2nd TKIs Research Articles

First-in-human, multicenter phase Ⅰ study of TGRX-326 in patients with advanced ALK-positive non-small cell lung cancer.

9113 Background: TGRX-326, a deuterated derivative of lorlatinib (LOR), is a potent 3rd generation ALK and ROS1 dual TKI with high potency against multiple ALK-resistant mutations. Deuteration of the key metabolic site of the molecule allows to achieve a higher exposure than with LOR and this may result in alleviated toxicities and better efficacy. Methods: The study comprised 3 phases: dose escalation (D-ESCAL), dose expansion (D-EXP) and cohort expansion (C-EXP). In D-ESCAL and D-EXP, ALK+ pts prior failed on 2nd gen ALK-TKIs or ROS1+ pts resistant to crizotinib (CRZ) were enrolled; in C-EXP, ALK+ pts progression after CRZ (C-EXP-A1),progression after ≥1 2nd gen TKIs (C-EXP A2), ROS1+ progression after CRZ (C-EXP-B) and pts with ALK TKI naïve (C-EXP-C) were enrolled. Results: Up to Jan 13, 2023, 185 pts (median age 53 years, 45.9% male) were enrolled; Median treatment and follow-up was 5.5 and 6.7 months, respectively. There were no DLT observed and no MTD identified in D-ESCAL (5-125mg QD, n=19). Based on the safety, efficacy and PK exposure data of 42 pts in D-ESCAL and D-EXP, 60 mg QD was selected as the RP2D for C-EXP,the average AUCtau of 60mg QD reached to 5443ng*hr/mL. Treatment-related adverse events (TRAEs) occurred in 87.5% patients (162/185), the most common TRAEs were hypercholesterolemia (74.1%), hypertriglyceridemia (68.1%), weight gain (36.2%), peripheral edema (15.7%), peripheral neuropathy (14.1%). As for R2PD, 132 of 155 (85.2%) experienced TRAEs, Grade ≥3 TRAEs occurred in 19.7%, most frequent were hypertriglyceridemia (11%) and hypercholesterolemia (8.4% ). Dose interruptions and dose reductions associated with TRAEs were reported in 10 (5.4%) and 5 (2.7%) pts respectively. Confirmed response were observed in 142 ALK+pts enrolled in C-EXP, results are shown in the Table (Efficacy of B-ROS1+ pts will be reported separately). Eleven ALK mutations were detected in 16 pts (either alone or in combination); 50.0% pts achieved PR. Out of 6 pts who were positive for G1202R, 50.0% experienced PR. Conclusions: TGRX-326 was well tolerated in pts with advanced ALK+ NSCLC and showed promising clinical antitumor activity irrespectively of ALK+ resistance to CRZ and 2nd gen TKIs, especially among those with brain metastases. Impressive activity was seen in ALK TKI naïve NSCLC. TGRX-326 demonstrated antitumor activity against multiple ALK mutations including G1202R. Clinical trial information: NCT05441956 . [Table: see text]

Abstract 5158: Detection of EGFR mutations in plasma cfDNA and paired CTCs of NSCLC patients before and after osimertinib therapy using crystal digital PCR

Abstract Background: Circulating tumor DNA (ctDNA) analysis has clinical utility in EGFR mutantNSCLC. Circulating tumor cells (CTCs) constitute a unique source of information at thecellular level. Digital PCR (dPCR) is a valuable tool for accurate and valid mutation analysisin liquid biopsy. The aim of the current study was to detect EGFR mutations in plasma cfDNA and paired CTC-fractions of NSCLC patients before the initiation of osimertinib therapy and at progression of disease using crystal digital PCR (cdPCR). Patients and Methods: Forty-eight patients with EGFR mutated lung adenocarcinomas resistant to 1st or 2nd generation EGFR TKIs were treated with osimertinib in the context of a multicenter Phase II clinical study (NCT02771314). 2 mL of plasma were used for cfDNA extraction using the IDXtract kit (ID-Solutions, France). Crystal dPCR (naica® system, StillaTechnologies, France) was used to quantify mutation allele frequencies (MAF) of EGFRmutations in 91 cfDNA samples before and after osimertinib. 80 identical plasma samples were also analyzed with the FDA-approved cobas® technology. In parallel, EGFR mutations were detected with cdPCR in 64 matched CTC-fractions enriched by Parsortix™ (ANGLE plc, UK).Quality control steps were followed both at the preanalytical and analytical level. Results: Direct comparison between cdPCR and cobas® revealed high concordance rates forall EGFR mutations; however, in case of T790M, cdPCR proved to be more sensitive. Patients with higher %MAFs at PD presented significantly lower PFS compared to those with lower levels or without EGFR mutations. Direct comparison of EGFR genotyping between primary tissue and baseline plasma cfDNA samples revealed high concordance rates, too. During EGFR mutation analysis in paired CTC-derived gDNA, 11 samples were found positive for EGFR mutations with %MAF ranging from 0.2 to 2.25%. Conclusions: Crystal dPCR combines the unique benefits of sensitivity and accuracy with the multiplexing capacity for the detection of multiple EGFR mutations in plasma cfDNA samples and CTCs. High concordance rates were observed between cdPCR and cobas® assay. For the first time, cdPCR was applied to detect EGFR mutations in CTC-derived gDNA of NSCLC patients under osimertinib. Discordance between plasma and CTC-fractions might be indicative of tumor heterogeneity and predictive for acquired resistance. Acknowledgements-The research presented was carried out within the framework of a Stavros NiarchosFoundation grant to the National and Kapodistrian University of Athens-The authors would like to thank Larry Ba (Stilla Technologies, France) and Daniel Henaff(ID-solutions, France) for kindly providing the naica® digital PCR system and the ID-solutionskits, respectively. Citation Format: Aliki Ntzifa, Athanasios Kotsakis, Vassilis Georgoulias, Evi Lianidou. Detection of EGFR mutations in plasma cfDNA and paired CTCs of NSCLC patients before and after osimertinib therapy using crystal digital PCR [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5158.

