ROS1 Inhibitor Research Articles

1548P - Crizotinib in patients with advanced or metastatic ROS1-rearranged lung cancer (EUCROSS): A European phase II clinical trial – Updated progression-free survival, overall survival and mechanisms of resistance

BackgroundROS1 fusions are found in 1% of lung cancer patients. EUCROSS is the first prospective European trial to evaluate crizotinib in this patient subset. Here we present an updated analysis of the progression-free survival (PFS), overall survival (OS) and molecular characteristics of progression. MethodsMulti-centre, single arm phase II trial. Key eligibility criteria: ≥18 years of age, advanced/metastatic lung cancer, centrally confirmed ROS1-rearrangement. Treatment: 250mg crizotinib BID. Key endpoints of this report: updated PFS (according to RECIST 1.1) and OS and molecular tumour characterization. ResultsThirty patients were eligible for response evaluation (N=30; intention-to-treat population, N=34). Median follow-up was 44.9 months (95% CI, 39.6-47.4). At data-cut off 19 patients (63.3%) discontinued treatment due to progression or death. Investigator-assessed efficacy: ORR, 70% (95% CI, 51–85; 21/30); disease control rate, 90.0% (95% CI, 73.5-97.9; 27/30); median PFS, 19.4 months (95% CI, 10.1-31.2); 24-months-OS probability, 65.5% (95% CI, 48.3-82.9). Prevalence of co-occurring genetic aberrations by hybrid-capture sequencing was 61%. TP53 mutations were most frequent (28%; 5/18). PFS (p=0.0219) and OS at 24 months (p=0.015) were significantly shorter in TP53-mutant patients. Tissue or blood samples were collected in six patients at progression. In three (50%) samples, secondary mutations in ROS1 (i.e. p.G2032R (N=2), p.L2026M (N=1)) were detected. In one (17%), a PIK3CA mutation (p.E545K) was identified. In the other two patients (33%) aberrations of unknown significance were detected. ConclusionsUpdated PFS and OS results confirm the efficacy of crizotinib in ROS1-rearranged lung cancer patients. Patients with co-mutations in TP53 had significantly worse outcomes compared to TP53 wild-type patients. The most common mechanisms of resistance were mutations in ROS1. Next-generation ROS1 inhibitors or the multi-kinase inhibitor cabozantinib may be promising treatment options for these patients. Clinical trial identificationNCT02183870. Legal entity responsible for the studyUniversity Hospital of Cologne. FundingPfizer. DisclosureS. Michels: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Pfizer; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Bristol-Myers Squibb; Honoraria (self): Boehringer Ingelheim; Research grant / Funding (institution): Janssen; Honoraria (self): Roche. B. Massuti Sureda: Honoraria (self): Merck Sharp Dome; Honoraria (self): Boehringer Ingelheim; Honoraria (self): Roche; Honoraria (self): Pfizer. H. Schildhaus: Honoraria (self): ZytoVision; Honoraria (self): Pfizer; Honoraria (self), Research grant / Funding (institution): Roche; Honoraria (self), Research grant / Funding (institution): Novartis. M. Sebastian: Honoraria (self): Boehringer Ingelheim; Honoraria (self): Eli Lilly; Honoraria (self): Pfizer; Honoraria (self): Roche; Honoraria (self): Novartis; Honoraria (self): AstraZeneca; Honoraria (self): Bristol-Myers Squibb; Honoraria (self): Merck Sharp Dome; Honoraria (self): Takeda; Honoraria (self): Mediolanum; Honoraria (self): AbbVie; Honoraria (self): Celgene. E. Felip: Honoraria (self): AstraZeneca; Honoraria (self): Boehringer Ingelheim; Honoraria (self): Bristol-Myers Squibb; Honoraria (self): Celgene; Honoraria (self): Eli Lilly; Honoraria (self): Guardiant; Honoraria (self): Merck Sharp Dome; Honoraria (self): Merck KGa; Honoraria (self): Novartis. M. Reck: Honoraria (self): Boehringer Ingelheim; Honoraria (self): Bristol-Myers Squibb; Honoraria (self): AstraZeneca; Honoraria (self): Abbot; Honoraria (self): Celgene; Honoraria (self): Merck Sharp Dome; Honoraria (self): Merck KGa; Honoraria (self): Novartis; Honoraria (self): Pfizer; Honoraria (self): Roche. S. Merkelbach-Bruse: Honoraria (self): Pfizer; Honoraria (self): AstraZeneca; Honoraria (self): Bristol-Myers Squibb; Honoraria (self): Roche; Honoraria (self), Research grant / Funding (institution): Novartis. L. Nogova: Honoraria (self), Research grant / Funding (institution): Pfizer; Honoraria (self), Research grant / Funding (institution): Novartis; Honoraria (self), Research grant / Funding (institution): Janssen; Honoraria (self): Boehringer Ingelheim; Honoraria (self): Roche; Honoraria (self): Celgene. J. Wolf: Honoraria (self), Research grant / Funding (institution): Novartis; Honoraria (self), Research grant / Funding (institution): Pfizer; Honoraria (self), Research grant / Funding (institution): Janssen; Honoraria (self): Boehringer Ingelheim; Honoraria (self): AstraZeneca; Honoraria (self), Research grant / Funding (institution): Bristol-Myers Squibb; Honoraria (self): Chugay; Honoraria (self): Ignyta; Honoraria (self): Eli Lilly; Honoraria (self): Merck Sharp Dome; Honoraria (self): Roche. All other authors have declared no conflicts of interest.

