Generation Tyrosine Kinase Inhibitors Research Articles

Cardiovascular events in CML patients treated with nilotinib: validation of the HFA-ICOS baseline risk score

Abstract Background The therapeutic landscape of chronic myeloid leukaemia (CML) has been transformed by tyrosine kinase inhibitors (TKI). Nilotinib, a potent 2nd generation TKI, showed higher rates of major molecular response than imatinib, however was associated with higher rates of cardiovascular (CV) toxicity. Objectives To describe the CV events associated with nilotinib in a real-world CML population and assess the predictive value of the HFA-ICOS baseline risk score in clinical practice. Methods The HFA-ICOS baseline risk was calculated (low, medium, high /very high) for patients with CML treated with nilotinib between 2006 and 2021. The incidence of all CV events, ischaemic events and Major CV Adverse Events (MACE) were reviewed and compared among the different risk groups. Results A total of two hundred and twenty-nine eligible patients were included in the analysis. The incidence of CV events, ischaemic events, and MACE, while on nilotinib, were 20.9% (95% CI: 15.7% to 26.2%), 12.7% (95% CI: 8.4% to 16.9%), and 12.2% (95% CI: 7.9% to 16.5%) respectively, following a median duration of treatment with nilotinib of 34.4 months for the entire cohort. Patients with a higher HFA-ICOS baseline risk score had higher rates of all CV events (low: 11.2%, medium: 28.2% [HR: 2.8, 95% CI: 1.2 to 6.2], high/very high: 32.4% [HR: 3.5, 95% CI: 1.8 to 6.8]), ischaemic events (low: 5.2%, medium: 17.9% [HR: 3.7, 95% CI: 1.2 to 10.9] , high/very high: 21.6% [HR: 3.7, 95% CI: 1.4 to 9.7]) and MACE (low: 7.8% , medium: 10.3% [HR:1.2, 95% CI: 0.38 to 4.1], high/very high: 20.2% [HR: 2.2, 95% CI: 0.9 to 5.3]). The predictive tool presented an 89% NPV, and an area under the ROC curve: 0.65 for all CV events, an NPV of 95% and AUC 0.68 for ischaemic events and NPV 92% and AUC 0.62 for MACE. Conclusions The HFA-ICOS risk stratification tool has been shown to be an efficient discriminator at low, medium and high/very high risk of developing cardiovascular events, with an overall positive trend towards increasing cardiotoxicity rates with rising risk categories. This study provides evidence to support the use of this predictive tool in nilotinib treated patients, as it also underscores the potential for further improvement in the overall discriminatory ability of the model.

Tyrosine kinase inhibitors in the treatment of leptomeningeal carcinomatosis.

Leptomeningeal carcinomatosis (LMC) is a devastating complication of advanced cancers, such as lung cancer and breast cancer, which is usually indicative of a poor prognosis. The current treatments for LMC include palliative care, with others aiming to prolong survival and relieve neurological symptoms. Traditional treatments for LMC include radiotherapy, systemic chemotherapy, and intrathecal injection. Furthermore, the application of molecularly targeted agents, such as antiepidermal growth factor receptor (anti-EGFR), antihuman epidermal growth factor receptor 2 (anti-HER2), and anti-PD-1 monoclonal antibody, have prolonged the survival of LMC patients. Targeted therapy with tyrosine kinase inhibitors has also been proven to be an effective treatment. Tyrosine kinases can be overactive or expressed at high levels in some cancer cells; therefore, the use of tyrosine kinase inhibitors may prevent the activation of tumor-related pathways, preventing cancer cell growth. The EGFR family are cell surface receptors directly related to tumor occurrence with tyrosine kinase activity; it is the most widely used target for tyrosine kinase inhibitors in the treatment of LMC. In this review, we introduced the clinical manifestation and diagnostic criteria of LMC, clarified the treatment mechanism of tyrosine kinase inhibitors for LMC with mutations in EGFR, HER2, or anaplastic lymphoma kinase, reviewed the current application of various generation tyrosine kinase inhibitors in patients with LMC, and discussed new clinical trials and the future directions of tyrosine kinase inhibitor therapy.