EGFR-D770>GY and Other Rare EGFR Exon 20 Insertion Mutations with a G770 Equivalence Are Sensitive to Dacomitinib or Afatinib and Responsive to EGFR Exon 20 Insertion Mutant-Active Inhibitors in Preclinical Models and Clinical Scenarios.

Epidermal growth factor receptor (EGFR) exon 20 insertion mutations account for a tenth of all EGFR mutations in lung cancers. An important unmet clinical need is the identification of EGFR exon 20 insertion mutants that can respond to multiple classes of approved EGFR-TKIs. We sought to characterize variants involving EGFR-D770 to EGFR-G770 position equivalence changes that structurally allow for response to irreversible 2nd generation EGFR-TKIs. Our group used preclinical models of EGFR exon 20 insertion mutations to probe representative 1st (erlotinib), 2nd (afatinib, dacomitinib), 3rd generation (osimertinib) and EGFR exon 20 insertion mutant-active (poziotinib, mobocertinib) TKIs; we also queried the available clinical literature plus our institutional database to enumerate clinical outcomes. EGFR-D770>GY and other EGFR insertions with a G770 equivalence were identified at a frequency of 3.96% in separate cohorts of EGFR exon 20 insertion mutated lung cancer (n = 429). Cells driven by EGFR-D770>GY were insensitive to erlotinib and osimertinib, displayed sensitivity to poziotinib and dacomitinib and were uniquely sensitive to afatinib and dacomitinib in comparison with other more typical EGFR exon 20 insertion mutations using proliferation and biochemical assays. Clinical cases with EGFR-G770 equivalence from the literature and our center mirrored the preclinical data, with radiographic responses and clinical benefits restricted to afatinib, dacomitinib, poziotinib and mobocertinib, but not to erlotinib or osimertinib. Although they are rare, at <4% of all exon 20 insertion mutations, EGFR-G770 equivalence exon 20 insertion mutations are sensitive to approved 2nd generation EGFR TKIs and EGFR exon 20 insertion mutant-active TKIs (mobocertinib and poziotinib). EGFR-D770>GY and other insertions with a G770 equivalence join EGFR-A763_Y764insFQEA as exon 20 insertion mutationsresponsive to approved EGFR TKIs beyond mobocertinib; this data should be considered for clinical care, genomic profiling reports and clinical trial elaboration.

P47.12 ALKternate: A Proof of Concept Study in ALK-Rearranged NSCLC Alternating Lorlatinib With Crizotinib After Disease Progression

Standard frontline therapy for patients with advanced ALK-NSCLC has rapidly evolved to 2nd generation ALK TKIs based on superior survival. Regardless, resistance to treatment is inevitable. Most will receive multiple lines of TKIs +/- chemotherapy before eventually dying from the disease. Lorlatinib is a 3rd generation ALK TKI active against a broad range of acquired ALK kinase domain (KD) resistance mutations. A recent report demonstrated re-sensitization to crizotinib by the lorlatinib ALK resistance mutation L1198F.

MA02.07 T-DM1 and Osimertinib (TRAEMOS) To Target HER2 Bypass Track Resistance in EGFRm+ NSCLC: Interim Analysis of a Phase II Trial

Despite high response rates to osimertinib in patients with EGFR mutation positive (EGFRm+) NSCLC, resistance inevitably develops. HER2 overexpression and amplification is detected in 13% of NSCLC-patients with acquired TKI-resistance. Previously, we showed that trastuzumab and paclitaxel in this setting is associated with a 41% ORR. Here, we evaluated the efficacy and toxicity of trastuzumab-emtansine (T-DM1) and osimertinib in patients with HER2 overexpression and/or amplification after progression on osimertinib as last line of treatment. We report a pre-planned interim analysis. In this multicenter single arm phase II study with a safety run-in (NCT03784599), eligible patients (≥18 years, WHO PS ≤2) with EGFRm+ NSCLC, progressing on EGFR TKI treatment and with HER2 overexpression (IHC ≥2+ in ≥10% of the cells) and/or HER2 amplification (ISH and/or NGS) were included. Patients were treated with T-DM1 3.6 mg/kg (IV infusion) every 3 weeks and osimertinib 80 mg QD. For patients with progression on 1st or 2nd generation EGFR TKIs, osimertinib monotherapy was initiated and T-DM1 was added at time of progression on osimertinib. Primary endpoints were to assess the ORR after 12 weeks and to evaluate safety of the combination treatment. In the safety run in, assessed in a classical 3+3 design, the first 3 patients received T-DM1 3.0 mg/kg. If none of these 3 patients developed a dose limiting toxicity (DLT), the T-DM1 dose was escalated to the standard dose of 3.6 mg/kg. Responses were assessed every 6 weeks according to RECIST 1.1. Treatment was continued until progression or unacceptable toxicity. Sample size was calculated using Simon’s two stage minimax design (H0=41%, H1>55%, 80% power, one-sided type I error rate of 10%, sample size: 58 patients, cohort A ORR 16/36 in order to proceed to cohort B). From January 15 2019 until April 6 2021, 27 patients were included and started with T-DM1. In the safety run in, none of the patients developed a DLT. Therefore, the study continued with osimertinib 80 mg QD and T-DM1 3.6 mg/kg IV infusion q 3 weeks. ORR and DCR after 6 weeks of treatment, evaluable in 24 patients, was 0% and 63% (16/24) respectively. One patient is not yet evaluable for the primary endpoint. ORR and DCR after 12 weeks of treatment were 13% (3/23) and 43% (10/23). DCR in HER2 IHC2+ and 3+ cohort was 36% (5/14) and 55% (5/9). Median PFS was 2.8 months (95% CI, 2.3-3.3 months), median duration of disease control was 20 weeks (range 4-47 weeks). Grade 2/3 adverse events occurred in 29%/21% of patients, including pneumonitis, LVEF decrease, fatigue, erythema and CK elevation. There were no grade 4 and 5 therapy-related adverse events. TRAEMOS is the first trial combining T-DM1 and osimertinib in patients with EGFRm+ NSCLC and progression on osimertinib to target HER2 bypass track resistance. Safety profile is favorable compared to cytotoxic chemotherapy, however this treatment strategy showed very limited efficacy. Further clinical evaluation of this regimen is not warranted.

