in some patients with rapidly acquired resistant mutations on MET, such as D1228N and Y1230H. Cabozantinib and foretinib are type II tyrosine kinase inhibitors (TKIs) against MET, VEGFR2, RET, and other tyrosine kinases, which have been actively tested for treating metastatic cancers in multiple clinical trials. Here, we identified four novel crizotinib-resistant MET mutations, V1092L, G1163R, D1228G, and D1228Y in a MET-amplified gastric cancer patient progressed on crozotinib treatment. Drug responses and the impacts on downstream signaling pathways to type I and type II MET TKIs were characterized in Ba/F3 and 293T cells expressing the wild-type (WT) TPR-MET and the four MET mutants, respectively, as well as D1228N and Y1230H as positive controls for crizotinib-resistance. In consistence with the clinical observations, Ba/F3 cells carrying these mutants were all resistant to crizotinib with significantly increased IC50 compared to WT TPR-MET, although with different extend as V1092L and D1228G were less potent for crizotinib-resistance. These mutants showed similar responses to the two type II TKIs, but with various sensitivities among different mutants. Specifically, V1092L was super-sensitive to cabozantinib and foretinib with 21 folds and 9.5 folds decrease in IC50, respectively, compared to WT TPR-MET, while G1163R showed resistance to these two drugs. Interestingly, D1228Y and D1228N demonstrated moderate resistance to cabozantinib and foretinib, while D1228G showed similar sensitivity compared to WT TPR-MET, which may due to the different amino acid substitutions. Y1230H was also sensitive to these type II TKIs. We further examined the impacts of these TKIs on the three key downstream signaling pathways of MET, MAPK/ERK, PI3K/AKT, and JAK/STAT pathways in 293T cells transiently expressing all these mutants and WT control. Crizotinib significantly inhibited MAPK/ERK pathway activation in WT TPR-MET expressing cells, while all the mutants were resistant to its inhibition. Cabozantinib did not influence the MAPK/ERK and PI3K/AKT pathways for WT TPR-MET, but inhibited downstream STAT3 phosphorylation. In line with the drug response assay, V1092L and D1228G showed significant inhibition in the MAPK/ERK pathway, while G1163R, D1228Y and D1228N presented resistance to cabozantinib. However, none of the downstream signaling pathways were altered upon cabozantinib treatment for Y1230H. In conclusion, we explored the efficacy of type II TKIs cabozantinib and foretinib on crizotinib-resistant MET mutants identified in a gastric cancer patient, which showed various sensitivity to these drugs. Our study suggests that patient with MET V1092L, D1228G and Y1230H could potentially benefit from type II TKI treatment, but not for the G1163R and D1228Y/N mutations. Citation Format: Ruping Wang, Yan Ding, Xue Wu, Xiaonan Wang, Yang W. Shao. Type II tyrosine kinase inhibitors overcome novel acquired crizotinib-resistant MET mutations identified in gastric cancer patient [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-095.

3D culture system containing gellan gum restores oncogene dependence in ROS1 rearrangements non-small cell lung cancer

The ROS1 fusion gene has been identified in approximately 1% of non-small cell lung cancer (NSCLC) cases. Several clinical studies have highlighted ROS1 as a promising therapeutic target because crizotinib, a multi-targeted drug against ROS1, ALK, and the MET proto-oncogene, has elicited remarkable responses in ROS1-rearrangements NSCLC. However, acquired resistance mediated by ROS1 kinase domain mutations has been identified and a system to assess ROS1 inhibitors for these resistant mutations is necessary for the promotion of drug development. Publicly available NSCLC cell lines harboring the ROS1 fusion gene are limited to only HCC78 cells carrying SLC34A2-ROS1. This cell line exhibits resistance to ROS1 inhibitors through activation of the EGFR pathway, although the cells were established from ROS1-TKI naïve pleural effusion. Here, we demonstrate that 3D culture with gellan gum can restore the ROS1 oncogene dependence of HCC78 cells by upregulating the expression of the ROS1 fusion gene and reducing the activity of the EGFR pathway. Moreover, we established the HCC78xe3 cell line, a subclone of the HCC78 cell line, by repeated in vitro cultures from tumor xenografts and created xenograft tumors three times using in vitro cultured cells. This eventually enabled us to engraft and stably grow the cells in vivo, and subsequently evaluate various ROS1 inhibitors against HCC78xe3 cells by overexpressing crizotinib-resistant mutations in the ROS1 kinase domain including G2032R and D2033 N. We newly found that lorlatinib, a next generation ROS1/ALK inhibitor, remain the activity against D2033 N mutation. Furthermore, we demonstrated that HCC78xe3 cells expressing SLC34A2-ROS1 G2032R, and D2033 N, but not wild type (WT) cells, were resistant to crizotinib in vivo. Taken together, our data suggested that 3D cultures of HCC78 might reflect the features in patients and this new system will be a useful tool for evaluating ROS1 inhibitors.