Structure optimization, synthesis and bioactivity evaluation of novel BCR-ABL tyrosine kinase inhibitor targeting T315I mutation

Chronic Myeloid Leukemia (CML) is a malignant hematologic tumor caused by BCR-ABL fusion protein that binds with ATP to exert tyrosinase activity and persistently activates downstream phosphorylation pathways. The tyrosine kinase inhibitors (TKIs) represented by Imatinib are the key clinical therapy to the CML. While the mutations on the target lead to the serious drug resistance problems, especially the T315I mutation remains an unresolved challenge, and the cardiotoxicity has limited the clinical application of the third generation TKI Ponatinib despite its favorable efficacy against the T315I mutation. Even though, structural optimization of Ponatinib remains a potential strategy to overcome the resistance imposed by the mutation. Herein, we present a series of novel BCR-ABL/T315I tyrosine kinase inhibitors obtained by virtual screening using ZINC21710815, a BCR-ABL/T315I inhibitor reported earlier by our team, as a lead compound, and structural optimization of lead compounds against the T315I mutation, as well as screening of two novel compounds by activity evaluation and mechanistic studies, W4 and W8. W4 and W8 have better cell death-inducing effects and special selectivity against BaF3/T315I, which are worthy of further in-depth study to obtain more desirable anti-CML drugs as lead compounds.

Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Cancer: Current Use and Future Prospects.

Tyrosine kinase inhibitors (TKIs) have emerged as a leading targeted cancer therapy, reducing the side effects often seen with non-targeted treatments, especially the damage to healthy cells. To tackle resistance, typically caused by epidermal growth factor receptor (EGFR) mutations, four generations of TKIs have been developed. Each generation has shown improved effectiveness and fewer side effects, resulting in better patient outcomes. For example, patients on gefitinib, a first-generation TKI, experienced a progression-free survival (PFS) of 10 months compared to 5 months with conventional chemotherapy. Second-generation TKI afatinib outperformed erlotinib and extended PFS to 11.1 months compared to 6.9 months with cisplatin. Third-generation TKIs further increased survival to 38.6 months, compared to 31.8 months with first-generation TKIs. This progress demonstrates the ability of newer TKIs to overcome resistance, particularly the T790M mutation, while reducing adverse effects. Ongoing research focuses on overcoming resistance from newer mutations like C797S to further improve patient survival. These developments highlight the significant progress in TKI therapy and the continued effort to refine cancer treatment. Recent research in South Korea shows that third-generation TKIs are ineffective against non-small cell lung cancer (NSCLC) with the C797S mutation. Several trials have started showing promising in vitro and in vivo results, but more trials are needed before clinical approval. This review underscores notable advancements in the field of EGFR TKIs, offering a comprehensive analysis of their mechanisms of action and the progression of various TKI generations in response to resistance.

NVL-655 Is a Selective and Brain-Penetrant Inhibitor of Diverse ALK-Mutant Oncoproteins, Including Lorlatinib-Resistant Compound Mutations.

Three generations of tyrosine kinase inhibitors (TKI) have been approved for anaplastic lymphoma kinase (ALK) fusion-positive non-small cell lung cancer. However, none address the combined need for broad resistance coverage, brain activity, and avoidance of clinically dose-limiting TRK inhibition. NVL-655 is a rationally designed TKI with >50-fold selectivity for ALK over 96% of the kinome tested. In vitro, NVL-655 inhibits diverse ALK fusions, activating alterations, and resistance mutations, showing ≥100-fold improved potency against ALKG1202R single and compound mutations over approved ALK TKIs. In vivo, it induces regression across 12 tumor models, including intracranial and patient-derived xenografts. NVL-655 inhibits ALK over TRK with 22-fold to >874-fold selectivity. These preclinical findings are supported by three case studies from an ongoing first-in-human phase I/II trial of NVL-655 which demonstrate preliminary proof-of-concept clinical activity in heavily pretreated patients with ALK fusion-positive non-small cell lung cancer, including in patients with brain metastases and single or compound ALK resistance mutations. Significance: By combining broad activity against single and compound ALK resistance mutations, brain penetrance, and selectivity, NVL-655 addresses key limitations of currently approved ALK inhibitors and has the potential to represent a distinct advancement as a fourth-generation inhibitor for patients with ALK-driven cancers.

1274P Osimertinib versus first/second generation tyrosine kinase inhibitors as first-line therapy for metastatic EGFR-mutated non-small cell lung carcinoma: Overall survival using real-world data from TriNetX platform

1274P Osimertinib versus first/second generation tyrosine kinase inhibitors as first-line therapy for metastatic EGFR-mutated non-small cell lung carcinoma: Overall survival using real-world data from TriNetX platform

PrPC controls epithelial-to-mesenchymal transition in EGFR-mutated NSCLC: implications for TKI resistance and patient follow-up