Totality outcome of afatinib sequential treatment in patients with EGFR mutation-positive NSCLC in Korea: KCSG LU-19-22.

9053 Background: While osimertinib showed impressive efficacy and safety profile in 1st-line setting for EGFR mutation-positive (EGFR M+) NSCLC patients, there are no standard targeted therapy following progression. Thus, interest has been growing on sequential treatment of osimertinib as 2nd-line treatment for patients acquiring T790M resistance mutation after 2nd generation EGFR TKIs. We did a retrospective study to support the hypothesis that sequential approach of afatinib followed by osimertinib represents a practical treatment option in ‘real-world’ practice. Methods: In this non-interventional, multicenter study, EGFR M+ NSCLC patients had to start 1st-line afatinib treatment ≥ 13 months prior to data entry. They were categorized into 4 cohorts according to 2nd-line treatments with retesting results: T790M+ patients sequentially treated with osimertinib in cohort A, T790M patients treated with chemotherapy or other treatments in cohort B, and patients with unknown mutation status in cohort C. Cohort D included patients who were still ongoing with afatinib. Primary outcome was the time on treatment (TOT) of patients receiving 1st-line afatinib (TOT-1) followed by 2nd-line treatments (TOT-2). Secondary endpoints were acquisition rate of T790M after progression, objective response rates of afatinib (ORR-1) and 2nd-line treatments (ORR-2), and overall survival (OS). Results: Among a total of 761 enrolled patients, 737 patients excluding 24 screening failures were allocated into cohort A (n=116), B (n=143), C (n=111), and D (n=367). Median age was 62 years (22 - 90) with 53.05% of female proportion. Brain metastasis was discovered in 38.94% at initial diagnosis. Regarding genotypes of EGFR mutations, del19 was 57.53%, 31.48% for L858R, 7.33% for uncommon mutations, and 3.66% for compound mutation. Median TOTs in cohort A, B, C, and D were 35.09 months (95% CI, 30.09 to 43.53), 18.76 months (95% CI, 16.92 to 20.20), 12.02 months (95% CI, 10.22 to 14.98), and 42.61 months (95% CI, 30.95 to 59.23), respectively. Particularly, in cohort A, median TOT-1 and TOT-2 were 17.43 months (95% CI, 15.21 to 19.32) and 11.04 months (95% CI, 7.10 to 14.13), respectively. Retesting was attempted in 262 of 370 patients (70.81%) with 44.27% of T790M detection rate. ORR-1 and -2 in cohort A, B, and C were 84.48% and 56.03%, 82.52% and 29.08%, 54.95% and 21.70%, respectively and 68.94% of ORR for cohort D. Median OS has was not reached. Conclusions: These data suggest that, in real-world practice, sequential afatinib followed by osimertinib be a feasible and effective therapeutic strategy for EGFR M+ NSCLC patients acquiring T790M during the period of afatinib treatment. Of note, median TOT in cohort D is over 3.5 years, suggesting that 1st-line afatinib potentially allow certain patients to maintain long-term, chemotherapy-free state. Further analysis is currently being undertaken and will be presented.

1195P The value of detecting resistance through liquid biopsy

Liquid biopsy has been established as an important diagnostic step in identifying EGFR T790M resistance to 1st and 2nd generation EGFR TKIs. This has led to significant interest in exploring the value of liquid biopsy in patients with other oncogene-addicted cancers and acquired resistance to targeted therapy.

Dasatinib overcomes stroma-based resistance to the FLT3 inhibitor quizartinib using multiple mechanisms.

FLT3-ITD mutations occur in 20–30% of AML patients and are associated with aggressive disease. Patients with relapsed FLT3-mutated disease respond well to 2nd generation FLT3 TKIs but inevitably relapse within a short timeframe. In this setting, until overt relapse occurs, the bone marrow microenvironment facilitates leukemia cell survival despite continued on-target inhibition. We demonstrate that human bone marrow derived conditioned medium (CM) protects FLT3-ITD+ AML cells from the 2nd generation FLT3 TKI quizartinib and activates STAT3 and STAT5 in leukemia cells. Extrinsic activation of STAT5 by CM is the primary mediator of leukemia cell resistance to FLT3 inhibition. Combination treatment with quizartinib and dasatinib abolishes STAT5 activation and significantly reduces the IC50 of quizartinib in FLT3-ITD+ AML cells cultured in CM. We demonstrate that CM protects FLT3-ITD+ AML cells from the inhibitory effects of quizartinib on glycolysis and that this is partially reversed by treating cells with the combination of quizartinib and dasatinib. Using a doxycycline-inducible STAT5 knockdown in the FLT3-ITD+ MOLM-13 cell line, we show that dasatinib-mediated suppression of leukemia cell glycolytic activity is STAT5-independent and provide a preclinical rationale for combination treatment with quizartinib and dasatinib in FLT3-ITD+ AML.

Next-generation sequencing based mutation profiling reveals heterogeneity of clinical response and resistance to osimertinib

ObjectivesThe 3rd generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR TKI) osimertinib has shown promising efficacy both in EGFR-mutant, T790M positive non-small cell lung cancer (NSCLC) patients who have become resistant to 1st or 2nd generation EGFR TKIs and patients with sensitizing EGFR mutations as the first line therapy. However, the degree and duration of response to osimertinib are heterogeneous. We hypothesized that the concurrent genomic landscape of these tumors could play a role in clinical outcomes and/or mechanisms of resistance. Materials and methodsWe conducted a retrospective multicenter study of lung cancer patients who had developed resistance to osimertinib. Genomic profiling was done for all the patients by using targeted next-generation sequencing encompassing 59–1021 cancer-related genes. Results and conclusionKnown EGFR-dependent resistant mutations and activation of alternative pathways were identified in 44 % of all the patients with great heterogeneity. Gain-of-function mutations of CTNNB1 were highly enriched in our cohort. Some other putative resistance mechanisms to osimertinib, such as the recurrent EGFR V834 L mutation, were also identified. Moreover, pathogenic mutations of TP53 were negatively related to the efficacy of osimertinib. To sum up, heterogeneity of resistance to osimertinib was not only manifested by inter-individual differences, but also embodied in its intra-individual diversity.