Profile of entrectinib and its potential in the treatment of ROS1-positive NSCLC: evidence to date.

ROS1 inhibition provides impressive survival benefits in ROS1-rearranged non-small cell lung cancer (NSCLC) patients. Crizotinib is the only tyrosine kinase inhibitor (TKI) approved by both FDA and EMA for the treatment of ROS1-positive lung cancer. In addition, several TKI have been tested with preliminary proofs of success in this oncogene-driven disease, either in the post-crizotinib setting or as first-line targeted agents. Here we present the evidence concerning entrectinib, an ALK/ROS1/NTRK inhibitor developed across different tumor types harboring rearrangements in these genes, in the context of ROS1-driven NSCLC. Of interest, in August 2019 entrectinib was granted by FDA accelerated approval for the treatment of ROS1-rearranged NSCLC, as well as of NTRK-driven solid tumors.

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.

Abstract 1319: Repotrectinib, a new generation ROS1 inhibitor, is highly potent against fusion ROS1s and emerging resistance mutations

Abstract Chromosome rearrangements of ROS1 have been identified as oncogenic drivers in many malignancies, especially non-small cell lung cancer (NSCLC). Crizotinib is the only approved treatment for ROS1+ NSCLC. The efficacy of crizotinib varies among different types of ROS1 fusion partners in patients with ROS1-rearranged NSCLC, and the most dominant fusion CD74-ROS1 was associated with a higher rate of brain metastases and shorter overall survival. Unfortunately, the emergence of drug resistance to crizotinib and other ROS1-targeted therapies represents a major obstacle. The most common resistance mutations to crizotinib in ROS1+ NSCLC are the solvent front mutation (SFM) ROS1 G2032R and gatekeeper mutation ROS1 L2026M. Repotrectinib was rationally designed to overcome resistance mutations. The activity of repotrectinib against multiple fusion ROS1s and corresponding resistance mutations is outlined in the Table. Repotrectinib potently inhibited both wildtype and mutated fusion ROS1s including SFMs and gatekeeper mutations. In cell growth assays using engineered Ba/F3 cells expressing ROS1 fusions with several different partners, such as SDC4, CD74, TPM3 and EZR, repotrectinib demonstrated superior potency in comparison to other ROS1 inhibitors against multiple ROS1 mutations, especially the solvent front and gatekeeper mutations. In xenograft tumor model studies, repotrectinib resulted in tumor regression in the tumors carrying WT or SFM ROS1 fusion genes. Overall, repotrectinib demonstrated a strong inhibition profile against WT and various mutated ROS1s across different fusion partners when compared to many other ROS1 TKIs. A Phase 1/2 clinical trial of repotrectinib is currently enrolling ROS1+ NSCLC patients (NCT03093116). Ba/F3 Cell Proliferation IC50 (nM)No Kinase Domain MutationROS1 G2032RROS1 L2026MInhibitorCD74-ROS1SDC4-ROS1EZR-ROS1TPM3-ROS1CD74-ROS1SDC4-ROS1EZR-ROS1TPM3-ROS1EZR-ROS1TPM3-ROS1Repotrectinib<0.20.2<0.1<0.13.33516.3<0.2<0.1Crizotinib14.619.619.431.1266.24661660500.695.6236.2Lorlatinib0.20.30.20.3160.7352.9190.5434.91.61.9Entrectinib10.5ND1.59.41813ND2947109313.340.7Ceritinib42.859.833.110513911883885.8543.712.666.5Brigatinib2138.725.86111721473360.6300024.441.3Cabozantinib0.530.44.511.3169.439.560.73.412.6Ensartinib39.5ND118.6433.1371.8ND17574814543.31463 Citation Format: Wei Deng, Dayong Zhai, Xin Zhang, Dong Lee, Evan Rogers, Jeffrey Whitten, J. Jean Cui. Repotrectinib, a new generation ROS1 inhibitor, is highly potent against fusion ROS1s and emerging resistance mutations [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 1319.

