ROS1-rearranged Patients Research Articles

Real-World Management and Outcomes of Crizotinib-Treated ROS1-Rearranged NSCLC: A Retrospective Canadian Cohort.

The use, safety and effectiveness of crizotinib as part of the management of ROS1-rearranged NSCLC patients in a real-world Canadian clinical cohort was the focus of this retrospective review. Twenty-one ROS1-rearranged patients with advanced/metastatic disease receiving crizotinib between 2014–2020 were identified; crizotinib demonstrated tolerability and effectiveness in this population where outcomes were similar to those described in other crizotinib-treated real-world cohorts, but lower than those of the PROFILE 1001 clinical trial population. Systemic anti-cancer therapy prior to crizotinib initiation occurred in half of the study cohort, with platin-pemetrexed and immune checkpoint inhibitors being most common. Platin-pemetrexed showed good effectiveness in this cohort, but despite high prevalence of upregulated PD-L1 expression, immune checkpoint inhibitors showed poor effectiveness in his cohort. Among all systemic therapies received, crizotinib showed the most effective disease control, although longer intervals between diagnosis and crizotinib initiation were more common among those showing a lack of clinical response to crizotinib, and patients with brain metastases at the time of crizotinib initiation also showed increased diagnosis to crizotinib initiation intervals and decreased clinical response to crizotinib. This study reveals crizotinib has clinical benefit, but timely identification of ROS1-rearrangements and initiation targeted therapies appears important to maximize outcome in this population.

Abstract 741: Molecular and clinicopathological characteristics of Chinese non-small cell lung cancers with ROS1 gene fusions identified by next-generation sequencing

Abstract Background ROS1 gene rearrangements are reported at a prevalence of 1-2% in unselected cancer populations including non-small cell lung cancer (NSCLC), and notably higher in lung adenocarcinoma. More than twenty ROS1 fusion partners have been identified, which continues to increase due to the adoption of next-generation sequencing (NGS) for genetic testing. The tyrosine kinase inhibitors (TKIs) including crizotinib, lorlatinib, and entrectinib, have demonstrated favorable efficacy in the treatment of ROS1-rearranged NSCLCs. Methods A total of 17,158 Chinese non-small cell lung cancer (NSCLC) patients whose tumor specimen and/or circulating cell-free DNA (cfDNA) underwent genomic profiling by hybridization capture-based targeted NGS of exons and introns of cancer related genes were retrospectively reviewed. Clinical characteristics, treatment history, and progression-free survival (PFS) for crizotinib of a subset of 37 patients were further evaluated. Results A total of 288 ROS1-positive NSCLC patients were identified in the cohort at a frequency of 1.7% (288/17158). ROS1 fusions retaining the intact ROS1 kinase domain were confirmed in a subset of 258 patients (1.5%) with the most common fusion partner being CD74 (104/258, 40%), followed by EZR (34/258, 13%), SDC4 (28/258, 11%), SLC34A2 (27/258, 11%), and other recurrent ones at low frequency including TPM3, GOPC, MYH9, and CCDC6. Most frequent breakpoints on ROS1 are spreading in introns 33 (37%), 31 (25%), 32 (17%) and 34 (11%) with no obvious hotspots. 5.4% of cases (14/258) were fused to intergenic regions (IGR), mainly on the same chromosome of ROS1, with unknown fusion products. Notably, CD74 (63%) and EZR (50%) are more frequently fused with ROS1 intron 33, while ROS1 intron 31 was the most common breakpoint region of fusion events involving SDC4 (79%) and SLC34A2 (81%). Median PFS (mPFS) was not significantly different between fusions involving breakpoints in ROS1 introns 31-34 for crizotinib treatment, whereas non-CD74 patients (n=23) trended to demonstrate longer mPFS than that of CD74-ROS1 cases (n=14) (12.0 versus 9.9 months). Previously reported acquired resistance to crizotinib in ROS1-rearranged patients, including ROS1 G2032R and S1986F mutations, were observed in 11 out of 37 patients upon disease progression. In addition, two out of three patients who had uncharacterized fusion partners (IGR-ROS1) achieved durable clinical benefit on crizotinib. Conclusion We hereby report the prevalence of ROS1 fusions of 1.7% in a large Chinses NSCLC population detected by NGS testing and the most frequent fusion partners including CD74, EZR, SDC4, and SLC34A2. Crizotinib has demonstrated robust response in treating ROS1-rearranged NSCLC, particularly in non-CD74 ROS1-positive patients. Keywords ROS1, gene fusion, non-small cell lung cancer, crizotinib, breakpoint, next-generation sequencing Citation Format: Dongling Gao, Yuchen Han, Zhihua Zhao, Qiuxiang Ou, Xiaoling Tong, Ruiying Zhao, Nan Dong, Xue Wu, Wencai Li, Guozhong Jiang. Molecular and clinicopathological characteristics of Chinese non-small cell lung cancers with ROS1 gene fusions identified by next-generation sequencing [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 741.