P2.03-42 Highly Sensitive Sel-CapTM Lung Cancer Panel NGS for Detection of Tumor-Derived EGFR Mutations in Plasma Cell-Free DNA in Lung Cancer

Next-generation sequencing is a genetic analysis platform for multiple analysis and large-scale analysis. Sensitivity is limited by methods for detecting cancer mutations that are contained at low rates in blood. With two highly sensitive detection techniques for genetic alterations, we evaluated their diagnostic value for tumor-derived EGFR mutations in plasma cell-free DNA (cfDNA) and measured concordance rate of activating EGFR mutations between cfDNA and tumor tissue. We conducted this study using FFPE tissue and plasma samples which were donated from NSCLC patients (N=316) between 2011 and 2013 and stored in the Human-derived Biomaterials Bank in Seoul St. Mary’s Hospital. Meanwhile, we prospectively collected plasma samples simultaneously when tumor tissue was taken out by surgery. We also collected peripheral blood just before administration of EGFR TKIs and each time imaging study was done during the administration of EGFR TKIs. We analyzed activating EGFR mutations in both cfDNA and tumor tissues using PNAclamping, Cancer panel and Sel-CapTM Lung Cancer Panel. The sensitivity and specificity of three detection techniques, PNAclamp, cancer panel and Sel-CapTM Lung Cancer Panel NGS for EGFR mutations in tumor tissues were more than 90% in all. In particular, EGFR T790M was found not only in the patients acquiring drug resistance approximately 10-12 months following the administration of 1st or 2nd generation EGFR TKIs, but also in the patients in whom EGFR TKI was continuously maintained over 30 months. The sensitivity of Sel-CapTM Lung Cancer Panel NGS for EGFR exon19 deletion and exon21 L858R in cfDNA was 76.2% and 61.1%, respectively. In addition, the sensitivity for double mutation of 19del and T790M was about 30% higher compared to that of cancer panel sold domestically (2/20, 10.0% vs. 9/20, 45.0%), suggesting that Sel-CapTM Lung Cancer Panel NGS enables to detect EGFR mutation up to 0.1% in plasma cfDNA. As a result of tracking of outcomes of EGFR TKIs treatment over time for patients with low frequency of EGFR mutations, we found that 1st or 2nd generation EGFR TKIs were switched into 3rd generation EGFR TKIs on the basis of disease progression on radiologic imaging, when an average of 6.8 months (0.2-25.4 months) elapsed from the first detection time of T790M in cfDNA. The presence of T790M in peripheral blood harvested periodically from patients receiving EGFR TKIs was initially identified about 3-5 months ahead of disease progress assessed by imaging study. With regard to the detection of EGFR mutations in lung cancer patients, Sel-CapTM Lung Cancer Panel NGS platform showed superior sensitivity to conventional NGS-based cancer panels as well as higher concordance rate between tumor tissues and plasma cfDNA. In longitudinal plasma cfDNA samples isolated from periodic liquid biopsies, quantitative changes of EGFR mutation were found to be significantly correlated to tumor response by EGFR TKIs. Our data suggest that Sel-CapTM Lung Cancer Panel NGS is a highly sensitive diagnostic platform for detection of EGFR T790M induced by long-term administration of EGFR TKIs and for determining when 3rd generation EGFR TKI be begun.

P2.01-11 ALKternate: A Proof of Concept Study in ALK-Rearranged NSCLC Alternating Lorlatinib with Crizotinib After Disease Progression

Standard frontline therapy for patients with advanced ALK-NSCLC has rapidly evolved to 2nd generation ALK TKIs based on superior survival. Regardless, resistance to treatment is inevitable. Most will receive multiple lines of TKIs ± chemotherapy before eventually dying from the disease. Lorlatinib is a 3rd generation ALK TKI active against a broad range of acquired ALK kinase domain (KD) resistance mutations. A recent report demonstrated re-sensitisation to crizotinib by the lorlatinib ALK resistance mutation L1198F. Increased knowledge of resistance mechanisms is key to overcoming and preventing its emergence. Based on knowledge of the varying patterns of resistance to different ALK TKIs, ALKternate will test the hypothesis that treatment with alternating TKIs will re-equilibrate the selection pressure for enrichment of resistant clones. This hypothesis has been tested preclinically in accompanying abstracts #2072 and #2074. ALKternate is a proof of concept open label multi-centre translational study alternating lorlatinib (100mg OD) with crizotinib (250mg BD) (Figure 1. including eligibility). The aim is to identify whether this fixed alternating schedule of ALK TKI is: safe; feasible and active, resulting in prolonged systemic and intracranial disease control via delaying the emergence of ALK TKI resistance. A secondary aim is to investigate whether plasma ALK-dependent and independent resistance profiles can be used to monitor therapy effectiveness. The primary outcome measure is time to treatment failure (TTTF) with alternating therapy. Secondary end points include best OR, PK analysis, PFS, DCR (systemic and CNS) after lorlatinib induction and the first cycle of alternating therapy, OS, toxicity, PROs and QOL measures. Plasma ctDNA and proteomic biomarkers will be analysed. Enrolled patients must demonstrate disease control after induction lorlatinib to continue alternating therapy. Imaging occurs more frequently initially (Figure 1.), before 12 weekly after two alternating cycles in those with disease control. Status: Trial in Progress. Enrollment began Q3 2019, ethics approval NSLHD ETH00389. Section not applicable Section not applicable

EP1.14-12 KRAS Exon 2 Mutation - A Resistance Pathway to 1st and 2nd Generation EGFR TKIs

EP1.14-12 KRAS Exon 2 Mutation - A Resistance Pathway to 1st and 2nd Generation EGFR TKIs