Abstract 2122: Generation of a fully characterized preclinical PDX panel to accelerate the identification of next generation treatments for patients with acquired resistance to targeted therapies

Abstract The last 20 years have witnessed the identification of an increasing number of actionable oncogenic drivers and the development and clinical use of specific inhibitors against these targets. Unfortunately, patients treated with targeted therapies consistently develop resistance and progression under treatment. Hence, important scientific, pharmaceutical and medical research efforts are directed towards understanding the mechanisms of acquired resistance to explore new therapeutic pathways. The MATCH-R clinical trial enrolls patients with oncogene-driven cancer who have had previous clinical response to targeted therapy and subsequently experienced disease progression. In the framework of this project, Gustave Roussy and XenTech are joining forces to develop a panel of patient-derived xenografts (PDXs) derived from biopsies collected from these patients at the stage of acquired resistance. These PDX models will be fully characterized at molecular and pharmacological level and used to improve knowledge on the mechanisms underlying resistance to treatment and to evaluate response to new treatments. In this perspective, the development of 75 PDX-AR (Acquired Resistance) models is planned over 3 years. All the models are maintained under the same therapeutic pressure the parental tumor was submitted to at the time of biopsy, and will be subjected to extensive phenotypic and genotypic characterization. To favor successful xenograft establishment, the first two passages are performed without drug treatment, which is applied from the third passage on. When doing so, we observed 3 types of response: some models showed resistance from the first passage under treatment, some showed stabilization under treatment at the first passages and rapidly acquired resistance over passages, and others showed sensitivity to treatment, whereas the patient tumor showed progression under the same treatment. These different behaviors might be due to different mechanisms of resistance, irreversible for the former, reversible for the two latter, as well as to suboptimal correlation of the clinical dose with the one used in mice. An example of such discrepancies has been found in two models of NSCLC PDX obtained from two metastases from a patient treated by a ROS1 and ALK inhibitor. While LCx-MR135PD2-AR PDX does not respond to the treatment, the LCx-MR135PD1 model is highly sensitive. As both metastases were progressing under treatment in the patient, molecular and pharmacological comparative analysis of these two models will investigate these discrepancy and provide important insights into the mechanisms of resistance to such inhibitors. Overall, the MatchR PDX project will provide a unique preclinical platform to identify resistance mechanisms to current targeted therapies and to develop next generation therapeutic strategies. Citation Format: Olivier Déas, Ludovic Bigot, Emilie Dasse, Guillaume Lang, Yohann Loriot, Fabrice Andre, Jean-Charles Soria, Benjamin Besse, Stefano Cairo, Marie Tavernier, Katell Mevel, Enora Le Ven, Jean-Gabriel Judde, Luc Friboulet. Generation of a fully characterized preclinical PDX panel to accelerate the identification of next generation treatments for patients with acquired resistance to targeted therapies [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 2122.

Abstract CT192: 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 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-naïve 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-naïve, 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, Jürgen 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.

Abstract 1317: Exceptional responses to crizotinib in breast cancer patients with somatic MET and ROS1 alterations

