To Tyrosine Kinase Inhibitors Treatment Research Articles

Overcoming tyrosine kinase inhibitor resistance in lung cancer brain metastasis with CTLA4 blockade.

Lung cancer brain metastasis (LCBM) poses a significant clinical challenge due to acquired resistance to tyrosine kinase inhibitor (TKI) treatment. To elucidate its underlying mechanisms, we employed single-cell RNA sequencing analysis on surgically obtained LCBM samples with diverse genetic backgrounds and TKI treatment histories. Our study uncovers that TKI treatment elevates the immune checkpoint CTLA4 expression in Tcells, promoting an immune-suppressive microenvironment. This immunomodulation is initiated by tumor-derived HMGB1 in response to TKIs. In LCBM syngeneic murine models with TKI-sensitive or TKI-resistant EGFR mutations, combining CTLA4 blockade with TKIs demonstrates enhanced efficacy over TKI monotherapy or TKIs with PD1 blockade. These findings provide insights into the TKI resistance mechanisms and highlight the potential of CTLA4 blockade in effectively overcoming TKI resistance in LCBM.

Abstract A106: Disparities in the presence of driver mutations and response to tyrosine kinase inhibitors in young patients with lung cancer

Abstract Background: A concerning number of young patients (<50 years old) have been diagnosed with advanced lung cancer in recent years, likely due to driver mutations. This study examined disparities in the presence of driver mutations and response to tyrosine kinase inhibitors (TKI) in young patients with lung adenocarcinoma. Methods: This retrospective study included 98 patients (18-50 years old) with lung adenocarcinoma treated at the University of Miami Sylvester Comprehensive Cancer Center (2004-2023). Data from 81 patients with genetic information were analyzed. Patient demographics, clinical characteristics, and outcomes were collected. Chi- square and Kaplan-Meier methods were used, and p-values < 0.05 were considered significant. Results: Among the 17 patients without biomarker testing, 88% were white, 64.7% female and 59% Hispanic. The mean age at diagnosis for the 81 patients with genetic data was 41. Most were never smokers (56%), female (67%), white (83%), and Hispanic (52%) with stage IV disease (64%). At data cutoff in June 2023, 43 (53%) patients were alive, with a mOS of 27 months. Of the 81 patients, 58 (71.6%) had at least one driver mutation. The most common mutations were EGFR (31%), ALK (27%), and ROS1 (6%). No differences in mutation expression were found by gender, race, or ethnicity. Among patients with an actionable mutation, there were no significant differences in treatment with a TKI by race (p=0.337), gender (p=0.347), or ethnicity (p=0.940). However, 50% of eligible Black patients were not treated with a TKI compared to 26% of white patients. TKI as first-line treatment did not significantly vary by race (p=0.551), gender (p=0.883), or ethnicity (p=0.062), but 53% of white patients received a TKI as first-line therapy compared to 33% of Black patients. At data cutoff, there were no differences in the number of patients still taking a TKI based on gender (p=0.616), race (p=0.665), or ethnicity (p=0.465), although 46% of Hispanic patients were still on treatment compared to 35% of non-Hispanic patients. PFS on a TKI was similar for race (p=0.352) and gender (p=0.258), however Hispanic patients with an actionable mutation had a significantly longer PFS on a TKI than non-Hispanic patients (p=0.019), but not after controlling for age (p=0.116). Conclusion: This study is among the first to analyze disparities in driver mutations and response to targeted therapy in young patients with lung adenocarcinoma. No significant differences were found in TKI treatment, TKI as first-line therapy, or current TKI use by gender, race, or ethnicity. Notable trends included a greater percentage of eligible Black patients not receiving TKIs and fewer Black patients receiving TKIs as first-line therapy, although the sample of Black patients was small. Hispanic patients had a significantly longer PFS on TKIs than non-Hispanics, but not after controlling for age. Further research is needed to evaluate these trends, particularly with a larger cohort of Black patients. Citation Format: Kyle Edwards, Brandon Rose, Gilberto Lopes, Estelamari Rodriguez, Coral Olazagasti. Disparities in the presence of driver mutations and response to tyrosine kinase inhibitors in young patients with lung cancer [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A106.

T315I – a gatekeeper point mutation and its impact on the prognosis of chronic myeloid leukemia

Abstract Objectives BCR-ABL kinase domain mutations are an important cause of resistance to tyrosine kinase inhibitors (TKIs) in chronic myeloid leukaemia (CML) of which T315I is the most treatment-resilient. This study aimed to observe the frequency of T315I and its impact on disease prognosis in terms of progression and survival. Methods Patients with a response which categorized them into warning zone/or who failed to respond to their TKI treatment completely as per the European LeukemiaNet (ELN) were labeled as non-responders. They were assessed for T315I mutation using Amplification Refractory Mutation System-Polymerase Chain Reaction (ARMS-PCR) and validated via sequencing. Patients were then longitudinally followed for 96 months for the prognostic impact of the mutation. Results Of the 102 non-responders, T315I mutation was detected in 21.6 % of patients with a female preponderance. Almost 59 % of mutation-harbouring patients were labelled as low Sokal risk at baseline. The disease progression into the blastic phase was reported in 58.8 % of mutation-harbouring patients. Overall survival (study period: 96 months) was 81.8 % in patients harbouring T315I mutation. Patients in the blastic phase had significant odds of harbouring T315I mutation. Conclusions Sub-optimal response or failure to TKI treatment indicates the development of resistance due to the presence of T315I mutation or other mutation(s). Early identification will help redirect the patient’s treatment.

Single-cell proteo-transcriptomic profiling reveals altered characteristics of stem and progenitor cells in patients receiving cytoreductive hydroxyurea in early-phase chronic myeloid leukemia.