PB1925 COMPARATIVE STUDY OF GLIVEC VERSUS STATE SPONSORED GENERIC IMATINIB MESYLATE AS FIRST LINE THERAPY IN CHRONIC MYELOID LEUKEMIA‐ CHRONIC PHASE

Background:In a developing economy like India, Imatinib usage has increased manifold after generic formulations were introduced. 25 brands of generic Imatinib are approved by the Drug Controller General of India. The efficacy and safety of these brands have been repeatedly questioned by different studies. In most of these studies, generic Imatinib were used as a switch from the innovator. Institute of Hematology and Transfusion Medicine (IHTM) in Medical College, Kolkata is state run institute where two generic brands of Imatinib (Veenat; Natco, and Imatinate; KLabs) are available free of cost to the patients. Also there are patients who were on Glivec from the GiPAP and Max foundation at either free of cost or reduced cost. We took this opportunity to initiate a study to compare the efficacy and safety of these generic brands with the innovator brand (GIG vs IIG).Aims:1. To study the response rates, hematologic and non‐hematologic toxicities, tolerance, compliance and drop out rates of patients on generic Imatinib (GIG)2. To compare the above parameters in patients on innovator Imatinib (IIG)Methods:68 treatment naive CML‐CP patients who were started on generic Imatinib 400 mg/d from July 2015 to April 2016 were enrolled in the study. They were followed up for a median period of 30 months. The results were compared with 70 patients treated in our institute since Jan, 2014 on GiPAP program. Cytogenetic responses were assessed by FISH on bone marrow aspirates on 6 and 12months, and molecular responses were assessed by standardised qT‐ PCR on 3, 6, 12, and 18months of therapy to a resolution of 1 in 10‐4. Patients who were non‐compliant to therapy, response assessment and who failed hematologic response at 3 months were excluded from the analysisResults:Among the 60 patients of GIG included in the analysis, 43 were on Imatinate @KLabs and 17 were on Veenat @Natco. In GIG, 41.6% and 66.6% achieved complete cytogenetic response (CCyR) at 6 and 12 months as compared to 46.2% and 72.1% in IIG (p &gt; 0.05). The rates of optimum molecular responses (ELN 2013) in GIG at 3 and 6 months were 90% and 80% as compared to 92% and 86% in the IIG (p &gt; 0.05). However, the rates of MMR at 12 months in GIG and IIG were 63.3% and 71.4% respectively (p &lt; 0.05). The rates of failure of response by 18 months in GIG and IIG were 33.3% and 17.4% (p &lt; 0.05). In a median follow up of 30 months, 9 patients in GIG progressed to accelerated or blast phase and 20 patients were switched to 2nd line agents. In the IIG, 4 patients progressed and 12 patients were switched to 2nd line TKIs (p &lt; 0.05). There were 3 deaths in GIG and 2 in IIG. Grade 1/2 hematologic toxicities occurred in 100% patients in IIG as compared to 94% in GIG. Grade 3/4 hematologic toxicities occurred in 30% of IIG and 26% in GIG (p &gt; 0.05). Among the non‐hematologic toxicities, skin hypo‐pigmentation, gastritis, muscle cramps and arthritis were most common occurring in 58%, 50%, 30% and 24% in IIG and 50%, 44%, 32% and 30% in GIG. The rates of intolerance and therapy withdrawal are 10% in GIG as compared to 15% in IIG (p &gt; 0.05).Summary/Conclusion:When compared to the innovator brand (Glivec @Novartis), early cytogenetic and molecular responses in patients on generic Imatinib were similar. However, responses at 12 months, rates of failure of Imatinib, and progression of disease are significantly inferior in the GIG and more patients in GIG were switched to 2nd line TKI. Assessment of Deep molecular response rates might yield more significant results. The groups were similar in toxicity profile and therapy discontinuation

Early circulating tumor (ct)DNA dynamics and efficacy of lorlatinib in patients (pts) with advanced ALK-positive non-small cell lung cancer (NSCLC).

9019 Background: Lorlatinib is a selective, potent, brain-penetrant, 3rd generation (gen) ALK/ROS1 TKI approved for pts with advanced ALK+ NSCLC previously treated with a 2nd gen ALK TKI. We recently showed that ALK mutation tumor genotyping after failure of a 2nd gen ALK TKI may identify pts more likely to respond to lorlatinib.1 To identify other molecular response correlates, we evaluated if early ctDNA dynamics predict clinical outcome on lorlatinib. Methods: In pts enrolled on the ongoing ph 2 study (NCT01970865), plasma samples were prospectively collected for ctDNA analysis at baseline (BL), cycle 3 day 1 (C3D1, or 6 weeks) and end of treatment. Plasma DNA was analyzed using Guardant360. Change in variant allele fraction (dVAF)2 of ALK alterations (fusions and/or mutations) was calculated as (mean VAFC3D1) – (mean VAFBL); dVAF &lt; 0 indicated decreased ctDNA at C3D1. BOR, PFS and OS were evaluated according to dVAF. Results: Of 121 paired BL/C3D1 samples collected from 158 ALK+ pts previously treated with one or more 2nd gen ALK TKIs, 57 (47%) harbored a detectable ALK alteration at BL. At C3D1, mean VAF of ALK fusions and/or mutations was significantly decreased compared to BL (-1.07, p = 0.0014). Mean tumor volume was reduced by 26% in pts with dVAF &lt; 0 (n = 40), but only by 12% in pts with dVAF ≥0 (n = 13) (p = 0.049). Mean dVAF at C3D1 was significantly decreased compared to BL for pts with CR/PR, while there was no significant difference with SD or PD/IND; mean dVAF -1.84, -0.74, and +0.35 in pts with CR/PR, SD, or PD/IND, respectively (p = 0.0011, 0.1444 and 0.3383). Median PFS was 6.6 months (mo) in pts with dVAF &lt; 0 (n = 44) and 2.6 mo in pts with dVAF ≥0 (n = 13) (HR = 2.6, 95% CI: 1.2, 5.8). Median OS was 18.0 mo in pts with dVAF &lt; 0 (n = 34) and 8.6 mo in pts with dVAF ≥0 (n = 13) (HR 2.0, 95% CI, HR 0.9–4.6). Conclusions: Early ctDNA dynamics may predict lorlatinib efficacy in ALK+ NSCLC, with decreased ctDNA at 6 wks associated with better response and longer PFS. Further studies are needed to validate these findings and to determine whether early intervention based on dynamic ctDNA monitoring may improve outcome.