P1.01-104 Survivals in ROS1-Rearranged Advanced Non-Small-Cell Lung Cancer Treated with First-Line Crizotinib

The c-ros oncogene 1 (ROS1)-rearranged non-small-cell lung cancer (NSCLC) can be treated effectively with crizotinib, a tyrosine kinase inhibitor (TKI) of anaplastic lymphoma kinase (ALK), ROS1, and mesenchymal-epithelial transition (MET). However, few studies have investigated on survivals in ROS1-rearranged advanced NSCLC patients treated with first-line crizotinib. We retrospectively analyzed clinicopathological and survival data of ROS1-rearranged patients with advanced NSCLC treated with crizotinib between August 2013 and January 2019 at the Guangdong Provincial People’s Hospital. ROS1 rearrangements were detected by Reverse Transcription-Ploymerase Chain Reaction(RT/PCR),Fluorescence in situhybridization (FISH), or Next-generation Sequencing (NGS) . Overall survival (OS) and progression-free survival (PFS) were compared between first-line crizotinib, chemotherapy followed by crizotinib and first-line chemotherapy without any subsequent targeted therapy. Among totally 40 patients with ROS1-rearranged advanced NSCLC, 29 were treated with crizotinib (16 with first-line; 13 with second- or further-line), and 11 were not treated with crizotinib at data cutoff (April 4, 2019). Median OS was significantly prolonged in patients with first-line crizotinib (N=16) than those with first-line chemotherapy followed by subsequent crizotinib (N=9), not reached vs. 27.1 months, P=0.042. However, there was no significant difference in median PFS between the two groups, 16.3 vs. 5.7 months, P=0.054. Meanwhile, first-line crizotinib (N=16) was significantly superior to first-line chemotherapy without any subsequent targeted therapy (N=8) in both median OS (not reached vs. 9.1 months, P=0.024) and PFS (16.3 vs. 4.8 months, P=0.017). First-line crizotinib prolongs survivals than chemotherapy for patients with ROS1-rearranged advanced NSCLC.

Crizotinib versus pemetrexed-based chemotherapy in patients with advanced ROS1-rearranged non-small cell lung cancer.

9101 Background: ROS1 rearrangement is an important therapeutic target that occurs in approximately 1-2% of patients with non-small cell lung cancer (NSCLC). It has been shown that ROS1-rearranged patients could benefit from crizotinib treatment. However, the efficacy of crizotinib as compared with pemetrexed-based chemotherapy in such patients is unknown. Methods: Advanced ROS1-rearranged NSCLC patients receiving crizotinib or pemetrexed-based chemotherapy as first-line treatment in Shanghai Chest Hospital between August 2010 and December 2017 were retrospectively reviewed. Clinical characteristics, treatments and survival outcomes data were abstracted. Results: Of 77 patients included, 30 patients (39.0%) received crizotinib and 47 patients (61.0%) received pemetrexed-based chemotherapy as their first-line treatment. The median follow-up was 26.8 months. The objective response rate was significantly better with crizotinib than with pemetrexed-based therapy (86.7% vs 44.7%, P < 0.001). The disease control rate wasc 96.7% with crizotinib, as compared with 85.1% with pemetrexed-based therapy (P = 0.140). The median progression-free survival was significantly longer with crizotinib versus pemetrexed-based therapy (18.4 months [95% confidence interval [CI]: 6.8-30.0] vs 8.6 months [95% CI:7.1-10.2], P < 0.001). No significant difference in overall survival (OS) was observed between the two groups (Not reach vs 28.1 months [95% CI:18.7-38.5], P = 0.173). Six patients (20%) in the crizotinib group switched to pemetrexed-based therapy in subsequent lines, while twenty-nine patients (61.7%) in the chemotherapy group crossed over to receive crizotinib after progression. There was no significant difference in median OS between patients who received crizotinib first and those who received pemetrexed-based treatment prior to crizotinib (38.6 months [95% CI: 0-81.0] vs 32.7 months [95% CI:14.3-51.1], P = 0.890). Conclusions: Crizotinib is superior to pemetrexed-based chemotherapy as an initial treatment for advanced ROS1-rearranged NSCLC patients. The sequence of crizotinib treatment and pemetrexed-based chemotherapy does not influence OS.