Patients with EGFR-mutated non-small cell lung cancer (NSCLC) benefit from treatment with tyrosine kinase inhibitors (TKI) targeting EGFR. Despite improvements in patient care, especially with the 3rd generation TKI osimertinib, disease relapse is observed in all patients. Among the various processes involved in TKI resistance, epithelial-to-mesenchymal transition (EMT) is far from being fully characterized. We hypothesized that the cellular prion protein PrPC could be involved in EMT and EGFR-TKI resistance in NSCLC. Using 5 independent lung adenocarcinoma datasets, including our own cohort, we document that the expression of the PRNP gene encoding PrPC is associated with EMT. By manipulating the levels of PrPC in different EGFR-mutated NSCLC cell lines, we firmly establish that the expression of PrPC is mandatory for cells to maintain or acquire a mesenchymal phenotype. Mechanistically, we show that PrPC operates through an ILK-RBPJ cascade, which also controls the expression of EGFR. Our data further demonstrate that PrPC levels are elevated in EGFR-mutated versus wild-type tumours or upon EGFR activation in vitro. In addition, we provide evidence that PRNP levels increase with TKI resistance and that reducing PRNP expression sensitizes cells to osimertinib. Finally, we found that plasma PrPC levels are increased in EGFR-mutated NSCLC patients from 2 independent cohorts and that their longitudinal evolution mirrors that of disease. Altogether, these findings define PrPC as a candidate driver of EMT-dependent resistance to EGFR-TKI in NSCLC. They further suggest that monitoring plasma PrPC levels may represent a valuable non-invasive strategy for patient follow-up and warrant considering PrPC-targeted therapies for EGFR-mutated NSCLC patients with TKI failure.

Development and validation of a nomogram to predict poor efficacy of imatinib in the treatment of newly diagnosed chronic phase chronic myeloid leukemia patients.

Imatinib is the most widely used tyrosine kinase inhibitor (TKI) in patients with newly diagnosed chronic-phase chronic myeloid leukemia(CML-CP). However, failure to achieve optimal response after imatinib administration, and subsequent switch to second-generation TKI therapy results in poor efficacy and induces drug resistance. In the present study, we developed and validated a nomogram to predict the efficacy of imatinib in the treatment of patients newly diagnosed with CML-CP in order to help clinicians truly select patients who need 2nd generation TKI during initial therapy and to supplement the risk score system. We retrospectively analyzed 156 patients newly diagnosed with CML-CP who met the inclusion criteria and were treated with imatinib at the Second Affiliated Hospital of Xi'an Jiao Tong University from January 2012 to June 2022. The patients were divided into a poor-response cohort (N = 60)and an optimal-response cohort (N = 43) based on whether they achieved major molecular remission (MMR) after 12 months of imatinib treatment. Using univariate and multivariate logistic regression analyses, we developed a chronic myeloid leukemia imatinib-poor treatment (CML-IMP) prognostic model using a nomogram considering characteristics like age, sex, HBG, splenic size, and ALP. The CML-IMP model was internally validated and compared with Sokal, Euro, EUTOS, and ELTS scores. The area under the curve of the receiver operator characteristic curve (AUC)of 0.851 (95% CI 0.778-0.925) indicated satisfactory discriminatory ability of the nomogram. The calibration plot shows good consistency between the predicted and actual observations. The net reclassification index (NRI), continuous NRI value, and the integrated discrimination improvement (IDI) showed that the nomogram exhibited superior predictive performance compared to the Sokal, EUTOS, Euro, and ELTS scores (P < 0.05). In addition, the clinical decision curve analysis (DCA) showed that the nomogram was useful for clinical decision-making. In predicting treatment response, only Sokal and CML-IMP risk stratification can effectively predict the cumulative acquisition rates of CCyR, MMR, and DMR (P<0.05). We constructed a nomogram that can be effectively used to predict the efficacy of imatinib in patients with newly diagnosed CML-CP based on a single center, 10-year retrospective cohort study.

A Higher Neutrophil Count Is Associated with Favorable Achievement of Treatment-Free Remission in Patients with Chronic Myeloid Leukemia Who Received Second Generation Tyrosine Kinase Inhibitor as Frontline Treatment.

ABL1 tyrosine kinase inhibitor discontinuation securely became among the therapeutic goal for chronic myeloid leukemia chronic phase patients (CML-CP). To establish successful prognostic factors for treatment-free remission (TFR), it is necessary to diagnose the patients with high-risk molecular relapse, however, a biomarker for the achievement of TFR has not been completely elucidated. Recent investigations have determined that neutrophils function crucially in cancer immunology. The research was a multicenter retrospective observational study to examine the correlation between TFR and neutrophil counts before TKI discontinuation. The investigation included patients having Philadelphia chromosome-positive CML-CP who attempted the discontinuation of TKIs after a durable deep molecular response between January 2012 and July 2021 at four institutions in Japan. 118 CML-CP patients in total discontinued TKIs and an estimated 36-month TFR rate was 65.1%. 52 patients received second-generation TKIs as frontline. Higher neutrophil count (>3210/μL) at TKIs discontinuation was determined as an independent prognostic variable for TFR in patients who received second-generation TKIs as frontline [(HR, 0.235 (95%, confidence interval (CI) 0.078-0.711); p = 0.010]. The neutrophil-mediated immunomodulation can be a significant component for the effective achievement of TFR in CML supported by our clinical observation.