Abstract Crizotinib is FDA approved in lung cancers with alterations in MET, ROS1 or ALK. Alterations in these genes are also reported in breast cancer, but are very rare and not routinely evaluated. Here we describe two heavily pre-treated patients with metastatic breast cancer treated with off-label single-agent crizotinib following NGS panel detection of alterations in MET and ROS1 in their tumors. Both patients had strong responses to crizotinib. Patient I was a stage IV triple-negative breast cancer patient in her early forties, previously treated with doxorubicin/cyclophosphamide, carboplatin/paclitaxel and with capecitabine. PET/CT imaging after progression on capecitabine revealed extensive metastatic disease. A NGS assay detected a 30-fold amplification of MET. MET amplification, overexpression and hyperactivity was confirmed by FISH and by IHC for total MET and phospho-MET, respectively. Single agent crizotinib (250 mg, twice daily) was well-tolerated. Immunostaining of a biopsy taken after 9 days of treatment showed elimination of active phosphorylated MET, demonstrating in-tumor crizotinib efficacy at the clinical dose. CT imaging at 10 weeks showed a resolution of her metastatic disease, meeting RECIST 1.1 criteria for a complete response. This response was sustained at 22 weeks. At 37 weeks, the patient progressed in the pleura. An ultrasound guided biopsy revealed a robust resurgence of MET phosphorylation while still taking crizotinib, suggesting an alteration rendering MET recalcitrant to crizotinib. NGS revealed a MET D1228N mutation, previously reported in crizotinib resistant lung cancer. This mutation was not detected in the pre-crizotinib biopsy (locus sequenced at 6300x) suggesting de novo acquisition in response to crizotinib. Mechanistic studies in HEK393 cells indicated that this mutation is sufficient to confer crizotinib (Type I MET inhibitor) resistance but remains sensitive to cabozantinib (Type II MET inhibitor). Transition to cabozantinib (initially 60 mg/day, later 100 mg/day) resulted in clinically stable disease for a period of 7 weeks, at which point the patient again progressed. Patient II had ER+ PR+ HER2- breast cancer in 2014 and developed metastatic disease in 2017. She was subsequently treated with fulvestrant/palbociclib before an NGS panel revealed a GOPC-ROS1 fusion. She had a brisk response to crizotinib, documented by both imaging and reduction in circulating CA27-29. After experiencing crizotinib-related pneumonitis, she switched to ceritinib (an alternative ROS1 inhibitor) and continues to have an excellent response following six months of anti-ROS1 treatment. Together, these cases underline the value of NGS panel sequencing in patients with metastatic breast cancer. Although alterations in crizotinib-sensitive pathways are quite rare in breast cancer, very substantial clinical responses may be observed if these patients can be identified. Citation Format: Benjamin M. Parsons, David R. Meier, Sreeja Sreekumar, Craig S. Richmond, Kyle J. Ernzen, Kristopher A. Lofgren, Jake A. Deviley, Grzegorz T. Gurda, Paraic A. Kenny. Exceptional responses to crizotinib in breast cancer patients with somatic MET and ROS1 alterations [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 1317.

Resistance mechanisms and potent-targeted therapies of ROS1-positive lung cancer.

The discovery of targetable mutations, which cause gene rearrangement, led to a major advancement in the treatment of patients with non-small cell lung cancer (NSCLC), and cancers with such mutations can be paired with drugs which specifically target them. c-ros oncogene (ROS1) positive NSCLC is one molecular subtype of NSCLC with a therapeutic target. Currently, different targeted therapies and ROS1 inhibitors have been discovered, but all are in different investigational phases, with only one (crizotinib) which is FDA approved. Crizotinib is a small-molecule tyrosine kinase inhibitor (TKI) which was discovered to actively inhibit ALK, MET, and ROS1. Crizotinib has shown to be remarkably efficacious against ROS1 lung cancer, prompting ROS1 detection in lung cancer to be quite significant. Sadly, crizotinib resistance in ROS1 is a frequent occurrence which poses a major clinical challenge in the successful treatment of ROS1 lung cancer; hence, the discovery of the second and third generation ROS1 inhibitors is of utmost importance. In this review, we discuss the underlying mechanisms through which ROS1 tumor cells acquire resistance to crizotinib-the first-line drug for ROS1-positive NSCLC, and summarize various new potent drugs which can overcome this resistance and serve as viable alternatives.

ALK, ROS1 and EGFR next-generation tyrosine kinase inhibitors in advanced non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) is the most common cancer in men and the second most common in fe- males. In previous years the significance of some molecular disorders in pathogenesis NSCLC was proven and the value of targeted therapies in the treatment of patients was documented. In subjects with abnormalities of EGFR , ALK and ROS1 genes, appropriate tyrosine kinase inhibitors (TKIs) may be used. The use of these drugs in the first and second treatment lines has affected a significant improvement in the prognosis in this subgroup of patients. The article presents mechanisms of action and data on the clinical value of lorlatinib, brigatinib and dacomitinib in the treatment of patients with advanced lung of lung cancer.

Therapeutic implications of a novel driver classification system for cutaneous and unknown primary melanomas.

