ROS1 G2032R

In this study we knock-in for the first time in a ROS1 + patient-derived cell line, three different known resistance-causing mutations using CRISPR/Cas9 in the endogenous translocated ROS1 alleles. Pharmacological assays performed in 2D and 3D cell culture revealed that spheroids are more sensitive to TKIs than cells cultured as a monolayer. This direct comparison between two culture systems could be done thanks to the implementation of normalized growth rates (NGR) to uniformly quantify drug response between 2D and 3D cell culture. Overall, this study presents the added value of using spheroids and positions lorlatinib and repotrectinib as the most effective TKIs against the studied ROS1 resistance point mutations.

This study provided a comprehensive portrait of TKI-resistance mechanisms in ROS1+ NSCLC patients. Using in silico simulations of TKI activity, novel secondary mutations that may confer TKI resistance were identified and may support clinical therapeutic decision-making.

These findings confirm crizotinib's sustained clinical efficacy and safety in a real-world context, which was characterized by a higher elderly population and higher rates of brain/CNS metastases. The study highlights the clinical relevance of liquid biopsy for detecting resistance mechanisms, suggesting its value in personalized treatment strategies.

Repotrectinib had durable clinical activity in patients with ROS1 fusion-positive NSCLC, regardless of whether they had previously received a ROS1 TKI. Adverse events were mainly of low grade and compatible with long-term administration. (Funded by Turning Point Therapeutics, a wholly owned subsidiary of Bristol Myers Squibb; TRIDENT-1 ClinicalTrials.gov number, NCT03093116.).

Despite ROS1 fusion positive (ROS1+) NSCLC accounting approximately 1-2% of NSCLC, there is a dizzying list of ROS1 tyrosine kinase inhibitor (TKIs) being developed in addition to two approved ROS1 TKIs, crizotinib and entrectinib...Additionally, the less known central β-sheet 6 (Cβ6) mutation ROS1 L2086F confer resistances to next-generation ROS1 TKIs (taletrectinib, lorlatinib, potentially NVL-520) that can be overcome by cabozantinib as documented in published patient reports and may potentially by certain L-shaped Type I ROS1 TKIs including gilteritinib which is approved as a FLT3 inhibitor for AML. Future clinical trials should investigate cabozantinib and gilteritinib to repurpose them as ROS1 TKIs that can target Cβ6 mutation.

In line with its activity, we documented the presence of the drug at potentially active concentrations in the cerebrospinal fluid. Nevertheless, the short-lived response reported by our patient highlights the importance for novel ROS1-tyrosine kinase inhibitors (TKIs) to be specifically developed to be able to penetrate the blood-brain barrier.

No treatment-related AE (TRAE) led to discontinuation or death; 24% of pts had a TRAE leading to dose reduction. Conclusions In this ongoing global pivotal phase 2 study, taletrectinib demonstrated robust and consistent clinical activity with TRUST-I, including high response rates and a tolerable safety profile in both TKI-naive and TKI-pretreated pts with ROS1+ NSCLC.

With 14 months' minimum follow-up in TRIDENT-1, repotrectinib continued to demonstrate durable efficacy in patients with ROS1+ NSCLC, including intracranial activity, in both TKI-naïve and 1 prior TKI and no chemo cohorts. Safety in patients treated at RP2D was manageable, consistent with previous reports in all treated patients.

Osimertinib-resistant YU-1097 harboring EGFR resistance mutation (E19del/T790M/C797S) revealed sensitivity to BLU-945 (IC50, 108nM), a novel fourth-generation EGFR-TKI. A similar inhibition of cell viability was observed with repotrectinib (IC50, 21nM), a next-generation ROS1-TKI and lorlatinib (IC50, 9nM) in YU-1078 harboring CD74-ROS1, whereas more robust tumor regression was seen with repotrectinib in YU1078-derived xenograft model. Amivantamab, a EGFR-MET bispecific antibody, showed a robust activity in YU-1163 and YUO-036 in vitro and in vivo. PDC/PDO models can be utilized for evaluating activity of novel agents and will accelerate novel drug development in NSCLC.

Results G2032R line showed in 2D the strongest resistance towards crizotinib, entrectinib and ceritinib, having all a weak activity (IC50 s around 1,1 μM), opposed to repotrectinib (93,25 nM) and lorlatinib (317,17 nM). These results were confirmed by western blot. Our approach allows the generation of patient-derived mutant cell lines and screened for TKI sensitivity guided by the in silico modelling of ROS1 variants.

CRZ, crizotinib; DCR, disease control rate; NE, not evaluable; ORR, overall response rate; PFS, progression-free survival; TKI, tyrosine kinase inhibitor. Conclusions With additional follow-up, taletrectinib continued to demonstrate meaningful efficacy outcomes including high response rates, prolonged PFS, robust intracranial activity, activity against G2032R, and tolerable safety with low incidence of neurological AEs.