Titania-Graphene Oxide Nanocomposite-Based Philadelphia-Positive Leukemia Therapy.

Philadelphia-positive (Ph+) leukemia is a type of blood cancer also known as acute lymphoblastic leukemia (ALL), affecting 20-30% of adults diagnosed worldwide and having an engraved prognosis as compared to other types of leukemia. The current treatment regimens mainly rely on tyrosine kinase inhibitors (TKIs) and bone marrow transplants. To date, several generations of TKIs have been developed due to associated resistance and frequent relapse, with cardiovascular system anomalies being the most devastating complication. Nanotechnology has the potential to address these limitations by the targeted drug delivery and controlled release of TKIs. This study focused on the titanium dioxide (TiO2) and graphene oxide (GO) nanocomposite employment to load nilotinib and ponatinib TKIs for therapy of Ph+ leukemia cell line (K562) and Ba/F3 cells engineered to express BCR-ABL oncogene. Meanwhile, after treatment, the oncogene expressing fibroblast cells (Rat-1 P185) were evaluated for their colony formation ability under 3D conditions. To validate the nanocomposite formation, the TiO2-GO nanocomposites were characterized by scanning electron microscope, DLS, XRD, FTIR, zeta potential, EDX, and element mapping. The TKI-loaded TiO2-GO was not inferior to the free drugs after evaluating their effects by a cell viability assay (XTT), apoptosis induction, and colony formation inhibition. The cell signaling pathways of the mammalian target of rapamycin (mTOR), signal transducers and activators of transcription 5 (STAT5), and extracellular signal-regulated kinase (Erk1/2) were also investigated by Western blot. These signaling pathways were significantly downregulated in the TKI-loaded TiO2-GO-treated groups. Based on the findings above, we can conclude that TiO2-GO exhibited excellent drug delivery potential that can be used for Ph+ leukemia therapy in the future, subject to further investigations.

Mutation and cell state compatibility is required and targetable in Ph+ acute lymphoblastic leukemia minimal residual disease.

Efforts to cure BCR::ABL1 B cell acute lymphoblastic leukemia (Ph+ ALL) solely through inhibition of ABL1 kinase activity have thus far been insufficient despite the availability of tyrosine kinase inhibitors (TKIs) with broad activity against resistance mutants. The mechanisms that drive persistence within minimal residual disease (MRD) remain poorly understood and therefore untargeted. Utilizing 13 patient-derived xenograft (PDX) models and clinical trial specimens of Ph+ ALL, we examined how genetic and transcriptional features co-evolve to drive progression during prolonged TKI response. Our work reveals a landscape of cooperative mutational and transcriptional escape mechanisms that differ from those causing resistance to first generation TKIs. By analyzing MRD during remission, we show that the same resistance mutation can either increase or decrease cellular fitness depending on transcriptional state. We further demonstrate that directly targeting transcriptional state-associated vulnerabilities at MRD can overcome BCR::ABL1 independence, suggesting a new paradigm for rationally eradicating MRD prior to relapse. Finally, we illustrate how cell mass measurements of leukemia cells can be used to rapidly monitor dominant transcriptional features of Ph+ ALL to help rationally guide therapeutic selection from low-input samples.

What is a bad ALK? A scoping review of molecular markers of poor prognosis.

e20530 Background: Patients with non-small cell lung cancer (NSCLC) with anaplastic lymphoma kinase ( ALK) rearrangements derive a significant and durable clinical benefit from tyrosine kinase inhibitors (TKI). However, a portion of patients have progressive disease as their best response and progress to death much earlier than expected which is termed primary resistance. This scoping review aims to summarize the known molecular mechanisms that underlie this lethal ALK phenotype. Methods: We performed a systematic scoping review from scientific databases such as Ovid Medline, Ovid Embase, and Cochrane Central Register of Controlled Trials. Data was extracted from the database inception to March 13, 2023. Studies included molecular markers of poor prognosis, with a focus on TP53, variant 3 re-arrangements, and reports of poor clinical response to TKIs (defined as progression-free survival less than 3 months on 1st line TKI or overall survival less than 2 years from exposure to 1st line TKI). 2nd generation and 3rd generation ALK TKI clinical trial data were also included. Results: A total of 4360 studies were screened and 136 studies were included. Numerous studies implicated the negative prognostic role of variant 3 likely mediated through the acquisition of on-target resistance mutations compared to other variants. TP53 mutations were also associated with a worse prognosis and implicated with greater chromosomal instability and mutational burden. Furthermore, reports of both variant 3 and TP53 mutations together were associated with even worse survival suggesting both molecular mechanisms combined can confer primary resistance phenotype. Other mediators of primary resistance included aberrations in cell cycle regulators such as CDKN2A/B loss, mutations in cell signalling pathways such as the PI3K/ AKT/mTOR pathway, deficiencies in DNA repair mechanisms, and uncommon fusion partners. Consistent with these prior studies, comprehensive genomic analysis from clinical trial data of 2nd generation and 3rd generation TKIs was unable to identify a singular genomic signature that underlies this lethal phenotype. However, a general trend from the literature suggested that the combination of multiple aberrations is likely necessary to confer a primary resistance phenotype, though the relative contribution of each somatic mutation likely will vary. Conclusions: This scoping review highlights that in NSCLC, the lethal ALK phenotype is likely composed of a heterogeneous population of various combinations of poor prognostic factors including variant 3, mutations in cell cycle regulators and other aberrations in cell signalling pathways. There remains an unmet need for a genomic assay to integrate all these various molecular markers to predict the lethal ALK phenotype.