Hydroxyurea (HU) is frequently used in the early phase of chronic myeloid leukemia (CML) to achieve cytoreduction prior to tyrosine kinase inhibitor (TKI) therapy. However, its impact on CML stem and progenitor cells (SPC) remains largely unknown. This study utilized targeted proteo-transcriptomic expression data on 596 genes and 51 surface proteins in 60,000 CD14-CD34+ cells from chronic phase CML patients to determine effects of shortterm HU treatment (4-19 days) on CML SPC. Peripheral blood and bone marrow samples were obtained from 17 CML patients eligible for short-term HU treatment (three patients before and after HU; seven patients before HU; and seven patients after HU) and subjected to single-cell CITE-seq and/or flow cytometry analysis. The analysis revealed enhanced frequencies of hemoglobin-expressing (HBA1, HBA2, HBB) erythroid progenitor cells in blood and bone marrow following HU treatment. In addition, there was an accumulation of cell subsets with S/G2/M phase-related gene and protein expression, likely representing cells arrested in, or progressing slowly through, the cell cycle. The increased frequency of cells in S/G2/M phase after HU was observed already among the most immature leukemic stem cells (LSC), and patients with a high fraction of LSC in the S/G2/M phase showed poor responsiveness to TKI treatment. We conclude that short-term HU treatment entails differentiation of erythroid progenitor cells and alters the characteristics of LSC in CML. The results imply that studies of LSC and progenitor populations in CML should take effects of initial HU therapy into account.

Mutation analysis of BCR-ABL1 kinase domain in chronic myeloid leukemia patients with tyrosine kinase inhibitors resistance: a Malaysian cohort study

ObjectiveMutational analysis of BCR::ABL1 kinase domain (KD) is a crucial component of clinical decision algorithms for chronic myeloid leukemia (CML) patients with failure or warning responses to tyrosine kinase inhibitor (TKI) therapy. This study aimed to detect BCR::ABL1 KD mutations in CML patients with treatment resistance and assess the concordance between NGS (next generation sequencing) and Sanger sequencing (SS) in detecting these mutations.ResultsIn total, 12 different BCR::ABL1 KD mutations were identified by SS in 22.6% (19/84) of patients who were resistant to TKI treatment. Interestingly, NGS analysis of the same patient group revealed an additional four different BCR::ABL1 KD mutations in 27.4% (23/84) of patients. These mutations are M244V, A344V, E355A, and E459K with variant read frequency below 15%. No mutation was detected in 18 patients with optimal response to TKI therapy. Resistance to TKIs is associated with the acquisition of additional mutations in BCR::ABL1 KD after treatment with TKIs. Additionally, the use of NGS is advised for accurately determining the mutation status of BCR::ABL1 KD, particularly in cases where the allele frequency is low, and for identifying mutations across multiple exons simultaneously. Therefore, the utilization of NGS as a diagnostic platform for this test is very promising to guide therapeutic decision-making.

Abstract 2008: The N6-methyladenine-long noncoding RNA axis promotes drug resistance through PI3k signaling in leukemia

Abstract Disease recurrence characterized by drug resistance remains a major hurdle to the successful cancer treatment. Long noncoding RNAs (lncRNAs) and RNA N⁶-methyladenosine (m6A) have been linked to cancer recurrence. However, if and how lncRNAs and m6A coordinately determine drug resistance in tyrosine kinase (TK)-driven cancers are still unclear. We hypothesize that upon exposure to TK inhibitors (TKI), the dynamic m6A methylation epitransciptomically allows a set of proliferation/anti-apoptosis-relevant lncRNAs bearing m6A motifs to be rapidly upregulated, thus facilitating a subpopulation of cancer cells to evade TKI killing. By performing transcriptomic and epitransciptomic profiling in long-term TKI (nilotinib)-deprived leukemia resistant cells, we show that many differentially expressed lncRNAs enrich m6A, and more lncRNAs tend to have higher m6A content in resistant cells. We further demonstrate a broad clinical relevance of our findings, showing that upregulation of specific top-ranked lncRNAs (e.g., SENCR, PROX1-AS1, LN892) in TKI-resistant cell lines also occurs in leukemia patients at the diagnostic stage, blast crisis phase or in those not-responding to TKI treatment compared to chronic phase or TKI responders, respectively. Some of the upregulated lncRNAs in leukemia patients pre- and post-TKI treatment predict unfavorable outcomes and are associated with shorter survival duration. Through proliferative and clonogenic assays, we demonstrate that knockdown of SENCR, PROX1-AS1 or LN892 impairs resistant cell growth and renders resistant cells sensitive to nilotinib-induced cell death. We further found that this lncRNA upregulation is attributed to FTO-dependent m6A hypomethylation that stabilizes lncRNA transcripts. Using ectopic expression or genetic/pharmacological inhibition, we demonstrate that lncRNA upregulation empowers resistant cell growth through an activated PI3K signaling as supported by overexpression of PI3K signaling mediators (e.g., ITGA2, F2R, COL6A1). Treatment with PI3K inhibitor alpelisib sensitizes TKI-resistant cells to TKI-induced cell death and reduces leukemia burden in mice via downregulation of F2R, ITGA2, and COL6A1. In conclusion, our findings add a new layer to the complexity of mechanisms regulating leukemia cell fate under TKI selection and raise the possibility that the m6A-regulated lncRNAs represents a new non-genetic factor to affect the development and maintenance of TKI resistance; our discoveries identify a promising therapeutic target, the m6A-lncRNAs axis, for specifically the most challenging patient subpopulations who are TKI non-responders/relapsed but do not carry the acquired mutations on top of BCR/ABL; our results also uncover a strong predictor, m6A-regulated lncRNA-PI3K axis, for poorer prognosis and failure in drug response which might be a pan-cancer mechanism. Citation Format: Yanhong Tan, Changli Zhou, Sicheng Bian, Wencke Walter, Jiuxia Pang, Tao Cheng, Gang Huang, Gregor Hoermann, William Tse, Shujun Liu. The N6-methyladenine-long noncoding RNA axis promotes drug resistance through PI3k signaling in leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2008.