9539 Background: Cutaneous and “unknown primary” melanomas frequently harbor alterations that activate the Mitogen Activated Protein Kinase (MAPK) pathway, and are often classified as BRAF, NRAS, NF1 mutant, or “triple wild type.” Multigene sequencing may identify additional oncogenic drivers, but the clinical impact of this information is unknown. Methods: Patients with BRAF inhibitor naïve melanoma underwent prospective tumor molecular profiling using a targeted capture-based assay (MSK-IMPACT), and demographic and treatment data were collected. Time to treatment failure was assessed for patients who received frontline PD-1 monotherapy or nivolumab plus ipilimumab. Results: 576 patients were successfully sequenced. 533 samples (96%) harbored a known or presumed oncogenic mutation in 1 of 28 genes in the RTK-RAS-MAPK pathway. 187 tumors (32%) had two or more drivers in this pathway, and the rates of driver co-alterations varied widely by specific driver. A hierarchical classification of 9 driver groups (BRAF V600E; V600K/R/M; BRAF non-V600; NRAS Q61; Other RAS; NF1; KIT; Other driver; Unknown driver) was significantly associated with tumor mutational burden, primary melanoma site, and patient age. Time to treatment failure varied by driver class and site of primary melanoma for PD-1 monotherapy but not nivolumab plus ipilimumab. 150 patients with BRAF V600 wild-type melanoma required systemic therapy after progression on checkpoint blockade. 21 were given genomically matched therapy, and 5/21 had clinical benefit for ≥6 months. Complete and durable responses were observed with TRK and ROS1 inhibitors in patients with NTRK1/2/3 and ROS1 fusion positive tumors. Conclusions: Oncogenic alterations in the RTK-RAS-MAPK pathway can be detected using targeted capture NGS in the vast majority of cutaneous and unknown primary melanomas. A hierarchical classification of 9 driver groups revealed clinically relevant melanoma subsets with varying clinical outcomes to PD-1 monotherapy. Select patients with oncogenic kinase fusions can achieve durable therapeutic benefit with targeted inhibitors of these rare drivers.

109O - 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.

18F-FDG PET/CT Evaluation of Crizotinib and Lorlatinib Therapy in Metastatic ROS-1–Positive Non–Small Cell Lung Cancer

ROS-1-positive non-small cell lung cancers (NSCLCs) are rare (approximately 1% of all NSCLCs) and require a first-line treatment by crizotinib. Crizotinib resistance is frequent within the first 12 months of treatment. Lorlatinib is a novel tyrosine kinase inhibitor of ROS-1 recently indicated for metastatic or locally advanced crizotinib-resistant NSCLC. We report the use of lorlatinib as second-line with a complete tumoral response after only 3 months of treatment. This case shows the major role of F-FDG PET/CT in treatment evaluation and monitoring targeted therapy in metastatic NSCLC.

Oral coadministration of elacridar and ritonavir enhances brain accumulation and oral availability of the novel ALK/ROS1 inhibitor lorlatinib

Lorlatinib, a novel generation oral anaplastic lymphoma kinase (ALK) and ROS1 inhibitor with high membrane and blood-brain barrier permeability, recently received accelerated approval for treatment of ALK-rearranged non-small-cell lung cancer (NSCLC), and its further clinical development is ongoing. We previously found that the efflux transporter P-glycoprotein (MDR1/ABCB1) restricts lorlatinib brain accumulation and that the drug-metabolizing enzyme cytochrome P450-3A (CYP3A) limits its oral availability. Using genetically modified mouse models, we investigated the impact of targeted pharmacological inhibitors on lorlatinib pharmacokinetics and bioavailability. Upon oral administration of lorlatinib, the plasma AUC0-8h in CYP3A4-humanized mice was ∼1.8-fold lower than in wild-type and Cyp3a–/– mice. Oral coadministration of the CYP3A inhibitor ritonavir caused reversion to the AUC0-8h levels seen in wild-type and Cyp3a–/– mice, without altering the relative tissue distribution of lorlatinib. Moreover, simultaneous pharmacological inhibition of P-glycoprotein and CYP3A4 with oral elacridar and ritonavir in CYP3A4-humanized mice profoundly increased lorlatinib brain concentrations, but not its oral availability or other relative tissue distribution. Oral lorlatinib pharmacokinetics was not significantly affected by absence of the multispecific Oatp1a/1b drug uptake transporters. The absolute oral bioavailability of lorlatinib over 8 h in wild-type, Cyp3a–/–, and CYP3A4-humanized mice was 81.6%, 72.9%, and 58.5%, respectively. Lorlatinib thus has good oral bioavailability, which is markedly restricted by human CYP3A4 but not by mouse Cyp3a. Pharmacological inhibition of CYP3A4 reversed these effects, and simultaneous P-gp inhibition with elacridar boosted absolute brain levels of lorlatinib by 16-fold without obvious toxicity. These insights may help to optimize the clinical application of lorlatinib.