Tyrosine kinase inhibitors with and without upfront CNS radiation for brain metastases in oncogene-driven non-small cell lung cancer (TURBO-NSCLC).

2019 Background: Newer generation tyrosine kinase inhibitors (TKI) for NSCLC with EGFR mutations and ALK rearrangements have demonstrated encouraging central nervous system (CNS) activity with CNS objective response rates, greatly improved from 1st generation TKIs. In response to these data, guideline statements have acknowledged a strategy of CNS-penetrant TKI +/- upfront stereotactic radiosurgery (SRS) for the treatment of select patients with BM. However, optimal use of upfront SRS for BM in these patients is controversial since upfront CNS radiation has been the historical standard of care, and there are limited data guiding patient management with upfront TKI alone. Additionally, results from a large multi-institutional series reported inferior overall survival (OS) with the omission of SRS in patients with EGFR-mutated NSCLC treated with first-generation TKI. Methods: Data on TKI-naïve patients with EGFR- and ALK-driven NSCLC with BM treated with CNS-penetrant TKIs +/- upfront SRS were retrospectively collected from 7 centers in the United States. Time to CNS progression (PD), local CNS PD, and OS were analyzed, with multivariable adjustment (MVA) in Fine and Gray and Cox proportional hazards models for baseline factors including age, sex, performance status, mutation, extracranial metastases, prior therapy, neurologic symptoms, and number and size of BM. Results: We identified 317 patients (200 TKI only and 117 TKI+SRS). 250 (79%) and 61 (19%) patients received osimertinib and alectinib, respectively. Patients who received TKI+SRS were more likely to have BM ≥1 cm (p&lt;0.001) and neurologic symptoms (p&lt;0.001) at baseline. The median follow-up from treatment of BM was 23 months and 26 months in the TKI and TKI+SRS groups, respectively. Median OS was similar between the TKI and TKI+SRS groups (median 41 months [95% CI: 35-NR] vs 40 months [95% CI: 40-NR], respectively; p=0.5). On MVA, TKI+SRS was associated with a significant improvement in time to CNS PD (HR 0.63; 95% CI: 0.42-0.96; p=0.033). Local CNS control was significantly improved with TKI+SRS (HR 0.30, 95% CI: 0.16-0.55; p&lt;0.001), whereas no significant differences were observed in distant CNS control. Subgroup analyses demonstrated greater CNS control benefits with TKI+SRS in patients with BM ≥1 cm. Conclusions: This is the largest multi-institutional study comparing strategies of CNS-penetrant TKIs +/- upfront SRS in TKI-naïve patients with oncogene-driven NSCLC. The addition of SRS improved time to CNS PD and local CNS control but not OS. Patients with BM ≥1 cm may benefit the most from upfront integration of SRS. [Table: see text]

OSIRAM-1/TORG1833: Overall survival results of a randomized phase II study of osimertinib plus ramucirumab versus osimertinib alone as initial chemotherapy for EGFR mutation-positive non-squamous non-small cell lung cancer.