Abstract 4576: Combination of a label independent CTC enrichment platform with fluorescence in situ hybridization for the molecular characterization of CTCs in non-small cell lung cancer patients

Abstract Background: Patients with EGFRmt non-small cell lung cancer (NSCLC) develop resistance to first (erlotinib/ gefitinib) and second (afatinib) generation EGFR tyrosine kinase inhibitors (EGFR TKIs). Circulating tumor cells (CTCs) may be used as a potential biological material to monitor genetic alterations during the clinical course of the disease. We used the ParsortixTM (ANGLE) system, a label-independent microfluidic-based technology platform, to enrich CTCs from whole blood of NSCLC patients to evaluate the presence of HER-2 and c-MET amplification using fluorescence in situ hybridization (FISH). Materials and methods: Peripheral blood (PB) (15mL) from 42 patients with EGFRmt and resistant to 1st and 2nd generation EGFR TKIs NSCLC was obtained before, during and after treatment with osimertinib. CTCs were isolated using the ParsortixTM system and were further analyzed for HER-2 and c-MET amplification by FISH. Results: PB samples were obtained before (n=42), after one cycle (n=12) and at PD (n=7) during treatment with Osimertinib. One patient had HER-2 amplified CTCs whereas in total, 5 patients had marginally HER-2-positive CTCs; HER-2-positive CTCs were observed in 1/42 baseline sample but in none post-1st cycle and PD samples. Similarly, c-MET amplification was detected in 3/42 patients at baseline whereas in total 4 patients had marginally c-MET-positive CTCs. Treatment with Osimertinib resulted in a decrease of the number of c-MET amplified CTCs in these patients. In all c-MET and HER-2 amplified CTCs there was no HER-2 or c-MET amplification in the primary tumor. c-MET amplification in the primary tumor was detected only in one patient, however this patient had no detectable CTCs. Conclusions: Our preliminary results indicate that in selected patients with EGFRmt NSCLC, detection of HER-2 or c-MET amplified CTCs may be correlated with tumor resistance to EGFR TKIs. The ParsortixTM system can be successfully combined with downstream FISH analysis for the molecular characterization of CTCs in NSCLC patients. More samples are currently being analyzed in order to reveal the implication of HER-2 and c-MET amplification in resistance to therapy with first, second and third generation EGFR TKIs. Citation Format: Aliki Ntzifa, Martha Zavridou, Pavlos Pollakis, Georgia Bardi, Vasilis Georgoulias, Athanasios Kotsakis, Evi Lianidou. Combination of a label independent CTC enrichment platform with fluorescence in situ hybridization for the molecular characterization of CTCs in non-small cell lung cancer patients [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 4576.

Second Generation Tyrosisne Kinase Inhibitors As Upfront Therapy in the Era of Sleeve Gastrectomy Does It Work

Abstract Sleeve gastrectomy is a restrictive procedure. It greatly reduces the size of the stomach and limits the amount of food that can be eaten at one time. About 75% of the stomach is removed leaving a narrow gastric “tube” or “sleeve”. The effects of this kind of surgery in patients with chronic myeloid leukemia receiving tyrosine kinase inhibitors is not known Here we described the effects of sleeve gastrectomy in two patients underwent sleeve gastrectomy one underwent sleeve while on Dasatinib and the other started Nilotinib after sleeve gastrectomy both patients received TKI as upfront therapy. Case 1: A 34-year-old, morbidly obese woman was diagnosed with chronic myeloid leukemia. She had a low-risk Sokal score and was treated with Dasatinib 100 mg once daily as upfront therapy. The patient tolerated Dasatinib well, and she achieved a complete molecular response. 3 years later, the patient underwent a sleeve gastrectomy while receiving Dasatinib treatment ,weight decreased from 140 to 65 kg.She continued Dasatinib 100mg after sleeve but she lost her hematological response Testing for mutation analysis tends to be negative switched to Imatinib 400 mg with which she reachieved Hematologial remission and currently being followed as per ELN recommendations 2013 Case 2: A30 year old morbidly obese male underwent Gastric sleeve gastrectomy weight decreased from 120 kg to 52 kg two years later diagnosed with chronic myeloid leukemia with low risk Sokal Score started on Nilotinib 300 mg BID as upfront therapy .The patient tolerated Nilotinib well and he achieved complete hematological response but failed cytogentic and molecular response mutation analysis tends to be negative. Shifted to Imatinib where he achieved hematological, cytogentics and molecular response as per ELN recommendations 2013. Conclusion: overall it seems 2nd generations TKIs are not suitable as upfront therapy for patients with CML after sleeve gastrectomy Imatinib works better however further studies are needed to confirm these observations Disclosures No relevant conflicts of interest to declare.

Cost-Effectiveness Analysis (CEA) of Sequential Treatment with Tyrosine Kinase Inhibitors (TKIs) for Chronic Myelogenous Leukemia (CML)