Brigatinib for treatment of anaplastic lymphoma kinase-rearranged metastatic non-small cell lung cancer

ABSTRACTIntroduction: Crizotinib has been approved as a first-line treatment for patients with anaplastic lymphoma kinase (ALK)-rearranged advanced non-small-cell lung cancer (NSCLC). However, the majority of patients treated with crizotinib experience progression within 1 year, and the central nervous system (CNS) is the most common site of progression. Brigatinib, a potent and selective ALK inhibitor that can inhibit multiple crizotinib-resistant ALK mutants, has shown superior efficacy in advanced ALK-rearranged NSCLC, including in patients with CNS metastases.Areas covered: We reviewed the characteristics of brigatinib, and its clinical efficacy and safety have been demonstrated in previous pivotal studies.Expert opinion: Brigatinb was recently approved for use in ALK-rearranged NSCLC with acquired resistance to crizotinib as first-line treatment. Moreover, brigatinib is highly active in patients with CNS metastasis. The major concern about pulmonary adverse events was resolved with changes in treatment schedule. The mechanisms of resistance to brigatinib and the sequence of treatment with other ALK inhibitors are unresolved issues.

An UPLC–MS/MS method to determine CT-707 and its two metabolites in plasma of ALK-positive advanced non-small cell lung cancer patients

CT-707, a mutant-selective inhibitor of an important cancer target, anaplastic lymphoma kinase (ALK), is designed to be a targeted therapeutic agent for non-small cell lung cancer (NSCLC) patients harboring ALK active and crizotinib resistant mutations. A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS) method was developed and validated for the determination of CT-707 and its two metabolites (M1 and M2) in human plasma. The samples were purified by solid phase extraction (SPE) and separated on a BEH C18 column (2.1 × 50 mm, 1.7 μm). Electrospray ionization (ESI) in positive ion mode and multiple reactions monitoring (MRM) were used to monitor the ion transitions at m/z 636.4+ → 413.3+, 594.4+ → 494.4+, 622.5+ → 536.4+, respectively. The results indicated that the method had excellent sensitivity and selectivity. The linear range covered from 2 to 500 ng/mL for CT-707and from 1 to 100 ng/mL for M1 and M2. Intra-run and inter-run precisions (in terms of %RSD) were all <15% and the accuracies (in terms of %RE) were within the range of ±15%. The lower limit of quantification (LLOQ), matrix effect, extraction recovery, stability, dilution test and carryover test were also validated and satisfied with the criteria of validation. Finally, the method was successfully applied to a phase I clinical study of ALK-positive advanced NSCLC patients after an oral administration of CT-707.