8613 Background: Dual inhibition of the EGFR/VEGF pathways has demonstrated superior efficacy with 1st generation EGFR tyrosine kinase inhibitor (TKI) in patients with non-small cell lung cancer (NSCLC) harboring EGFR mutations. This study aims to evaluate the efficacy and safety of combining osimertinib (Osi), a 3rd generation TKI considered the standard of care, with ramucirumab (Ram). We have previously shown the result of progression free survival (PFS) as a primary endpoint, the median PFS was 20.0 months for Osi+Ram and 24.0 months for Osi, hazard ratio of 1.054 (95% CI 0.674-1.648). In further analyses, we aimed to examine the effects of this combination therapy on overall survival (OS). Methods: Previously untreated EGFR mutation-positive advanced non-squamous NSCLC patients with a performance status of 0 or 1 were eligible. Asymptomatic and/or treated brain metastases were included. Eligible patients were randomized at a 1:1 ratio to receive Osi (80mg) every day either without or with Ram (10mg/kg) every 2 weeks until disease progression or unacceptable toxicity, stratified according to gender and the type of EGFR mutation (exon 19 deletion, L858R). The primary endpoint was PFS assessed by the independent blinded radiologic reviewer. Secondary endpoints included PFS assessed locally, objective response rate (ORR), disease control rate (DCR), duration of response (DOR), OS and safety. Results: Between November 2018 and April 2020, 122 patients (Osi+Ram: 59, Osi: 63) were enrolled. The patients' characteristics were well balanced. 59% were females, and 61% had an exon 19 deletion. Median age was 70 years old (range, 29-86). With a median follow up of 36.0 months, the median OS was 43.4 months (95% CI 36.5-N.R.) for Osi+Ram and N.R. (95% CI 41.3-N.R.) for Osi, resulting in a hazard ratio of 1.159 (95% CI 0.645-2.083, p = 0.62). Median treatment duration for Ram was 140 (14-1239) days. Ram was discontinued in 45 patients (76%) by the treatment related adverse effects. Common reasons for Ram discontinuation were platelet count decreased (n=14), proteinuria (n=12), neutrophil count decreased (n=11), pneumonitis (n=3), bleeding (n=3) and infection (n=3). Pneumonitis was observed in 16% in Osi, 9% in Osi+Ram, with grade 3 observed in 2% of both arms. Conclusions: Both treatment arms demonstrated sustained OS over 43 months. However, this study did not show an advantage of biweekly Ram administration with Osi in terms of PFS and OS. Notably, there was surpassed increase of early discontinuation of Ram due to higher adverse events. Clinical trial information: 2080224085 .

Revealing and targeting metabolic drivers contributing to treatment escape in diffuse midline glioma.

10038 Background: Diffuse midline glioma (DMG) is an aggressive pediatric brain tumor that predominately affects children, with a median survival of 9-11 months. DMGs are driven by self-renewing, stem-like glioma cells that have been stalled in an oligodendrocyte precursor cell (OPC)-like state and that highly express PDGFRA. This overexpression of PDGFRA has been shown to be pivotal in DMG development. Thus, targeting PDGFRA may serve as a viable treatment approach for DMG. In our previous studies, we revealed that avapritinib, a next generation tyrosine kinase inhibitor of PDGFRA, is highly effective in DMG cells. While a subset of patients receiving treatment with avapritinib experienced a promising clinical response, all patients eventually experienced tumor progression due to treatment escape. In this study, we investigated which mechanisms DMG cells use to escape avapritinib treatment, and how we can therapeutically exploit these resistance mechanisms. Methods: Transcriptomic profiling and functional assays were performed on patient-derived DMG cell lines. A combinatorial drug screening identified drug candidates evaluated in this study. Results: Bulk RNA sequencing analysis of two patient derived DMG cell lines revealed an upregulation of genes associated with both fatty acid metabolism and oxidative phosphorylation (OXPHOS) following avapritinib treatment. Functional assays confirmed elevated OXPHOS in avapritinib-treated cells with significant increases in mitochondrial energy transduction, palmitate- (a product of fatty acid metabolism) driven oxygen consumption rates, and incorporation of palmitate-derived carbons into the tricarboxylic acid (TCA) cycle. CRISPR-Cas9-mediated knockout of PDGFRAin one DMG cell line confirmed the metabolic changes observed following avapritinib treatment. Analysis of bulk RNA sequencing data revealed an upregulation of key fatty acid- related transcription factors in avapritinib-treated DMG cells. Specifically, Peroxisome Proliferator-Activated Receptor alpha (PPAR-alpha), Sterol Regulatory Binding Element Binding Transcription Factors 1 and 2, and Fatty Acid Synthase (FASN) were most prominently upregulated. To determine which therapies could target the dependency of avapritinib-treated cells on fatty acid metabolism, we performed a combinatorial drug screening and found three lipid pathway inhibitors that have synergistic cytotoxic effects with avapritinib. Specifically, a FASN inhibitor, cholesterol pathway inhibitor, and PPAR-alpha inhibitor. Conclusions: In this study, we revealed metabolic drivers that may contribute to avapritinib resistance in DMG cells, and identified compounds capable of inhibiting these drivers that demonstrate synergy with avapritinib. We now intend on testing these combination therapies in vivo as we aim to provide a long-term clinical benefit to DMG patients receiving avapritinib.

Phase 1 study of BDTX-1535, an oral 4th generation covalent EGFR inhibitor, in patients with recurrent glioblastoma: Preliminary dose escalation results.