Clinical and molecular profiling of EGFR-mutant lung adenocarcinomas transformation to small cell lung cancer during TKI treatment.

Small cell lung cancer (SCLC) transformation serves as a significant mechanism of resistance to tyrosine kinase inhibitors (TKIs) in advanced non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. To address this clinical challenge, we conducted a retrospective analysis at Zhejiang University School of Medicine, the First Affiliated Hospital, focusing on patients with EGFR sensitizing mutations. A total of 1012 cases were included in this retrospective analysis. The cohort primarily consisted of patients with EGFR sensitizing mutations. Biopsy-confirmed small cell transformation was observed in seven patients, accounting for 0.7% of the cases. All patients in this subset were initially diagnosed with stage IV adenocarcinoma (ADC), with four cases classified as poorly differentiated and three as moderately to poorly differentiated ADC. EGFR exon 19 deletions were identified in five of these cases. Next-generation sequencing (NGS) was performed on seven cases, revealing mutations in the tumor protein p53 (TP53) gene in four cases and loss of the retinoblastoma1 (RB1) gene in three cases. The median duration from the initial diagnosis to small cell transformation was 35.9 months (interquartile range: 12.1-84 months). Following small cell transformation during EGFR inhibition, all patients received etoposide/platinum-based treatment, leading to a median progression-free survival (PFS) of 4.7 months (interquartile range: 2.7-10.1 months). Notably, most patients in this series had poorly differentiated adenocarcinomas at the outset. TP53 mutations and RB1 loss were common genetic alterations observed in patients with small cell transformation in this cohort. The findings underscore the clinical significance of SCLC transformation as a resistance mechanism to EGFR TKIs in NSCLC with EGFR mutations. The observed genetic alterations, including TP53 mutations and RB1 loss, suggest potential associations with the transformation process and warrant further investigation. Understanding the genetic landscape and clinical outcomes in patients experiencing small cell transformation can contribute to improved strategies for managing resistance in EGFR-mutant NSCLC.

Comparable b2a2/e13a2 and b3a2/e14a2 Reporting in BCR-ABL Assay When Calibrated By Who Is and By IVT-RNA Copy Number

Introduction: Xpert® BCR-ABL Ultra, automated cartridge-based assay for monitoring BCR-ABL transcript levels, is calibrated by WHO IS to standardize the %reporting for both b2a2/e13a2 BCR-ABL(e13a2) and b3a2/e14a2 BCR-ABL(e14a2) relative to control ABL gene in peripheral blood of patients as a standard management of Chronic Myeloid Leukemia (CML) [1]. Studies have shown differences in patients carrying e13a2 or e14a2 in molecular response to Tyrosine Kinase Inhibitor (TKI) treatment [2-4]. Therefore, it is necessary to understand if there is %reporting differences between two transcripts calibrated by WHO IS[5] and explore the calibration method using breakpoint specific RNA input copy number (CN) for accurate TKI treatment monitoring. Objectives: To establish % reporting method calculated with known CN of e13a2, e14a2 and ABL IVT-RNA within a wide CN range and compare % e13a2 and % e14a2 to WHO IS quantification system. Methods: Three IVT-RNAs, containing e13a2-ABL-BCR, e14a2-ABL-BCR and ABL-BCR, were synthesized as shown in Figure 1. Serial diluted e13a2 RNA, e14a2 RNA and ABL RNA panels were tested on Xpert BCR-ABL Ultra assay to generate individual standard curve of e13a2 Ct, e14a2 Ct and ABL Ct as a function of CN for % reporting calculation. Four levels of IVT-RNA panels with same CN of e13a2 and e14a2 were tested for breakpoint specific % reporting comparison. K562(e14a2), BV173 (e13a2) cell lysates and CML clinical samples carrying e13a2 or e14a2 transcripts were tested to evaluate the %CN reporting compared to WHO IS. Result: Good linearity demonstrated in Ct vs CN input for e13a2, e14a2 and ABL IVT-RNA (Figure2) with comparable efficiency (E) between e13a2 (E=0.992) and e14a2 (E=0.986). %e13a2 reporting was ~1.50-fold (by WHO IS) and ~1.46-fold (by %CN) higher than %e14a2, by testing IVT-RNA panel (Table1). Minor differences in %reporting observed between % CN and WHO IS for e13a2 (84.5%~110.8%) vs e14a2 (82.5%~89.5%) from cell lysates (Table2) and e13a2 (92.6%~105.5%) vs e14a2 (88.1%~92.2%) from clinical samples (Table3). Conclusions: A %CN e13a2/ABL and e14a2/ABL reporting method with known CN of IVT-RNAs has been successfully established in Xpert BCR-ABL Ultra. Both WHO IS and %CN showed very minor differences between e13a2 and e14a2 for % reporting. %CN method demonstrated comparable %reporting to WHO IS in Xpert BCR-ABL Ultra. Recent Publications 1. Dominy KM, Simon IM, Khorashad JS (2021) Evaluation of Xpert® BCR-ABL Ultra for the confirmation of BCR-ABL1 international scale conversion factors for the molecular monitoring of chronic myeloid leukaemia, Int J Lab Hematol, Feb;43(1):e31-e34. 2. Hanfstein B, Lauseker M, Hehlmann R, Saussele S, Erben P, Dietz C (2014) Distinct characteristics of e13a2 versus e14a2 BCR-ABL1 driven chronic myeloid leukemia under first-line therapy with imatinib. Haematologica.99:1441-7. 3. Jain P, Kantarjian H, Patel KP, Gonzalez GN, Luthra R, Shamanna RK (2016) Impact of BCR-ABL transcript type on outcome in patients with chronic-phase CML treated with tyrosine kinase inhibitors. Blood.127:1269-75. 4. Castagnetti F, Gugliotta G, Breccia M, Iurlo A, Levato L, Albano F (2017) The BCR-ABL1 transcript type influences response and outcome in Philadelphia chromosome-positive chronic myeloid leukemia patients treated frontline with imatinib. Am J Hematol. 92:797-805. 5. Matthew S, White HE, Hana Z, Nicholas C.P C (2022) Impact of BCR::ABL1 transcript type on RT-qPCR amplification performance and molecular response to therapy. Leukemia 36(7):1-8