Clinicopathological characteristics of ROS1- and RET-rearranged NSCLC in caucasian patients: Data from a cohort of 713 non-squamous NSCLC lacking KRAS/EGFR/HER2/BRAF/PIK3CA/ALK alterations.

Targeted therapies have substantially changed the management of non-small cell lung cancer (NSCLC) patients with driver oncogenes. Given the high frequency, EGFR and ALK aberrations were the first to be detected and paved the way for tyrosine kinase inhibitor (TKI) treatments. Other kinases such as ROS1 and more recently RET have emerged as promising targets, and ROS1 and RET TKIs are already available for precision medicine.We screened a large cohort of 713 Caucasian non-squamous NSCLC patients lacking EGFR/KRAS/BRAF/HER2/PI3KCA/ALK aberrations for ROS1 and RET rearrangements using fluorescence in situ hybridization to determine the frequency and clinicopathological characteristics of ROS1- and RET-positive patients.Frequencies of ROS1 and RET rearrangements were 2.1% and 2.52%, respectively. Contrary to common belief, both ROS1 and RET rearrangements were detected in patients with a history of smoking, and the RET-positive patients were not younger than the negative patients. Moreover, RET but not ROS1 rearrangement was associated with the female gender. Nearly half of the ROS1-rearranged patients were successfully treated with ROS1 TKIs. In contrast, only 5/18 RET-positive patients received off-label RET TKIs. Two patients had stable disease, and three experienced disease progression. In addition to the 18 RET-positive cases, 10 showed isolated 5′ signals. The clinical relevance is unknown but if the frequency is confirmed by other groups, the question whether these patients are eligible to TKIs will arise. More potent RET TKIs are under development and may improve the response rate in RET-positive patients. Therefore, we recommend the routine implementation of RET testing in non-squamous NSCLC patients, including those with a history of smoking.

ROS1 rearrangement and response to crizotinib in Stage IV non-small cell lung cancer.

Background:The frequency of ROS1 rearrangement in non-small cell lung cancers has been reported from 1.6% to 2.3%.Materials and Methods:We examined 105 lung adenocarcinoma patients for ROS1 rearrangement which were negative for EGFR and anaplastic lymphoma kinase. Clinical characteristics of ROS1 rearranged patients and their responses to crizotinib therapy were studied.Results:Of the 105 patients, three cases were positive for ROS1 rearrangement by fluorescence in situ hybridization analysis. All of them showed heterogeneous pattern. All the 3 ROS1-positive patients were females in their forties and started on crizotinib. All of them responded to treatment. One of them developed resistance after 3 months. Another one showed marked systemic response but central nervous system lesions progressed. The third case is doing well till date with inactive lesions on positron emission tomography scan.Conclusions:The frequency of ROS1 rearrangement is low in non-small cell lung carcinoma, but their diagnosis offers patients an opportunity to receive highly effective targeted therapies.

ROS1 copy number alterations are frequent in non-small cell lung cancer.