Background: Imatinib has been approved for treatment of newly diagnosed CML since 2001. For patients failing imatinib, other treatment options such as dasatinib, nilotinib, bosutinib, and high-dose imatinib are recommended. Previous economic analyses assumed that patients are treated until progression, despite guidelines recommending changing treatments for non-responders. The objective was to perform a CEA of sequential treatment with 2nd line TKIs, from a commercial payer perspective in the United States (US).Methods: A Markov-cohort model was used to simulate lifetime treatment costs and health outcomes (discounted 3.0% per annum) for patients resistant or intolerant to 1st line imatinib. It compared six treatment sequences, starting from 2nd line (shown in the results table). The model included five health states: chronic phase 2nd line TKI, chronic phase 3rd line TKI, chronic phase no TKI, post-progression, and death. After 12 months of TKI treatment, patients without a major molecular or complete cytogenetic response (MMR or CCyR) moved to the next line of therapy (per NCCN guidelines). Patients could also move to the next treatment line if they lost MMR or CCyR, or discontinued due to drug-related toxicity. Data for response achievement, risks of progression, death, adverse events, and discontinuation were primarily based on data in published trials. Due to the lack of head-to-head studies for dasatinib vs. nilotinib in 2nd line, and a lack of time-to-response data for all three 2nd line treatments, MMR and CCyR rates were interpolated from available data points in 2nd line, while dasatinib and nilotinib rates were assumed to be equal in 3rd line. Dasatinib and imatinib progression, loss of response, and survival rates for 2nd line responders were assumed equal, due to data limitations. In each health state, patients accrued drug costs, resource use (related to monitoring, AE management, and disease management) costs and quality-adjusted life years (QALYs). Resource use, cost, and utility estimates were based on FDA labels, RedBook, Medicare and AHRQ Healthcare Cost Utilization Project data, and published economic analyses. Multi-way uncertainty analyses evaluated key contributors to uncertainty in the results, by testing various assumptions for probabilities of discontinuation, response, loss of response, progression, and survival.Results: The model predicts that 2nd line dasatinib provides increased survival (ΔLYs = ~0.4-2.6 years) and QALYs (ΔQALYs = ~0.4-2.8 years) in all patient groups when compared with 2nd line high-dose imatinib or nilotinib sequences. Also, 2nd line dasatinib was more costly (ΔLifetime Costs = ~$65,000 - $225,000) than high-dose imatinib and nilotinib, primarily due to longer survival and corresponding longer time on TKI treatment. In ±20% univariate sensitivity analyses, the model was most sensitive to 2nd line progression and survival estimates.Conclusions: This analysis suggests that dasatinib may be associated with increased life expectancy and quality of life when compared with high dose imatinib or nilotinib, among patients who are resistant or intolerant to 1st line imatinib, primarily based on higher cytogenetic response rates observed in studies of dasatinib. Other studies have shown improved quality of life for responders, and landmark analyses have shown improved survival for patients achieving cytogenetic response, but head-to-head clinical studies of sequential use of dasatinib and nilotinib are needed to confirm the model result. Based on the threshold of $150,000/QALY, dasatinib can be considered cost-effective in the US.Results Table:Sequence #Sequence 1Sequence 2Sequence 3Sequence 4Sequence 5Sequence 61st line(not modeled – assumes 1st line imatinib for all sequences)2nd lineDASNILHDIDASNILHDI3rd lineNILDASNILBOSBOSDASImatinib-resistant populationLYs76.54.57.36.84.5QALYs5.95.43.66.25.73.6Lifetime Cost$497,391$431,346$270,308$496,897$431,084$270,051ICERs: DAS followed by NIL vs. NIL followed by DAS - $129,139 DAS followed by NIL vs. HDI followed by NIL - $96,356Imatinib-intolerant populationLYs7.87.1–8.17.4–QALYs6.76.0–7.06.3–Lifetime Cost$599,270$509,456–$598,766$509,174–ICERs: DAS followed by NIL vs. NIL followed by DAS - $125,800BOS=bosutinib; DAS=dasatinib; HDI= high-dose imatinib; NIL=nilotinib; ICER=incremental cost-effectiveness ratio DisclosuresWhalen:Evidera, Inc.: Consultancy, Employment; Bristol-Myers Squibb: Research Funding. Stillman:Evidera, Inc.: Consultancy, Employment; Bristol-Myers Squibb: Research Funding. Ambavane:Evidera, Inc.: Consultancy, Employment; Bristol-Myers Squibb: Research Funding. Felber:Bristol-Myers Squibb: Employment, Equity Ownership. Makenbaeva:Bristol-Myers Squibb: Employment, Equity Ownership. Bolinder:Bristol-Myers Squibb: Employment, Equity Ownership.

Early Molecular Response in Chronic Myeloid Leukemia Patients Predicts Future Response Status

Objectives and background: The level of early MR is important for the optimization of therapy and making a decision to a switch to 2nd line therapy in patients (pts) who have not achieved an optimal response (OR). According to the recent recommendations at definition of OR on CML therapy, pts must have the level of BCR-ABL transcript gene at 10% or less and Ph-positive cells 35% or less at 3 months. But, in half of all cases of pts with BCR-ABL >10% at 3 months progression events happen between 3 and 6 months. The goal of our research was to investigate the prognostic impact of a large BCR-ABL transcript amount at 3 months on the subsequent response and the long-term outcome of CML pts treated frontline with IM.Methods: We have examined 185 pts, who have got IM from January 2010 up to the present. Molecular monitoring has been done regularly in all patients according to ELN recommendations. Median age was 49 years. All pts were in CP. BCR-ABL transcript levels were assessed by real-time quantitative PCR.Results: In our study 54% (100/185 cases) of pts achieved the optimal response with BCR-ABL transcript levels ≤10% at 3 months, 50,3% (93/185 cases) did it - with BCR-ABL transcript levels ≤1% at 6 months, and only 18% achieved the optimal response at 12 months. The comparative analysis has shown statistical differences in all characteristics in 2 groups of pts, who either achieved or not the optimal response at 3 months. Pts with BCR-ABL transcript levels ≤10% more often achieved CCgR at 6 months (g=0,0000), CCgR during all period (g=0,0004), MMR at 12 months (g=0,0000), MMR during all period (g=0,0012) and MR4 during all period (g=0,0000), pts had londer event-free (g=0,0432) and overall (g=0,0279) 4-year survival. [Display omitted] In our center we have switched 6 patients to the 2nd TKI - those who didn’t achieve the optimal response at 3 months. The switching showed the positive influence on loss level expression of BCR-ABL gene in 5 out of 6 patients. After that all patients achieved the optimal response in the future. For example, we had one patient with failure of IM at 3 months. We switched him the therapy to NI in 5 months after the diagnosis. As a result the patient achieved CCgR at 1,5 months, and the deep molecular response 4,5 log at 3 months.Conclusions: Early and deep responses to TKIs are predictive of long-term response and favorable survival outcomes. 3-month reduction in BCR-ABL transcript levels to >10% is a factor of bad effectiveness of TKI therapy and requires switching to the 2nd TKI. Timely switching to the 2nd TKIs allows us to achieve an optimal response in CML patients with level BCR-ABL >10% at 3 months.