Adherence to tyrosine kinase inhibitor and clinical outcomes in patients with chronic myeloid leukemia

PurposeTo ensure optimal care for patients with chronic myeloid leukemia (CML), adherence to tyrosine kinase inhibitors (TKIs) has emerged as a critical component. The objective of this study was to assess the impact of TKIs adherence on clinical outcomes in a cohort of Chinese CML patients who received treatment with TKIs. MethodsThis retrospective study employed a cross-sectional design utilizing questionnaires to assess adherence to TKIs in a sample of 398 patients diagnosed with CML. Adherence was measured using the Morisky Medication Adherence Scale (MMAS-8), which dichotomizes patients into low, medium, and high adherence groups. ResultsOf the patients included in this study, 34.2% were classified as highly adherent, with 43.2% and 22.6% of patients categorized as having medium and low adherence, respectively. Compared to the low-adherence group, patients in the medium- and high-adherence groups exhibited significantly higher rates of achieving major molecular response (MMR) and lower rates of switching TKIs. Moreover, patients who failed to adhere to TKIs treatment demonstrated significantly lower event-free survival and failure-free survival compared to those in the high-adherence group. Notably, regular molecular monitoring and utilization of the “CML Academy” mobile application were positively associated with increased TKI adherence. On the other hand, patients receiving third-generation or above first-line TKIs treatment displayed reduced adherence. ConclusionThe findings suggest that high adherence to TKIs treatment confers clinical benefits to patients with CML. Accordingly, the implementation of effective guidance and intervention measures aimed at promoting adherence to TKIs therapy in real-world settings is imperative.

How we monitor the therapy effectiveness in patients with chronic myeloid leukemia - A Single center experience

Chronic myeloid leukemia (CML) is a hematological disorder characterized by increased proliferation of the granulocytic cell lineage. We diagnose CML by presence of the breakpoint cluster region-abelson (BCR-ABL1) oncogene using the quantitative real-time polymerase chain reaction (QRT-PCR). This method provides an accurate and unambiguous follow-up of the treatment response to tyrosine kinase inhibitors (TKIs). This study aimed to determine the molecular response to the first and second generation of TKIs in first and second line of treatment using the QRT-PCR method. We conducted a retrospective study on 48 CML patients treated with the first and second generation of TKIs in first and second-line treatment. Treatment responses have been followed-up every 3 months using the QRT-PCR method. Patients were divided into three groups according to molecular responses to the first line of TKIs. Results obtained in this study showed that the first group of patients did not achieve major molecular response (MMR) in the first 18 months of TKI treatment. The second and third group of patients achieved MMR and deep molecular response (DMR) in the first 18 months of TKI treatment. These results indicate that patients with MMR and DMR in the first 18 months of TKIs treatment had a favourable clinical course of the disease. Inadequate molecular responses to the first line of TKIs can be improved with in increase of the dose of TKIs or by switching to other TKIs. Continuous and timely molecular monitoring of TKI’s response in CML patients provides a careful observation of the disease's course and a proper treatment approach.

Mutations in the MET tyrosine kinase domain and resistance to tyrosine kinase inhibitors in non-small-cell lung cancer

BackgroundThe Mesenchymal epithelial transition factor (MET) gene encodes a receptor tyrosine kinase with pleiotropic functions in cancer. MET exon 14 skipping alterations and high-level MET amplification are oncogenic and targetable genetic changes in patients with non-small-cell lung cancer (NSCLC). Resistance to tyrosine kinase inhibitors (TKIs) has been a major challenge for targeted therapies that impairs their clinical efficacies.MethodsEighty-six NSCLC patients were categorized into three cohorts based on the time of detecting MET tyrosine kinase domain (TKD) mutations (cohort 1: at baseline; cohort 2: after MET-TKI treatment; cohort 3: after EGFR-TKI treatment). Baseline and paired TKI treatment samples were analyzed by targeted next-generation sequencing.ResultsMET TKD mutations were highly prevalent in METex14-positive NSCLC patients after MET-TKI treatment, including L1195V, D1228N/H/Y/E, Y1230C/H/N/S, and a double-mutant within codons D1228 and M1229. Missense mutations in MET TKD were also identified at baseline and in post-EGFR-TKI treatment samples, which showed different distribution patterns than those in post-MET-TKI treatment samples. Remarkably, H1094Y and L1195F, absent from MET-TKI-treated patients, were the predominant type of MET TKD mutations in patients after EGFR-TKI treatment. D1228H, which was not found in treatment-naïve patients, also accounted for 14.3% of all MET TKD mutations in EGFR-TKI-treated samples. Two patients with baseline EGFR-sensitizing mutations who acquired MET-V1092I or MET-H1094Y after first-line EGFR-TKI treatment experienced an overall improvement in their clinical symptoms, followed by targeted therapy with MET-TKIs.ConclusionsMET TKD mutations were identified in both baseline and patients treated with TKIs. MET-H1094Y might play an oncogenic role in NSCLC and may confer acquired resistance to EGFR-TKIs. Preliminary data indicates that EGFR-mutated NSCLC patients who acquired MET-V1092I or MET-H1094Y may benefit from combinatorial therapy with EGFR-TKI and MET-TKI, providing insights into personalized medical treatment.