Abstract B185: TPX-0005, a supreme ROS1 inhibitor, overcomes crizotinib-resistant ROS1 mutations including solvent front mutation G2032R and gatekeeper mutation L2026M

Abstract The fusion kinases of ROS1 and ALK have been identified as oncogene drivers in small portions of many malignancies, especially in non-small cell lung cancer (NSCLC). ALK/ROS1/MET inhibitor crizotinib has been approved by the US Food and Drug Administration for the treatment of ALK or ROS1-positive non-small cell lung cancer in 2011 and 2016, respectively. The emergence of drug resistance presents a major issue for targeted therapy. Although ceritinib, alectinib, and brigatinib have been approved for crizotinib-refractory ALK+ patients with NSCLC, treatment options for patients with ROS1+ NSCLC are limited, especially for crizotinib-refractory patients. Ceritinib and entectinib demonstrated clinical efficacy only in crizotinib-naïve ROS1+ patients. The most common resistance mechanisms to crizotinib treatment in ROS1+ NSCLC is the solvent front mutation ROS1 G2032R and gatekeeper mutation ROS1 L2026M. TPX-0005, a novel three-dimensional macrocycle with a much smaller size than current ROS1 inhibitors in the clinic, was designed to overcome clinical resistance mutations systematically. TPX-0005 potently inhibited both wild type and mutant ROS1s including solvent front mutations and gatekeeper mutations. TPX-0005 showed pico-molar activity against ROS1 kinase (IC50 0.076 nM) in Reaction Biology kinase assay. The comparison of TPX-0005 with other ROS1 inhibitors in Ba/F3 cell proliferation assays is presented in the table. In the xenograft tumor model studies, TPX-0005 dramatically caused tumor regression in the tumors carrying WT or solvent-front mutated ROS1 fusion gene. Overall, TPX-0005 demonstrated desired drug-like properties, good safety profile, and is a supreme ROS1 inhibitor against WT and various mutated ROS1s. A phase 1/2 clinical trial of TPX-0005 is actively being pursued (NCT03093116). CD74-ROS1 Ba/F3 Cell Proliferation Assay IC50 (nM)InhibitorWTG2032RD2033NL2026MS1986FS1986YTPX-0005&amp;lt;0.28.40.210&amp;lt;0.2&amp;lt;0.2Crizotinib9.71402139606.420.919Lorlatinib0.5262.42.4ND0.30.3Entrectinib25.42404ND2026NDNDCeritinib131.92000NDND14.226.9Brigatinib28.61385167.1211527.724.6Cabozantinib1.060.70.129.1NDND ND: not determined. Citation Format: J. Jean Cui, Dayong Zhai, Wei Deng, Evan Rogers, Zhongdong Huang, Jeffrey Whitten, John Lim, Yishan Li. TPX-0005, a supreme ROS1 inhibitor, overcomes crizotinib-resistant ROS1 mutations including solvent front mutation G2032R and gatekeeper mutation L2026M [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B185.

Discovery of novel 2,4-diarylaminopyrimidine analogues as ALK and ROS1 dual inhibitors to overcome crizotinib-resistant mutants including G1202R

Aiming to explore novel anaplastic lymphoma kinase (ALK) and proto-oncogene tyrosine-protein kinase ROS (ROS1) dual inhibitors to overcome crizotinib-resistant mutants, two series of 2,4-diarylaminopyrimidine (DAAP) analogues bearing thiazole or 1,2,3-triazole moieties were designed and synthesized based upon the cocrystal structure of ceritinib with ALKWT (PDB 4MKC) as well as the binding model of ceritinib with ALKG1202R. The cellular and enzymatic assays validated 34c (WY-135) as a promising ALK (IC50 = 1.4 nM) and ROS1 (IC50 = 1.1 nM) dual inhibitor superior to crizotinib and ceritinib. 34c showed significantly inhibitory activities on ALK-dependent cell lines KARPAS299 (IC50 = 21 nM) and H2228 (IC50 = 95 nM) as well as ROS1-positive cell line HCC78 (IC50 = 40 nM). In particular, 34c was potent against a variety of frequently observed crizotinib-resistant mutants, particularly the L1196M mutant (IC50 = 3.1 nM) identified as the “gatekeeper” mutation and the G1202R mutant (IC50 = 8.7 nM) which conferred resistance to all clinical stage ALK inhibitors. Furthermore, 34c was capable of inducing cell apoptosis and strongly inhibiting cellular ALK and ROS1 activity. In addition, the binding models of 34c with ALKWT, ALKL1196M and ALKG1202R provided structural bases for SARs observations.