Identification of 1H-pyrazolo[3,4-b]pyridine derivatives as potent ALK-L1196M inhibitors

Anaplastic lymphoma kinase (ALK) has been recognised as a promising molecular target of targeted therapy for NSCLC. We performed SAR study of pyrazolo[3,4-b]pyridines to override crizotinib resistance caused by ALK-L1196M mutation and identified a novel and potent L1196M inhibitor, 10g. 10g displayed exceptional enzymatic activities (<0.5 nM of IC50) against ALK-L1196M as well as against ALK-wt. In addition, 10g is an extremely potent inhibitor of ROS1 (<0.5 nM of IC50) and displays excellent selectivity over c-Met. Moreover, 10g strongly suppresses proliferation of ALK-L1196M-Ba/F3 and H2228 cells harbouring EML4-ALK via apoptosis and the ALK signalling blockade. The results of molecular docking studies reveal that, in contrast to crizotinib, 10g engages in a favourable interaction with M1196 in the kinase domain of ALK-L1196M and hydrogen bonding with K1150 and E1210. This SAR study has provided a useful insight into the design of novel and potent inhibitors against ALK gatekeeper mutant.

Rare but Recurrent ROS1 Fusions Resulting From Chromosome 6q22 Microdeletions are Targetable Oncogenes in Glioma.

Gliomas, a genetically heterogeneous group of primary central nervous system tumors, continue to pose a significant clinical challenge. Discovery of chromosomal rearrangements involving kinase genes has enabled precision therapy, and improved outcomes in several malignancies. Positing that similar benefit could be accomplished for patients with brain cancer, we evaluated The Cancer Genome Atlas (TCGA) glioblastoma dataset. Functional validation of the oncogenic potential and inhibitory sensitivity of discovered ROS1 fusions was performed using three independent cell-based model systems, and an in vivo murine xenograft study. In silico analysis revealed previously unreported intrachromosomal 6q22 microdeletions that generate ROS1-fusions from TCGA glioblastoma dataset. ROS1 fusions in primary glioma and ependymoma were independently corroborated from MSK-IMPACT and Foundation Medicine clinical datasets. GOPC-ROS1 is a recurrent ROS1 fusion in primary central nervous system (CNS) tumors. CEP85L-ROS1 and GOPC-ROS1 are transforming oncogenes in cells of astrocytic lineage, and amenable to pharmacologic inhibition with several ROS1 inhibitors even when occurring concurrently with other cancer hotspot aberrations frequently associated with glioblastoma. Oral monotherapy with a brain-permeable ROS1 inhibitor, lorlatinib, significantly prolonged survival in an intracranially xenografted tumor model generated from a ROS1 fusion-positive glioblastoma cell line. Our findings highlight that CNS tumors should be specifically interrogated for these rare intrachromosomal 6q22 microdeletion events that generate actionable ROS1 fusions. ROS1 fusions in primary brain cancer may be amenable for clinical intervention with kinase inhibitors, and this holds the potential of novel treatment paradigms in these treatment-refractory cancer types, particularly in glioblastoma.

MTE20.02 Molecular Testing in Small Samples

Molecular targeted therapies have become a standard treatment for patients with lung cancer. Driver genetic alterations such as EGFR mutations, ALK rearrangements and ROS1 rearrangements are currently used as predictive biomarkers for EGFR tyrosine kinase inhibitors (TKIs), ALK inhibitors, and ROS1 inhibitors, respectively. In addition, antibodies blocking the PD-1 ligand PD-L1 have shown prominent antitumor activities and durable clinical response. Molecular analyses of these predictive biomarkers in tumor tissue or cytology specimens are the first prerequisite laboratory tests for the clinical management of lung cancers. Despite the increasing number of targets to be tested, most patients harboring non-small cell lung carcinoma (NSCLC) presents with advanced stage at the time of diagnosis, so the amount of tissue that can be acquired is very small. Small biopsy and cytology samples obtained from a variety of methods are acceptable for molecular testing, including transbronchial lung biopsy, endobronchial ultrasound– guided transbronchial needle aspiration, bronchial brushing or washing, computed tomography–guided gun biopsy or needle aspiration, and pleural fluid sampling. The molecular testing results using cytology samples are highly concordant with those of the corresponding tissue samples, especially with more sensitive methods. Routinely prepared cytology samples such as alcohol-fixed smears or cell block samples are also suitable for mutation testing. As targetable genetic alterations are increasingly identified, individual genotyping or molecular test seemed to be relatively inefficient and expensive. Thus, next-generation sequencing (NGS) technology with DNA or RNA is reported to be useful method for multiplexed and deep targeted sequencing. In this situation, each pathology laboratory needs to make a strategic approach to use these small samples in considerations of the important priorities for the management of the patients. In this MET session, I will introduce our experience of strategic approach to obtain the most useful information while reducing the loss of tissue using a small amount of samples. 1. Li T, Kung HJ, Mack PC, Gandara DR. Genotyping and genomic profiling of non-small-cell lung cancer: implications for current and future therapies. J Clin Oncol 2013; 31: 1039-49. 2. Brahmer JR, Tykodi SS, Chow LQ et al. Safety and Activity of Anti-Pd-L1 Antibody in Patients with Advanced Cancer. N Engl J Med 2012; 366: 2455-2465. 3. Shim HS, Choi YL, Kim L, et al. Molecular testing of lung cancers J Pathol Trans Med 2017; 51: 242-254.. 4. Sun PL, Jin Y, Kim H, Lee CT, Jheon S, Chung JH. High concordance of EGFR mutation status between histologic and corresponding cytologic specimens of lung adenocarcinomas. Cancer Cytopathol 2013; 121: 311-9. . small samples, Lung neoplasms, molecular testing