2068 Background: Epidermal growth factor receptor ( EGFR) gene is the most frequently altered oncogenic driver in glioblastoma (GBM). In-frame deletion alterations (e.g., EGFRvIII) and missense mutations co-occur in the setting of EGFR gene amplification and are characterized as a hallmark of disease pathogenesis in GBM. BDTX-1535 is an oral, highly potent, brain penetrant, selective, irreversible 4th generation tyrosine kinase inhibitor that targets EGFR alterations in GBM and NSCLC. Preliminary results of the Phase 1 dose escalation study (NCT05256290) of patients with recurrent GBM (rGBM) are presented here. Methods: BDTX-1535-101 is a first-in-human study that enrolled patients with either rGBM harboring EGFR alterations following standard of care or patients with locally advanced or metastatic EGFR mutated NSCLC that progressed on prior EGFR TKIs. Using an adaptive Bayesian optimal interval design in the Phase 1 part, patients were enrolled at increasing dose cohorts and were treated daily for 21-day cycles until treatment discontinuation. The primary objective was to determine the BDTX-1535 recommended Phase 2 dose based on the overall safety, PK, pharmacodynamics, and preliminary antitumor activity. Results: Twenty-seven patients with rGBM were enrolled in the Phase 1 cohort that consisted of 54 patients in total including 27 patients with NSCLC. Patients were treated across seven dose levels (15mg – 400mg QD). The mean age of patients with rGBM was 58.7 years (range 41-85) with 96% of patients with previous temozolomide (TMZ) treatment and a median of 2 lines of prior therapy (range 1-4). The most common all-grade treatment-related AEs across all cohorts were rash (78%), diarrhea (41%), fatigue (15%), stomatitis (11%), decreased appetite (11%), nausea (11%) and paronychia (11%). Gr 3 TRAEs ≥ 10% included rash (19%) reported at 300 or 400 mg QD doses. Plasma exposure of BDTX-1535 increased dose proportionally and had a half-life of ~15h, supporting once daily dosing. The maximum tolerated dose (MTD) is 300 mg QD. Among 19 evaluable patients for response based on RANO criteria, 1 confirmed partial response was observed and 8 patients achieved stable disease. Five patients remained on BDTX-1535 with stable disease for an extended period (&gt;5 months) who previously performed poorly on TMZ with short treatment duration, and 1 patient continues on BDTX-1535 after 16 months of treatment. Conclusions: BDTX-1535 was well-tolerated up to 300mg daily, which is the MTD, and promising preliminary clinical activity was observed in patients with rGBM after relapse on standard of care treatment. Given the inability to reconfirm EGFR status at the time of treatment with BDTX-1535 in this Phase 1 trial, further exploration of BDTX-1535 in a “window of opportunity” study is ongoing (NCT06072586). Clinical trial information: NCT05256290 .

Toxicities associated with tyrosine kinase inhibitor maintenance following allogeneic hematopoietic cell transplantation in Philadelphia chromosome-positive acute lymphoblastic leukemia.

Allogeneic hematopoietic cell transplantation (HCT) offers a potential cure in Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL); nonetheless, relapses are common and the major cause of mortality. One strategy to prevent relapse is tyrosine kinase inhibitor (TKI) maintenance post-HCT, but published clinical experience is primarily with the first-generation TKI imatinib while data with newer generation TKIs are limited. We conducted a retrospective analysis of 185 Ph+ ALL patients who underwent HCT followed by TKI maintenance from 2003 to 2021 at City of Hope. Initially, 50 (27.0%) received imatinib, 118 (63.8%) received a second-generation TKI (2G-TKI), and 17 (9.2%) received ponatinib. A total of 77 patients (41.6%) required a dose reduction of their initial TKI due to toxicity. Sixty-six patients (35.7%) did not complete maintenance due to toxicity; 69 patients (37.3%) discontinued 1 TKI, and 11 (5.9%) discontinued 2 TKIs due to toxicity. Initial imatinib versus 2G-TKI versus ponatinib maintenance was discontinued in 19 (38.0%) versus 68 (57.6%) versus 3 (17.6%) patients due to toxicity (p = .003), respectively. Patients on ponatinib as their initial TKI had a longer duration of TKI maintenance versus 2G-TKI: 576.0 days (range, 72-921) versus 254.5 days (range, 3-2740; p = .02). The most common reasons for initial TKI discontinuation include gastrointestinal (GI) intolerance (15.1%), cytopenia (8.6%), and fluid retention (3.8%). The 5-year overall survival and progression-free survival for the total population were 78% and 71%, respectively. Our findings demonstrate the challenges of delivering post-HCT TKI maintenance in a large real-world cohort as toxicities leading to TKI interruptions, discontinuation, and dose reduction were common.