With a longer follow-up, repotrectinib remains well tolerated with a manageable safety profile. Efficacy and safety were generally consistent across age subgroups.

Introduction: Lorlatinib demonstrated activity in crizotinib-refractory ROS1+ NSCLC, especially in absence of acquired ROS1 mutations. In the PFROST study, presence of TP53 mutations identified a subset of ROS1+ individuals at high risk of progression and death for which more potent and aggressive strategies are needed.

He played a monumental role in developing repotrectinib, lazertinib, amivantamab, and other targeted- and immuno-therapies, many of which were acknowledged for breakthrough therapy designation and FDA approval. Repotrectinib achieves durable activity, including intracranial responses, in TKI-naïve and TKI-pretreated patients with ROS1+ advanced NSCLC, and those with ROS1 G2032R. Repotrectinib safety is well characterized, manageable, and compatible with long-term use.

No grade greater than or equal to 4 adverse events were observed. Lorlatinib induced durable intracranial responses in patients with ROS1-rearranged NSCLC and prior isolated CNS progression on crizotinib.

Patients with ALK+ NSCLC experienced more unfavorable prognosis and were more prone to develop CNS progression compared with those with ROS-1+ NSCLC following the treatment of crizotinib.ROS-1ALKP valueExtrathoracic metastases62.5%(25/40)77.8%(35/45)0.155CNS metastases20%(8/40)26.7%(12/45)0.61Multiple CNS metastases62.5%(5/8)50%(6/12)0.67Measurable CNS lesions37.5%(3/8)50%(6/12)0.67Liver metastases7.5%(3/40)17.8%(8/45)0.204Bone metastases27.5%(11/40)42.2%(19/45)0.117≥3 distant organs involved25%(10/40)31.1%(14/45)0.632

Introduction: In crizotinib-refractory ROS1+ non small-cell lung cancer NSCLC, lorlatinib showed intracranial and systemic activity especially in absence of acquired ROS1 mutations. In our trial, presence of TP53 mutations identified a subset of ROS1+ individuals at high risk of progression and death. Different and/or more aggressive strategies should be investigated in this specific population.

Taletrectinib demonstrated meaningful clinical efficacy in both TKI-naïve and crizotinib-pretreated ROS1 positive NSCLC patients. In particular, taletrectinib showed clinical effectiveness in patients with ROS1 secondary G2032 mutations and patients with brain metastasis. Taletrectinib was well tolerated in this patient population.

The study consists of four cohorts: cohort 1: systemic chemotherapy naïve or ≤ one prior line and ROS1 TKI naïve NSCLC (N = 53); cohort 2: previously treated with one ROS1 TKI (crizotinib or entrectinib) and with progression who are either chemotherapy naïve or ≤ one line of platinum and/or pemetrexed based therapy for NSCLC (N = 46); cohort 3: ≤ 2 prior ROS1 TKIs and with progression who are either chemotherapy naïve or ≤ 2 lines of platinum and/or pemetrexed based therapy for NSCLC (N = 10); and cohort 4: systemic chemotherapy naïve or ≤ 2 prior lines of chemotherapy, but ROS1-TKI naïve ROS1 positive solid tumor other than NSCLC (N = 10). This study is currently recruiting in Japan, Republic of Korea, and USA. Additional accrual is planned in Canada, China, and European Union.

Crizotinib and entrectinib are FDA-approved ROS1 tyrosine kinase inhibitors (TKIs), but clinical emergence of ROS1 resistance mutations S1986F/Y, F2004C/I/V, L2026M, G2032R, and D2033N restricts their therapeutic utility...TRKB inhibition in the central nervous system has been implicated in adverse events observed with FDA-approved dual TRK/ROS1 inhibitor entrectinib and FDA-approved ALK inhibitor lorlatinib...In conclusion, the preclinical profile of NVL-520 supports its potential to address a medical need for patients with a diverse array of ROS1 fusion partners and kinase-domain mutations, both in NSCLC and in other cancers such as glioblastoma. NVL-520 is being evaluated in a Phase 1/2 clinical trial for patients with advanced ROS1-positive NSCLC or other solid tumors (NCT05118789).

The study consists of four cohorts: cohort 1: systemic chemotherapy naïve or ≤ one prior line and ROS1 TKI naïve NSCLC (N=53); cohort 2: previously treated with one ROS1 TKI (crizotinib or entrectinib) and with progression who are either chemotherapy naïve or ≤ one line of platinum and/or pemetrexed based therapy for NSCLC (N=46); cohort 3: ≤ 2 prior ROS1 TKIs and with progression who are either chemotherapy naïve or ≤ 2 lines of platinum and/or pemetrexed based therapy for NSCLC (N=10); and cohort 4: systemic chemotherapy naïve or ≤ 2 prior lines of chemotherapy, but ROS1-TKI naïve ROS1-positive solid tumor other than NSCLC ( N=10). This study is currently recruiting in Japan, Republic of Korea, and USA. Additional accrual is planned in Canada, China, and European Union.