Single-cell transcriptional profiling uncovers the association between EOMES+CD8+ T cells and acquired EGFR-TKI resistance.

Acquired resistance to tyrosine kinase inhibitors (TKIs) is reportedly inevitable in lung cancers harboring epidermal growth factor receptor (EGFR) mutations, emphasizing the need for novel approaches to predict EGFR-TKI resistance for clinical monitoring and patient management. This study identified a significant increase in eomesodermin (EOMES)+CD8+ T cells in the TKI-resistant patients, which was correlated with poor survival. The increase in EOMES+CD8+ T cells was further confirmed in both tissue samples and peripheral blood of patients with TKIs resistance. The integrated analysis of pseudotime and Gene set variation showed that the increase in EOMES+CD8+ T cells may be attributed to TRM T cell conversion and metabolic reprogramming. Overall, this work suggested an association between the increased number of EOMES+CD8+ T cells and acquired TKI drug resistance, supporting the utility of EOMES+CD8+ T cells as a biomarker for TKI treatment response.

Kinase Domain Mutation Testing and Clinical Outcome in a Nationwide Chronic Myeloid Leukemia Patient Population

Background: ABL1 kinase domain mutations (KDM) are associated with resistance to tyrosine kinase inhibitors (TKI) and inferior outcome in chronic myeloid leukemia (CML) patients. Current guidelines recommend KDM testing in case of failure or resistance during TKI treatment. In this analysis, we aimed to assess (1) the clinical practice of KDM testing in the Netherlands, (2) the observed responses to subsequent TKI in the presence of a KDM in relation to the in vitro half-maximal inhibitory concentration (IC50)-values, and (3) the clinical outcome of patients for whom KDM testing was done. Methods: Data were obtained from a nationwide population based CML registry (Pharos-HemoBase) and six CML-reference centers in the Netherlands. We included adult Ph+ CML patients who were treated with a TKI and who had at least one KDM analysis after December 2005, when second generation TKI became available in the Netherlands. Reasons for KDM testing were categorized in three main groups based on the pattern of TKI failure: (1) primary resistance (no response), (2) suboptimal response and (3) loss of response. A suboptimal response was defined as failure to achieve the ELN response milestones, but with the achievement of at least 1-log BCR::ABL1 reduction. Loss of response was defined as losing a previously achieved ELN response milestone. A cox regression model was used for the survival analysis. Results: A total of 391 KDM analyses performed in 275 patients between December 2015 and March 2022 were included. When focusing on CP CML, most KDM analyses were performed because of a suboptimal TKI response (n=155), however in only nine (6%) a KDM was detected. In patients with primary TKI resistance, a KDM was detected in 17 of 81 analyses (21%). The highest yield of KDM was in patients losing a previously achieved response with 43 of 89 (49%) of analyses showing a mutation. Twenty-five KDM analyses were performed outside the context of TKI failure (e.g. BCR::ABL1 fluctuations but no loss of MMR, molecular relapse after a TFR attempt) and in none of them a mutation was detected. In total, 84 KDM were detected (panel A). Sixty-nine (25%) patients harbored at least one KDM of whom 24 the T315I mutation and eight a compound mutation. Most KDM analyses were done with Sanger Sequencing (SS). Fifty-four TKI treatment lines were assessable for response for patients who harbored a KDM with known in vitro IC50-values for predicted effectiveness of TKI. Of the patients who were treated with a TKI with a good predicted response, 34 of 42 (81%) indeed obtained a durable major molecular response, while seven patients experienced failure (4 no response, 3 loss of response). In patients who were treated with a TKI for which intermediate sensitivity was predicted, 4 of 6 (67%) responded well. In patients who were treated with a TKI for which resistance was predicted, only 3 of 6 (50%) responded. Progression to advanced stage disease (AP/BC), hematopoietic stem cell transplantation (HSCT) and death occurred more often in patients with a KDM compared to patients without a KDM: AP/BC in 25 (36%) versus 29 (14%) patients, HSCT in 20 (29%) versus 43 (21%), death in 26 (38%) versus 29 (14%) and CML-related death in 12 (17%) versus 10 (5%), respectively. Ten-year overall survival (OS) after the first KDM analysis was 49% versus 82% in patients with versus without a KDM, respectively, with a median follow-up of 7.2 years (panel B). The HR of harboring a KDM for OS was 0.355 (95% CI, 0.209-0.603; p<0.001). After correction for age, sex, disease phase and Sokal score, the HR was 0.356 (95% CI, 0.182-0.696; p=0.003). Discussion: This is the first study describing the nationwide practice of KDM testing and assessing the clinical outcome of patients with a KDM in relation to IC50-values. More than 70% of the KDM were detected in patients with primary TKI resistance or in patients who lost a previously achieved response. Observed responses to TKI after the detection of a KDM were mainly in accordance with expected responses based on the IC-value, supporting the use of these in vitro derived predictions in clinical practice. In line with previous studies, the presence of a KDM translated in inferior outcomes with higher prevalence of progressive disease and (CML-related) death. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Real-World Management of Chronic Myeloid Leukemia in Bosnia and Herzegovina: Treatment Patterns, Molecular Monitoring, and Outcomes