Weekly Afatinib in the Treatment of Advanced Non-small Cell Lung Cancer with EGFR-G719C Mutation Followed by Lobectomy: A Case Report

Introduction: Lung cancer stands as the leading cause of cancer-related deaths worldwide. Over the past three decades, the advent of tyrosine kinase inhibitors (TKIs) has marked a significant turning point in the treatment of non-small cell lung cancer (NSCLC) harboring EGFR mutations. Notably, high response rates have been observed in cases with exon 19 deletions (Del19) and Exon 21 substitution L858R mutations. Conversely, the G719X mutation on exon 18 is less prevalent, with variable sensitivity across different generations of TKIs. Afatinib, a second-generation inhibitor, gained FDA approval for the initial treatment of EGFR-mutant metastatic NSCLC in 2013, though its role remains incompletely understood within a multidisciplinary treatment framework, particularly in combination with surgery. However, the standard daily dose of 40mg Afatinib has demonstrated poor tolerability, often resulting in adverse events such as diarrhea and skin toxicity, leading to treatment discontinuation. A recent strategy involving a weekly dose of 280mg Afatinib has shown promising outcomes and a reduced risk of adverse events. Case Presentation: This case report highlights a 50 - year-old female diagnosed with stage IVa right lung adenocarcinoma metastasizing to the left lung (cT3N0M1a), revealing the rare EGFR-G719C (exon18) mutation. Following this diagnosis, the patient underwent open lobectomy. Nine months post-surgery, a treatment approach involving 280mg weekly Afatinib was initiated. Subsequently, the patient was closely monitored for 16 months with no signs of recurrence. Conclusions: EGFR G719C exhibits sensitivity to Afatinib, endorsing the use of Afatinib with fewer adverse events compared to the traditional daily dosage. Our case further advocates for collaborative strategies between medical oncologists and surgeons in the management of advanced-stage NSCLC.

The initial molecular response predicts the deep molecular response but not treatment-free remission maintenance in a real-world chronic myeloid leukemia cohort.

In chronic myeloid leukemia, the identification of early molecular predictors of stable treatment-free remission (TFR) after tyrosine kinase inhibitor (TKI) discontinuation is challenging. The predictive values of residual disease (BCR::ABL1 quantification) at month 3 and 6 and more recently, BCR::ABL1 transcript halving time (HT) have been described, but no study compared the predictive value of different early parameters. Using a real-world cohort of 408 patients, we compared the performance of the EUTOS long-term survival (ELTS) score, BCR::ABL1 HT, and residual disease at month 3 and 6 to predict the molecular response, achievement of the TKI discontinuation criteria, and TFR maintenance. The performances of BCR::ABL1 HT and residual disease at month 3 were similar. Residual disease at month 6 displayed the best performance for predicting the optimal response (area under the ROC curve between 0.81 and 0.92; cut-off values: 0.11% for MR4 at month 24 and 0.12% for MR4.5 at month 48). Conversely, no early parameter predicted reaching the TKI discontinuation criteria and TFR maintenance. We obtained similar results when patients were divided in subgroups by first-line treatment (imatinib vs. second-generation TKI [2G-TKI]). We identified a relationship between ELTS score, earlier milestones and TFR maintenance only in the 2G-TKI group. In conclusion, this first comparative study of early therapeutic response parameters showed that they are excellent indicators of TKI efficacy (BCR::ABL1 transcript reduction) and best responders. Conversely, they did not predict the achievement of the TKI discontinuation criteria and TFR maintenance, suggesting that other parameters are involved in TFR maintenance.

Incidence of pleural effusion with dasatinib and the effect of switching therapy to a different TKI in patients with chronic phase CML

Dasatinib is one of the second generation tyrosine kinase inhibitors (TKI) which is approved for the treatment of patients with chronic phase CML (CP-CML) both in the front line and in the second line setting. Pleural effusion (PE) is a unique toxicity associated with dasatinib use. Our aim was to study the incidence of pleural effusion in our cohort of patients who were treated with dasatinib for CP-CML and the safety upon TKI switch. A total of 390 patients were treated with dasatinib during their course of treatment for CP-CML. A total of 69 patients (17.6%) developed any grade of PE. About 33 (48%) patients developed CTCAE grade 2 PE, 34 (49%) grade 3 and only 1 patient developed grade 4 PE. Recurrence of PE was observed in 34 (49%) patients. While only 12 patients (17.3%) continued using dasatinib after development of PE, dasatinib was discontinued in the other 57 patients. Therapy was switched to bosutinib in 13 patients out of which 6 (46%) patients re-developed PE. While only 12.5% patients developed re-accumulation of pleural fluid in patients switched to imatinib, none of the patients switched to nilotinib re-developed PE. A change in TKI to bosutinib was associated with a 46% risk of recurrence of PE in patients who develop PE on dasatinib for the treatment of CP-CML. The incidence of recurrent PE was markedly lower in patient switched to imatinib or nilotinib.