ObjectivesWe aimed to determine the prevalence and partners of ROS1 rearrangements, to explore the correlation between FISH and IHC assays, and to investigate clinical implications of ROS1 copy number alterations (CNAs).MethodsA total of 314 NSCLC patients were screened using ROS1 FISH break-apart probes. Of these, 47 surgical tumors were included in TMAs to analyze ROS1 heterogeneity assessed either by FISH and IHC, and chromosome 6 aneusomy. To characterize ROS1 partners, probes for CD74, EZR, SLC34A2 and SDC3 genes were developed. ROS1 positive FISH cases were screened also by IHC.ResultsFive patients were ROS1 positive (1.8%). We identified two known fusion partners in three patients: CD74 and SLC34A2. Four out of five ROS1 rearranged patients were female, never smokers and with adenocarcinoma histology. Rearranged cases were also positive by IHC as well. According to ROS1 CNAs, we found a prevalence of 37.8% gains/amplifications and 25.1% deletions.ConclusionsThis study point out the high prevalence of ROS1 CNAs in a large series of NSCLC. ROS1 gains, amplifications and deletions, most of them due to chromosome 6 polysomy or monosomy, were heterogeneous within a tumor and had no impact on overall survival.

High level of chromosomal instability in circulating tumor cells of ROS1-rearranged non-small-cell lung cancer

Genetic aberrations affecting the c-ros oncogene 1 (ROS1) tyrosine kinase gene have been reported in a small subset of patients with non-small-cell lung cancer (NSCLC). We evaluated whether ROS1-chromosomal rearrangements could be detected in circulating tumor cells (CTCs) and examined tumor heterogeneity of CTCs and tumor biopsies in ROS1-rearranged NSCLC patients. Using isolation by size of epithelial tumor cells (ISET) filtration and filter-adapted-fluorescence in situ hybridization (FA-FISH), ROS1 rearrangement was examined in CTCs from four ROS1-rearranged patients treated with the ROS1-inhibitor, crizotinib, and four ROS1-negative patients. ROS1-gene alterations observed in CTCs at baseline from ROS1-rearranged patients were compared with those present in tumor biopsies and in CTCs during crizotinib treatment. Numerical chromosomal instability (CIN) of CTCs was assessed by DNA content quantification and chromosome enumeration. ROS1 rearrangement was detected in the CTCs of all four patients with ROS1 rearrangement previously confirmed by tumor biopsy. In ROS1-rearranged patients, median number of ROS1-rearranged CTCs at baseline was 34.5 per 3 ml blood (range, 24-55). In ROS1-negative patients, median background hybridization of ROS1-rearranged CTCs was 7.5 per 3 ml blood (range, 7-11). Tumor heterogeneity, assessed by ROS1 copy number, was significantly higher in baseline CTCs compared with paired tumor biopsies in the three patients experiencing PR or SD (P < 0.0001). Copy number in ROS1-rearranged CTCs increased significantly in two patients who progressed during crizotinib treatment (P < 0.02). CTCs from ROS1-rearranged patients had a high DNA content and gain of chromosomes, indicating high levels of aneuploidy and numerical CIN. We provide the first proof-of-concept that CTCs can be used for noninvasive and sensitive detection of ROS1 rearrangement in NSCLC patients. CTCs from ROS1-rearranged patients show considerable heterogeneity of ROS1-gene abnormalities and elevated numerical CIN, a potential mechanism to escape ROS1-inhibitor therapy in ROS1-rearranged NSCLC tumors.

Clinicopathological characteristics and outcomes of ROS1-rearranged patients with lung adenocarcinoma without EGFR, KRAS mutations and ALK rearrangements.

Backgroundc-ros oncogene 1 (ROS1) rearrangement presents one of the newest molecular targets in non-small cell lung cancer (NSCLC). ROS1 rearrangement is predominantly found in adenocarcinoma cases and is exclusive to other oncogenes, such as epidermal growth factor receptor (EGFR), Kirsten rat sarcoma viral oncogene homolog (KRAS), and anaplastic lymphoma kinase (ALK). The aim of this study was to investigate the clinicopathological characteristics and outcomes of ROS1-rearranged patients with lung adenocarcinoma without EGFR and KRAS mutations and ALK rearrangements.MethodsWild-type EGFR/KRAS/ALK patients with lung adenocarcinoma were selected from Beijing Chest Hospital. Specimens were conducted in tissue microarrays. ROS1 rearrangement was screened using fluorescence in situ hybridization.ResultsOur study included 127 patients with lung adenocarcinoma without EGFR and KRAS mutations and ALK rearrangements. ROS1 rearrangement was detected in five (3.9%) of the 127 patients. Compared with ROS1-negative patients, the positive rate of ROS1 in female patients was significantly higher than in male patients (9.8% vs. 0.0%, P = 0.009). There were no differences in age, smoking status, stage or histological subtype between ROS1-positive and ROS1-negative patients. No significant difference in survival was detected between the ROS1-positive and ROS1-negative patients.ConclusionsROS1 rearrangement is a rare subset of lung adenocarcinoma. In 127 patients with lung adenocarcinoma, 3.9% of ROS1-positive patients with wild-type EGFR/KRAS/ALK were found.