Entrectinib and other ALK/TRK inhibitors for the treatment of neuroblastoma.

RTK plays important roles in many cellular signaling processes involved in cancer growth and development. ALK, TRKA, TRKB, TRKC, and ROS1 are RTKs involved in several canonical pathways related to oncogenesis. These proteins can be genetically altered in malignancies, leading to receptor activation and constitutive signaling through their respective downstream pathways. Neuroblastoma (NB) is the most common extracranial solid tumor in childhood, and despite intensive therapy, there is a high mortality rate in cases with a high-risk disease. Alterations of ALK and differential expression of TRK proteins are reported in a proportion of NB. Several inhibitors of ALK or TRKA/B/C have been evaluated both preclinically and clinically in the treatment of NB. These agents have had variable success and are not routinely used in the treatment of NB. Entrectinib (RXDX-101) is a pan-ALK, TRKA, TRKB, TRKC, and ROS1 inhibitor with activity against tumors with ALK, NTRK1, NTRK2, NTRK3, and ROS1 alterations in Phase I clinical trials in adults. Entrectinib’s activity against both ALK and TRK proteins suggests a possible role in NB treatment, and it is currently under investigation in both pediatric and adult oncology patients.

Dual potent ALK and ROS1 inhibitors combating drug-resistant mutants: Synthesis and biological evaluation of aminopyridine-containing diarylaminopyrimidine derivatives

To identify ALK and ROS1 dual inhibitors conferring resistance to ALK secondary mutations, especially ‘gatekeeper’ L1196 M and the most predominant ceritinib-resistant G1202R mutations, a series of novel 2,4-diarylaminopyrimidine analogues were designed and synthesized by incorporating 2-alkoxy-6-alicyclic aminopyridinyl motifs. The biological evaluations on cellular and enzymatic assays led to identification of compound F-1, which turned out to be effective against ALKWT, ROS1WT, ALKL1196M and ALKG1202R kinases with IC50 of 2.1 nM, 2.3 nM, 1.3 nM and 3.9 nM, respectively, superior to crizotinib and ceritinib. Moreover, F-1 exhibited significant cytotoxicity on ALK-addicted Karpas299, H2228, and Ba/F3 cell expressing G1202R mutant, as well as ROS1-positive HCC78 cell with IC50 values ranging from 10 nM to 43 nM. Notably, F-1 was capable of suppressing phospho-ALK and its relative downstream signaling pathways, and eventually, inducing cell apoptosis in a dose-dependent manner in Karpas-299 cell. Together, F-1 is validated as a promising ALK/ROS1 dual inhibitor great potential for G1202R ALK mutation cancers.

P-glycoprotein (MDR1/ABCB1) restricts brain accumulation and cytochrome P450-3A (CYP3A) limits oral availability of the novel ALK/ROS1 inhibitor lorlatinib.