Introduction Chronic myeloid leukemia (CML) patients in low- and middle-income countries have limited access to tyrosine kinase inhibitor (TKI) therapies. Long delays in the start of TKI treatment may have significant consequences on patients' outcomes; therefore, monitoring and therapy management of these patients is undoubtedly challenging. The aim of the study was to conduct a comprehensive long-term analysis of CML management in a developing country in the era of limited TKIs. Methods Newly diagnosed CML patients in chronic phase (n=265) treated with imatinib (Glivec or generics) or nilotinib (Tasigna) in the period from 6/2005 to 6/2022 in the Federation of Bosnia and Herzegovina were included in this multicenter study. Glivec was available from 6/2005 to 9/2013, generic imatinib from 9/2013 to present, and Tasigna from 11/2011 to present. From 2005 to 2013, the waiting list was created due to the limited number of TKIs. Introduction of generic imatinib in 9/2013 led to the cancellation of the waiting list; branded imatinib was ceased and patients were switched to generics. Patient cohort consisted of 171 patients started on front-line imatinib, 60 patients on front-line nilotinib, 19 patients who died while waiting for TKI, 7 patients who discontinued therapy (pregnancy (n=3) or voluntarily (n=4)), and 8 patients did not have complete data. Patients were categorized based on the type of therapy: Group 1 (front-line imatinib, n=171) and Group 2 (front-line nilotinib, n=60). In Group 1, patients were furthermore subcategorized: Group 1a (front-line Glivec, n=83) and Group 1b (front-line generic imatinib, n=88). Patients from Group 1 and Group 2 were additionally categorized and compared according the length of wait period before therapy initiation: <6 months wait (n=120 vs. n=43), 6-12 months wait (n=20 vs. n=7), and >13 months wait (n=31 vs. n=10). BCR-ABL1 was confirmed by nested PCR/FISH/karyotype and BCR-ABL1 QPCR was evaluated every three months from 2012. Complete cytogenetic response (CCyR) was defined as <1% BCR-ABL1-positive nuclei of at least 200 nuclei by FISH or 20 metaphases using CBA. Major molecular response (MMR) was defined as ≤0.1% BCR-ABL1 expression. Standard patients' variables were collected and survival probabilities were estimated using the Kaplan-Meier method and compared with the log-rank test. The study was conducted according to the Declaration of Helsinki. Results We compared overall survival (OS), CCyR, and MMR in 265 patients based on the type of therapy (branded or generic imatinib and nilotinib) and delayed treatment. We first compared outcomes of patients based on initiating therapy alone, imatinib (Group 1, 42 months median follow-up) and nilotinib (Group 2, 45 months median follow-up). In Group 1, 39% (n=66) of patients were switched to nilotinib. In Group 2, 7% (n=4) were switched to imatinib. In Group 1, 27 patients died on front-line imatinib, 14 patients on second-line nilotinib, and one on third-line imatinib (overall 25%); in Group 2, 6 patients died on front-line nilotinib, and 1 on second-line imatinib (overall 12%). At 120 months, OS was 69% vs. 81% for Group 1 and Group 2, respectively (p=0.057); CCyR at 36 months was 73% vs. 89%, respectively (p=0.000); MMR at 36 months was 69% vs. 88%, respectively (p=0.000). Comparing the outcomes of branded (Group 1a) vs. generic imatinib (Group 1b), we found that at 72 months, OS, CCyR, and MMR were not significantly different (85% vs. 84%, p=0.876; 90% vs. 90%, p=0.051; 88% vs. 92%, p=0.11, respectively). Among imatinib treated patients, subgroups <6 months wait, 6-12 months wait, and >13 months wait showed deleterious effects on long-term patients outcomes; OS at 120 months was 78%, 76%, and 42% (p=0.040), CCyR at 48 months was 90%, 87%, and 58% (p=0.000), MMR at 60 months was 87%, 65%, and 44% (p=0.000), and MR4 at 60 months was 74%, 42%, and 37% (p=0.020). However, patients treated with nilotinib after the delay showed no significant differences in OS, CCyR, and MMR compared to immediate nilotinib treatment. Conclusion The long-term study from Bosnia showed that OS, cytogenetic, and molecular reponses were similar to previously published real-world data. Outcomes on generic imatinib were comparable to branded imatinib. However, nilotinib showed superiority over imatinib, especially in patients whose start of treatment was delayed.

67P Distinct concomitant genetic alterations in EGFR-mutant non-small cell lung cancer patients with brain metastases

EGFR-mutant NSCLC with brain metastases displays diverse trajectories to tyrosine kinase inhibitor (TKI) treatment. Exploring concomitant genetic alterations might describe the underlying mechanisms and identify different subsets of patients. From Jan 2013 to Dec 2020, NSCLC patients with brain metastases were screened and patients harboring EGFR mutation enrolled. Clinical data of patients with next-generation sequencing (NGS) data were then analyzed. Kaplan-Meier method and the Cox proportional hazards model were used for survival analysis. Based on the multivariable analysis, a nomogram was constructed using R version 4.0.5. A total of 2657 NSCLC patients with brain metastases were screened and 737 harboring EGFR mutation, among 73 patients with NGS data, all receiving EGFR TKI treatment, the median age was 58.1years, 35(47.9%) were male, 35(47.9%) were EGFR 19Del. Median overall survival (OS) were 23.6 months. Fifty-five patients (75.3%) harbored concomitant alterations, with TP53 (45.2%), EGFR amplification (12.3%) and RB1(9.6%) being the top three most frequently alterations. Concomitant genetic alterations were significantly associated with reduced OS(23.2 months vs NR, P=0.016). Especially, TP53 mutation (HR=1.8, 95%CI:1.0-3.2) and EGFR amplification (HR=2.5, 95%CI:1.2-5.6) were associated with significantly worse OS. Among the patients with driver genes(HR= 8.0, 95%CI:2.0-31.1) or tumor suppressor genes(HR= 10.6, 95%CI:1.8-60.2) had significantly worse OS than patients without concomitant alterations. However, OS was comparable for patients with local surgical or radiotherapy. As shown in the nomogram, a higher total score was associated with having EGFR 19del mutations and without concomitant alterations indicated a higher likelihood of longer OS. This study reveals the widespread existence of concomitant alterations in patients with EGFR-mutant NSCLC with brain metastases. Concomitant alterations were associated with the poorer clinical outcomes of patients. Based on the nomogram, we identified that the subset of patients without concomitant alterations and EGFR 19Del could derive more survival benefit from the EGFR-TKI treatment.