202P - Coexistence of Egfr Mutations with Alk, Ros1 or Ret Rearrangements in Lung Adenocarcinoma: a Clinicopathological Analysis from 646 Chinese Patients with Lung Adenocarcinoma

ABSTRACT Aim: We investigated the incidence of concomitant EGFR mutations and ALK, ROS1 or RET rearrangements in Chinese patients with lung adenocarcinoma and analyzed the clinicopathological characteristics of concomitant EGFR mutations with known fusion genes in lung adenocarcinoma. Methods: We screened 646 patients with lung adenocarcinoma for EGFR using amplification-refractory mutation system (ARMS) assay, and for ALK, ROS1 and RET status using RT-PCR assay. All positive samples were validated by direct sequencing. The clinicopathological characteristics of dual alterations was analyzed. Results: EGFR mutations were found to coexist with fusion genes in 27 (4.2%) patients with lung adenocarcinoma. Of these, EGFR/ALK, EGFR/ROS1 and EGFR/RET co-alterations were identified in 12, 7, and 8 samples, respectively. EGFR/ALK co-alterations were found in 3.2% EGFR-mutated patients and 24% ALK-rearranged patients. EGFR/ROS1 co-alterations were found in 1.9% EGFR-mutated patients and 33.3% ROS1-rearranged patients. EGFR/RET co-alterations were found in 2.2% EGFR-mutated patients and 57.1% RET-rearranged patients. The median age of patients with co-alteration were 56 (range from 28 to 75). Nineteen of 27 (70.4%) patients with dual alterations were female. There was no statistically significant difference in age, gender, smoking status, pathological stage, and adenocarcinoma subtype (according to the 2011 IASLC/ATS/ERS International Multidisciplinary Classification of Lung Adenocarcinoma) between coexistence and non-coexistence groups. RET/EGFR co-alterations seem to be more common in lepidic predominant adenocarcinoma, and ALK/EGFR co-alterations might occur more frequently in patients with resectable lesion (I-IIIa stage), with a borderline statistical significance (p = 0.062). The median overall survival (mOS) was 74.5 months in non-coexistence group, and the mOS was not reached in coexistence group. Conclusions: EGFR mutations could coexist with ALK, ROS1 or RET rearrangements, with an incidence of 1.0-1.8% of Chinese patients with lung adenocarcinoma. Coexistence of EGFR mutations with fusion genes might be associated with lepidic predominant adenocarcinoma, which is being investigated. Patients with concomitant EGFR mutations and ALK, ROS1 or RET rearrangements might have a better prognosis. Disclosure: All authors have declared no conflicts of interest.

Clinical significance of ROS1 rearrangements in non-small cell lung cancer

最近研究显示，包括非小细胞肺癌（non-small cell lung cancer, NSCLC）在内的许多恶性肿瘤存在ROS1受体酪氨酸激酶基因重排。ROS1基因重排作为一种新发现的NSCLC亚型，其发生率约占NSCLC的1%-2%，优势人群通常为年轻、不吸烟的肺腺癌患者，这些临床特征与ALK重排的NSCLC患者类似。体外实验和早期临床试验均显示，克唑替尼对ROS1重排阳性的癌症患者具有明显的抗肿瘤活性，治疗第8周和第16周时疾病控制率分别为76%和60%，治疗患者的总缓解率为56%。进一步了解ROS1基因重排在NSCLC发病中的作用，提高ROS1基因重排的检测技术，发现ROS1重排患者及研发特异性ROS1激酶抑制剂将为肿瘤个体化治疗增添新的篇章。