Lorlatinib (PF-06463922) is a promising oral anaplastic lymphoma kinase (ALK) and ROS1 inhibitor currently in Phase III clinical trials for treatment of non-small-cell lung cancer (NSCLC) containing an ALK rearrangement. With therapy-resistant brain metastases a major concern in NSCLC, lorlatinib was designed to have high membrane and blood-brain barrier permeability. We investigated the roles of the multidrug efflux transporters ABCB1 and ABCG2, and the multispecific drug-metabolizing enzyme CYP3A in plasma pharmacokinetics and tissue distribution of lorlatinib using genetically modified mouse strains. In vitro, human ABCB1 and mouse Abcg2 modestly transported lorlatinib. Following oral lorlatinib administration (at 10 mg/kg), brain accumulation of lorlatinib, while relatively high in wild-type mice, was still fourfold increased in Abcb1a/1b-/- and Abcb1a/1b;Abcg2-/- mice, but not in single Abcg2-/- mice. Lorlatinib plasma levels were not altered. Oral coadministration of the ABCB1/ABCG2 inhibitor elacridar increased the brain accumulation of lorlatinib in wild-type mice fourfold, that is, to the same level as in Abcb1a/1b;Abcg2-/- mice, without altering plasma exposure. Similar results were obtained for lorlatinib testis accumulation. In Cyp3a-/- mice, the plasma exposure of lorlatinib was increased 1.3-fold, but was then twofold reduced upon transgenic overexpression of human CYP3A4 in liver and intestine, whereas relative tissue distribution of lorlatinib remained unaltered. Our data indicate that lorlatinib brain accumulation is substantially limited by P-glycoprotein/ABCB1 in the blood-brain barrier, but this can be effectively reversed by elacridar coadministration. Moreover, oral availability of lorlatinib is markedly restricted by CYP3A4 activity. These insights may be used in optimizing the therapeutic application of lorlatinib.

Abstract 4796: Ropotrectinib is a novel polypharmacology kinase inhibitor against WT and mutant ROS1, TRK and ALK

Abstract Tyrosine kinase inhibitors (TKI) have achieved great success for cancer patients with aberrant target genes such as ROS1, NTRKs and ALK. However, the inevitable emergence of drug resistance limits their long-term clinical benefits. Ropotrectinib (TPX-0005), a brain-tumor penetrable ROS1/TRK/ALK kinase inhibitor, was designed not only to target abnormal activity of ROS1, TRK and ALK but also to overcome drug resistance caused by previous ROS1, NTRK and ALK inhibitors. The unique structure design of roporectinib granted it the unique ability to overcome acquired solvent front mutations in the targeted kinase domain caused by other TKIs. Moreover, ropotrectinib displays inhibitory activity for SRC/FAK/JAK2, rendering its potential to overcome drug resistance caused by “by-passing” mechanisms such as EMT. Ropotrectinib is a superb ROS1 inhibitor. The ALK/ROS1/MET inhibitor crizotinib has been approved by FDA to treat NSCLC patients harboring a rearranged ROS1 fusion gene. Acquired secondary mutations in ROS1 kinase domain is a common drug resistance mechanism in 50-60% patients progressed on crizotinib treatment, with solvent front mutations most frequently observed. Compared to other ROS1 inhibitors, such as lorlatinib, ceritinib, brigatinib and entrectinib, ropotrectinb demonstrated most potent activity against WT and mutant ROS1, especially solvent front mutations such as G2032R in cellular assays and potently inhibited xenograft tumors. Ropotrectinib is the most potent TRK inhibitors in clinic, with IC50s &amp;lt; 1nM in cellular assays. Preclinic in vitro and in vivo studies further demonstrated that ropotrectinib overcomes clinical resistance mutations which occur in patients progressed on TRK inhibitors, such as entrectinib and larotrectinib. In a phosphorylation assay using engineered NIH3T3 cells expressing a TRKAG595R fusion gene, ropotrectinib (IC50 &amp;lt; 0.1nM) exhibited activities at least ten folds more potent than the recently reported activity of LOXO-195 (IC50 = 7nM), a second generation of TRK inhibitor in clinic. Ropotrectinib is also a ALK inhibitor with CNS activity, inhibiting growth and viability of ALK+ cells, inducing tumor regression in a ALK+ PDX tumor model and significantly improving overall survival of mice bearing CNS ALK+ H2228 tumors. In particular, compared to previous generations of ALK inhibitors (e.g. crizontinib, ceritinib, alectinib, and brigatinib), it exhibited superb activity in those acquired mutations, especially the G1202R solvent front mutation and double mutations containing L1198F. Roporectinib dose-dependently down-regulated EGFR, CD44 and vimentin expression levels via SRC/FAK inhibition, suggesting a potential to prevent EMT. In summary, ropotrectinib exerts unique pharmacological properties for clinical applications in patients harboring aberrant ROS1/TRK/ALK. A Phase 1/2 clinical trial of TPX-0005 is actively pursued (NCT03093116). Citation Format: Wei Deng, Dayong Zhai, John Huang, Evan Rogers, Jeffrey Whitten, John Lim, Yishan Li, Jean Cui. Ropotrectinib is a novel polypharmacology kinase inhibitor against WT and mutant ROS1, TRK and ALK [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 4796.