Immunological effect of tyrosine kinase inhibitors on the tumor immune environment in non-small cell lung cancer.

Acquired resistance to tyrosine kinase inhibitors (TKIs) limits the duration of antitumor effects and impairs the survival of patients with oncogene-driven non-small cell lung cancer (NSCLC). At present, little is known about the immunomodulatory ability of TKIs during the entire treatment period, including the drug-sensitive and drug-resistant periods. The present review aimed to comprehensively explore the dynamic changes in the tumor microenvironment (TME) during TKI treatment in NSCLC. Previous clinical and preclinical studies from medical and health databases related to NSCLC are reviewed. During the response period, cytotoxic immune cells accumulate in the TME and contribute to the formation of an inflammatory microenvironment. During the resistance period, the number of immunosuppressive cells increases, as does the expression of immune checkpoint proteins, which are critical mechanisms for tumor progression. The combination of targeted therapy and immunotherapy has been explored in multiple studies, and preliminary data showed controversial results. Extensive studies are needed to confirm the criteria of the selected patient subgroups and the toxicity profiles of EGFR TKIs and immune checkpoint inhibitors (ICIs). At present, the reagents targeting other immune cells, cytokines and related pathways remain underexplored compared with the revolutionary effect of ICIs in lung cancer. In the future, the precisely selected regimens for combination treatment should be further investigated in carefully designed xenograft models and clinical trials.

The association of genetic alterations with response rate in newly diagnosed chronic myeloid leukemia patients

Genetic differences may be associated with the response to tyrosine kinase inhibitor (TKI) in patients with chronic myeloid leukemia (CML). In this study, we identified genetic alterations between rapid and slow responders (BCR/ABL1 International Scale at 6 months: ≤0.1 % vs. > 0.1 %) of TKI treatment in chronic phase CML patients. Our analyses involved single nucleotide polymorphism (SNP), a Genome Wide Association Study and a Network-wide Association Study (NetWAS). Seventy-two patients from 16 institutions were enrolled and treated with a TKI, nilotinib. Gene Set Analysis identified genetic alterations in pathways related to the differentiation, proliferation, and activity of various innate immune cells. The NetWAS analysis found that genes associated with natural killer (NK) cells (PTPRCAP, BLNK, HCK, ARHGEF11, GPR183, TRPV2, SHKBP1, CD2) showed significant differences between rapid and slow responders of nilotinib. However, we found no significantly different genetic alterations according to the response in the SNP analysis. In conclusion, we found that rapidity of response to TKI was associated with pathway-associated genetic alterations in immune cells, particularly with respect to NK cell activity. These results suggested that the innate immune system at initial diagnosis had an important role in treatment response in patients with CML.

Molecular subtypes of small cell lung cancer transformed from adenocarcinoma after EGFR tyrosine kinase inhibitor treatment.

BackgroundA certain proportion of non-small cell lung cancer (NSCLC) with activating EGFR mutations showed resistance to tyrosine kinase inhibitors (TKIs) by transforming their histology into small cell lung cancer (SCLC). In this study, we evaluated the molecular characteristics of transformed SCLCs.MethodsEighteen SCLC tissue samples transformed after EGFR TKI treatment were used for the analysis. Immunohistochemistry was conducted to evaluate the molecular subtype using antibodies representative of the major transcriptional factor-based molecular subtypes, ASCL1 (SCLC-A), NEUROD1 (SCLC-N), POU2F3 (SCLC-P), and YAP1. Subtypes were categorized based on a predefined criteria.ResultsAmong the study population (n=18), most of the patients were initially diagnosed with adenocarcinoma (n=17), and one patient was diagnosed with adenosquamous histology. Eight patients (44.4%) were never-smokers, and nine patients were women (50.0%). Staining of pre-transformation sample was conducted in six patients, and five of them showed no discernible expression for ASCL1, NEUROD1, or POU2F3. However, the proportion of molecular subtypes after SCLC transformation was predominantly SCLC-N (n=9, 50.0%), followed by SCLC-Triple Negative (SCLC-TN; n=5, 27.8%) and SCLC-A (n=4, 22.2%). The median overall survival from TKI initiation was longer in patients who transformed to SCLC-A (P=0.009) than in those who transformed to either SCLC-N or SCLC-TN. However, the overall survival difference since SCLC transformation was not significant (P=0.370).ConclusionsIn our series, SCLC-N subtype was prevalent in SCLC transformed after EGFR TKI treatment. In addition, overall survival and the time to SCLC transformation from the EGFR TKI treatment were longer in patients who transformed to the SCLC-A type. Large-scale data will be required to confirm our findings.