High Frequencies Of Switching To 2nd TKIs and Failure To Maintain Standard Imatinib Dose In Japanese CML Patients With BIM Genetic Variants

Recently, it has been demonstrated that the proapoptotic protein BIM showed a deletion polymorphism at exon 3 in eastern Asian population, and some CML patients with the BIM deletion polymorphism are resistant to imatinib treatment (Ng et al. Nature Medicine, 2012). More recently, a BIM single nucleotide polymorphism (SNP) at exon 8 (c465C>T) has also been found in French CML patients and this SNP is associated with not only imatinib resistance but also the presence of BCR-ABL mutations (Mahon et al. ASH abstract, 2012).We aimed to investigate a possible association between such genetic variations of BIM and clinical manifestation in Japanese CML patients who experienced undetectable minimal residual disease (UMRD: so-called CMR4.5). In this study, we newly analyzed BIM SNP (c465C>T) in 47 CML-UMRD patients with known BIM deletion polymorphism status (Katagiri et al. Br J Haematol, 2013). Twenty normal subjects were used as controls.The frequency of either BIM SNP at exon 8 or BIM deletion polymorphism did not deviate from the normal subjects in the Japanese population (P = 0.7597 and P = 0.2880, respectively). None of the subjects showed both BIM SNP at exon 8 and BIM deletion polymorphism concomitantly. We then compared the clinical features among 3 CML-UMRD groups: patients with BIM SNP, patients with BIM deletion polymorphism, and patients who showed neither BIM SNP nor BIM deletion polymorphism (no genetic variations). The frequency of CML patients who maintained 400 mg imatinib dose until stopping was significantly higher in those without genetic variations than in those with BIM SNP or BIM deletion polymorphism (P = 0.0002). Moreover, the frequency of CML patients who switched to second tyrosine kinase inhibitors (2nd TKIs) was significantly higher in those with BIM SNP or BIM deletion polymorphism than in those without such polymorphisms (P = 0.0055).Number of CML patientsMaintained IM 400 mgChange of imatinib dose2nd TKIs switchingBIM SNP (c465C>T)11/474/115/112/11BIM deletion polymorphism6/471/63/62/6BIM SNP or deletion polymorphism17/475/178/174/17No BIM genetic variationss30/4725/305/300/30This is apparently the first study to circumstantiate the BIM genetic variants in Japanese CML patients with UMPD. Although the number of patients is small, our results suggest that CML patients without BIM deletion polymorphism/SNP could be maintained under standard imatinib dose without switching to 2nd TKIs, and thereby, have a possibility to stop TKIs therapy. Disclosures:Ohyashiki:Norvartis KK: Research Funding, Speakers Bureau; Bristol Meyer Squibe KK: Research Funding, Speakers Bureau.

Retention of Slow-Cycling CD34+ cells During Imatinib Treatment and Rapid Decline After 2nd ABL-TKI Treatment in Ph+ Leukemia Cells

Abstract 641▪▪This icon denotes a clinically relevant abstractSeveral mathematical models and ex-vivo examinations suggested that imatinib (IM) therapy does not eradicate BCR-ABL-positive leukemia stem cells (LSCs). We investigated 47 CML-chronic phase cases using methods previously reported (Jamieson et al., N Engl J Med, 2004. and Abe et al., Int J Hematol, 2008) with FACSAria™ and quantitative RT-PCR of BCR-ABL among each sorted population; total mononuclear cells, HSC/Thy-1+, HSC/Thy-1–, common myeloid progenitors (CMP), granulocyte macrophage progenitors (GMP) and megakaryocyte erythroid progenitors (MEP). In optimal responders to IM therapy, BCR-ABL transcripts in the HSC populations (HSC/Thy-1+ and HSC/Thy-1–) tended to be more retentive than other populations, while a gradual reduction was observed during the first 12 months in all populations. Moreover, the discrepancy of minimum residual diseases (MRD) between HSC and other populations became greater (about 2 log difference) in patients after longer IM therapy. We also prospectively investigated BCR-ABL transcripts in each population of 27 IM-resistant or -intolerant cases during treatment with the second-generation of ABL-tyrosine kinase inhibitors (2nd TKIs), dasatinib or nilotinib. Treatment with each inhibitor induced more rapid reduction of BCR-ABL transcripts even in the HSC population (CD34+CD38–) during the first 6 months for IM-intolerant cases, and there was no statistical difference of MRD among each population in optimal responders to 2nd TKI therapy. In order to examine mechanisms of Ph+ LSC resistance to IM, Ph+ ALL patient cells were serially xenotransplanted into immunodeficient NOD/SCID/IL2rγnull (NOG) mice and cells derived from leukemic NOG mice were then co-cultured with S17-stromal cells using previously reported methods (Minami et al., PNAS, 2008). Despite complete dephosphorylations of BCR-ABL and its substrate CrkL, slow-cycling (Hoechst-33342low/Pyronin-Ylow) CD34+ cells were insensitive to IM, which indicated that addiction of BCR-ABL activity is lower for survival in such quiescent cells. On the other hand, treatment with lower doses of 2nd TKIs induced not only growth inhibition but also substantial cell death including slow-cycling CD34+ population. More detailed biomarkers during pro-apoptotic status by 2nd TKI treatment are also under investigation. From comprehensive drug screening of small compounds in this co-culturing system, we also found several candidates involved with survival pathways in the cells. These results imply that 2nd TKI therapy can be a more promising approach than IM treatment for early reduction of Ph+ LSCs. Disclosures:Naoe:Kyowa-Hakko Kirin.: Research Funding; Dainipponn-Sumitomo Pharma.: Research Funding; Chugai Pharma.: Research Funding; Novartis Pharma.: Research Funding; Zenyaku-Kogyo: Research Funding; Otsuka Pharma.: Research Funding.