No grade 5 adverse events were observed. The study was terminated early after enrollment of 16 of 22 planned patients due to the commercial availability of off-label lorlatinib.Conclusion s : The CNS-penetrant next-generation ROS1 inhibitor lorlatinib is an effective salvage therapy for patients experiencing isolated CNS progression on crizotinib.

These findings suggest that if ROS1 IHC was used as a screening tool for ROS1 fusion, a subset of fusion-negative tumors will reveal positive IHC staining highlighting the value of reflexing to genomic profiling to confirm the presence of a targetable fusion-driver before the initiation of therapy. In addition, the ability of comprehensive genomic profiling to detect ROS1 resistance mutations will be important for clinical decision making.

Grade 3 or higher adverse events were alanine transaminase elevations (18.2%), aspartate transaminase (9.1%), and diarrhea (4.5%). Taletrectinib (AB106/DS6051b) has a meaningful clinical activity in patients with advanced ROS1+ NSCLC who are ROS1 TKI-naive or crizotinib-refractory and a manageable safety profile.

While the 1st generation TKIs larotrectinib (LOXO101, LAR), entrectinib (ENT) and crizotinib (CRI) have provided effective initial treatment for patients with cancers harboring these mutations, acquired resistance including secondary kinase domain mutations invariably arise. Kinase and cell proliferation inhibition and in vivo antitumor activity were determined using recombinant kinases and engineered NIH3T3 or Ba/F3 cells expressing WT or mutated TRKs and ROS1, respectively...Against the resistant solvent-front (G595R) mutant AGX87 was >1000-fold more potent (IC50=0.2 nM) than LAR and ENT and 20-fold more potent than LOXO195... AGX87 demonstrated best-in-class activity against WT and mutated TRKs and ROS1 and exhibited excellent drug-like properties. IND enabling studies are in progress.

ROS1 mutations mediate resistance to crizotinib and lorlatinib in over one-third of cases, underscoring the importance of developing next-generation ROS1 inhibitors with potency against these mutations including G2032R and L2086F. Continued efforts are needed to elucidate ROS1-independent resistance mechanisms.

Neither prior treatments with second-generation TKIs nor BM had a significant influence on PFS and OS. Our data from real-life practice demonstrate the efficacy of lorlatinib in mostly heavily pretreated patients, providing a clinically meaningful option for patients with resistance mutations not covered by other targeted therapies and those with BM or leptomeningeal carcinomatosis.

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...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.

Next-generation, targeted, amplicon-based sequencing for liquid biopsy specimen profiling provides clinically relevant detection of ALK/ROS1 fusions in TKI-naïve patients and allows for the identification of resistance mutations in patients treated with TKIs. Liquid biopsy specimens from patients treated with TKIs may affect clinical outcomes and capture heterogeneity of TKI resistance, supporting their role in selecting sequential therapy.

In addition, SAF-189s was more potent than crizotinib and comparable to lorlatinib, the most advanced ROS1i known against the ROS1. 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).

The tyrosine kinase inhibitors (TKIs), crizotinib, lorlatinib, and entrectinib have demonstrated favorable efficacy in treating ROS1-rearranged NSCLCs. ROS1 mutations, including G2032R were observed in approximately 33% of post-crizotinib samples. Collectively, we report the prevalence of ROS1 fusions in a large-scale NSCLC population, and the efficacy of crizotinib in treating patients with ROS1-rearranged NSCLC.

We describe cases of advanced ROS1-rearranged lung cancer receiving crizotinib, entrectinib, and/or lorlatinib in first and later line treatment settings to dissect the current state of evidence supporting management decisions for these patients. The next generation ROS1 TKIs (repotrectinib and DS-6051b), owing to their broad activity against kinase mutations including ROS1-G2032R in preclinical studies, hold promise to transform the current treatment paradigm and permit even further gains with regards to long-term outcomes in this subset of patients.

First-line crizotinib treatment is beneficial in Chinese patients with ROS1-rearranged advanced NSCLC. Resistance to crizotinib correlated with the G2032R mutation in the ROS1 kinase domain.

Taletrectinib has manageable toxicities at the MTD of 800 mg daily. Preliminary efficacy was observed in crizotinib-refractory ROS1+ NSCLC patients.

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. 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.

In vivo efficacy results show that this triple mutant NSCLC PDX model was resistant to Erlotinib and AZD9291 and sensitive to the combination of Cetuximab and Brigatinib. We also established CD74-ROS1 fusion and G2032R mutant NSCLC PDX model; EML4-ALK fusion and L1196M mutant NSCLC PDX model; Olaparib resistant Ovarian cancer PDX model; Heceptin resistant gastric PDX model; Rituximab and ABT-199 resistant DLBCL PDX model, and so on. In conclusion, these precious PDX models provide insight into resistance mechanisms as well as serve as models to develop new therapeutics drug candidates that overcome the drug resistant.