Comparative clinical outcomes for patients with advanced NSCLC harboring EGFR exon 20 insertion mutations and common EGFR mutations

IntroductionReal-world clinical outcomes in patients with advanced NSCLC harboring EGFR exon 20 insertion (exon20ins) mutations have not been extensively studied. We conducted a retrospective cohort study to assess the clinical outcomes of EGFR exon20ins compared with common EGFR (cEGFR) mutations. MethodsAdults with advanced NSCLC harboring any EGFR mutations in the NSCLC Flatiron registry (2011 through May 2020) were included. To compare the relative prognosis (prognostic value) of exon20ins vs cEGFR, real-world overall survival (rwOS) was the primary endpoint. Separately, to compare the relative response to tyrosine kinase inhibitor (TKI) treatment (predictive value), real-world progression-free survival (rwPFS) was the primary endpoint. ResultsFor the prognostic value analysis, 3014 patients with EGFR mutant NSCLC (cEGFR, n = 2833; EGFR exon20ins, n = 181) were eligible. The median (95% CI) rwOS was 16.2 (11.04–19.38) months in the EGFR exon20ins cohort vs 25.5 (24.48–27.04) months in the cEGFR cohort (adjusted HR, 1.75 [1.45–2.13]; p < 0.0001); 5-year rwOS was 8% and 19%, respectively. For the predictive value analysis, 2825 patients received TKI treatment and were eligible (cEGFR, n = 2749; EGFR exon20ins, n = 76). The median (95% CI) rwPFS from start of the first TKI was 2.9 (2.14–3.91) months in the EGFR exon20ins cohort vs 10.5 (10.05–10.94) months in the cEGFR cohort (adjusted HR, 2.69 [2.05–3.54]; p < 0001). Among patients with EGFR exon20ins, the most common prescribed first-line therapy was platinum-based chemotherapy (61.3%) followed by EGFR TKIs (21.5%); second-line treatments were varied, with no clear standard of care. ConclusionsPatients with EGFR exon20ins have poor prognosis and receive little benefit from EGFR TKI treatment. More effective therapies are needed in this difficult-to-treat population.

Treatment Free Survival (TFS) in Patients (pts) with Chronic Myeloid Leukemia (CML) Carrying Atypical BCR-ABL1 Fusion Transcripts: The French CML Group (Fi-LMC) Experience

▪AimsLife expectancy of CML pts optimally responding to tyrosine kinase inhibitors (TKI) is close to that of the general population and recently, TFR has been acknowledged as a new goal of CML management. TKI discontinuation in the view of TFR requires the achievement of deep and long-lasting molecular responses (MR). The gold standard BCR-ABL mRNA quantification technology and MR definitions rely on internationally standardized (IS) RT-qPCR but atypical transcripts located outside the Major-BCR region, harbored by 1-2% of pts, cannot be expressed on the IS scale. Thus, most trials and clinical practice recommendations prevent such pts from attempting TFR. The Fi-LMC group retrospectively collected real-life observations to assess TFR likelihood in this rare population.MethodsData from CML pts with precise characterization of atypical transcripts in whom any line TKI was stopped for any reason but after at least 2 years of undetectable molecular residual disease (UMRD) by individualized non-standardized RT-qPCR were collected. RT-qPCR sensitivity varied depending on transcript type and local molecular biology laboratory. TFS was estimated by the Kaplan-Meier method. Relapse was analyzed using the cumulative incidence function, relapse being as UMRD loss at any time and any level during follow-up (FU).ResultsOur series comprised 16 adult CP CML pts with atypical BCR-ABL fusions including 12 males (75%). Median age at CML diagnosis was 56 years (range: 21-75) and that at TKI discontinuation was 67 years [range: 29-82]. Sokal score was low, intermediate and high in 7, 8 and 1 pts, respectively. ELTS score was low and intermediate in 10 and 4 pts, respectively and unknown in 2. Most pts expressed e19a2 (n=6) followed by e6a2 (n=4), b3a3 (n=3), b2a3 (n=2) and e8a2 (n=1). Seven pts discontinued imatinib, 4 stopped dasatinib, 4 nilotinib and 1 bosutinib. Number of lines of therapy was 2 in 8 pts, 1 in 5 pts and 3 in 3 pts. Median TKI treatment duration before discontinuation was 64 months (range: 31-218) and median duration of UMRD was 41 months (range: 21-168). The median FU after TKI discontinuation was 68 months (range: 3-149). Five pts experienced relapse leading to TKI resumption. Four relapses occurred within 3-6 months and included 2 loss of hematologic response in CP, 1 loss of hematologic response in accelerated phase CML and 1 molecular recurrence with BCR-ABL transcripts up to 1.5%. One relapse occurred at 49 months and consisted in loss of a complete cytogenetic response. These 5 pts resumed TKI and regained UMRD within 6 months, including 1 pt who died in UMRD from non-CML-related cause at the age of 82 years and 1 pt who rapidly failed a 2 nd TKI discontinuation attempt.In 1 additional pt, BCR-ABL transcripts became detectable intermittently with maximum transcript level of 0.15% and TKI was not resumed. The median FU of pts who remained treatment-free was 68 months (range: 8-149).Overall, the 5-year cumulative incidence of relapse regardless of whether TKI was resumed was 41.6% (95% confidence interval: 21.9%-78.7%) (Figure 1). The 5-year TFS rate was 65.2% (95% confidence interval: 40.3%-90.2%) (Figure 2).ConclusionsOur observational study of TKI discontinuation in CML pts with atypical BCR-ABL transcripts is the largest reported so far. While effort must be made for proper assessment of deep MR, preliminary results suggest that TFS pattern might favorably compare with that obtained in pts with Major-type BCR-ABL transcripts. However, relapses may be more aggressive and caution is required in order to avoid loss of hematologic responses and progression. Whether the type of atypical fusion gene influences TKI discontinuation outcome, as well as other potential prognostic factors, need to be determined in a larger series. [Display omitted] DisclosuresCharbonnier: Novartis: Speakers Bureau; Incyte: Speakers Bureau. Rea: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Etienne: Novartis: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau. Rousselot: Incyte, Pfizer: Consultancy, Research Funding. Nicolini: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel, accommodations, expenses, Research Funding; Kartos Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sun Pharma Ltd.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Incyte Biosciences: Honoraria, Other: travel, accommodations, expenses, Research Funding, Speakers Bureau; BMS: Honoraria.