Potent Tyrosine Kinase Inhibitor Research Articles

Synthesis, docking study, and antitumor evaluation of benzamides and oxadiazole derivatives of 3-phenoxybenzoic acid as VEGFR-2 inhibitors.

Current chemotherapeutic agents have several limitations, including lack of selectivity, the development of undesirable side effects, and chemoresistance. As a result, there is an unmet need for the development of novel small molecules with minimal side effects and the ability to specifically target tumor cells. A new series of 3-phenoxybenzoic acid derivatives, including 1,3,4-oxadiazole derivatives (4a-d) and benzamides derivatives (5a-e) were synthesized; their chemical structures were confirmed by Fourier-transform infrared spectroscopy, 1H nuclear magnetic resonance (NMR), 13C NMR, and mass spectra; and various physicochemical properties were determined. The antiproliferative activities of the new derivatives were evaluated by means of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Three compounds (4b, 4c, and 4d) exhibited cytotoxicity against two of the three cell lines tested, five compounds (3, 4a, 5a, 5b, and 5e) were toxic to one cell line, while two compounds (5c and 5d) were not cytotoxic to any of the three cell lines tested in the current study. Based on docking scores, MTT assay findings, and vascular endothelial growth factor receptor 2 (VEGFR-2) kinase activity data, Compound 4d was selected for further biological investigation. Flow cytometry was used to determine the mode of cell death (apoptosis vs. necrosis) and the effect on cell cycle progression. Compound 4d arrested HepG2 hepatocellular carcinoma cells in the G2/M phase and activated both the intrinsic and extrinsic apoptosis pathways. In conclusion, Compound 4d has shown promising results for future research as a potent VEGFR-2 tyrosine kinase inhibitor.

Abstract CT292: Phase II study of pembrolizumab in combination with lenvatinib in patients with triple negative breast cancer (TNBC), non-small cell lung cancer (NSCLC), and other tumor types and brain metastases

Abstract Background: Many patients develop brain metastasis during the course of their disease and it represents the cause of death in more than half of them. The prognosis and survival of patients with brain metastases remains poor with limited palliative treatment options. Thus, there is a need to develop new strategies for the therapeutic management of patients with brain metastases. Inflammatory stimuli originating from CNS tumors may increase the permeability of the blood-brain barrier and promote immune cell activation and infiltration into tumors. Several studies have demonstrated now the efficacy of immune checkpoint inhibitors in patients with melanoma with active brain metastases. The modulation of VEGF-mediated immune suppression via angiogenesis inhibition may augment the activity of immune checkpoint inhibitors. Lenvatinib is an oral, potent multiple receptor tyrosine kinase inhibitor that selectively inhibits VEGFRs, VEGFR1 (FLT1), VEGFR2 (KDR), and VEGFR3 (FLT4), in addition to other pro-angiogenic and oncogenic pathway-related receptor tyrosine kinases. The combination of lenvatinib and pembrolizumab is approved for patients with metastatic endometrial carcinoma and renal cancer, and it is investigated in other tumor types with promising preliminary results. We hypothesize that pembrolizumab and lenvatinib will be an effective treatment for TNBC, NSCLC, and other solid tumor types with brain metastases by decreasing angiogenic tumor activity and improving antitumor T-cell activity. Methods: This is a single-center, open-label, multi-cohort Phase II study evaluating the efficacy and safety of pembrolizumab in combination with lenvatinib in patients with solid tumors and brain metastases. The study has 3 cohorts: triple negative breast cancer (TNBC), non-small cell lung cancer (NSCLC), and other solid tumor types with established or preliminary clinical evidence of efficacy of programmed cell death-1 (PD-1) and angiogenesis inhibitors. Eligible patients will have at least 1 unirraditated or progressing brain metastasis of 0.5-2 cm on brain MRI. The study is conducted using a Simon’s optimal two-stage design, and approximately 87 patients will be enrolled concurrently (n=29 per cohort). Pembrolizumab (200 mg intravenously on Day 1 of each cycle) and lenvatinib (20 mg orally once daily) are administered in 21-day cycles for a maximum of 24 months. The primary endpoint is intracranial objective response rate at 4 months as assessed by the modified Response Evaluation Criteria in Solid Tumors (mRECIST). Exploratory analyses will include evaluation of tissue and blood-based immune-related correlates of response to the pembrolizumab and lenvatinib combination. The first patient was enrolled in January 2022 and accrual of patients is ongoing (NCT05064280). Citation Format: Ecaterina E. Dumbrava, Emma J. Montazari, Uyen M. Vu, Tiantian Cai, Mehmet Altan, Nuhad K. Ibrahim, Debra N. Yeboa, Jing Li, Frederick F. Lang, Gisela Sanchez, Isabella C. Glitza, Barbara J. O'Brien, Rashmi K. Murthy, Jianbo Wang, Tanisha T. Darko, Denisse Velazquez, Komal Shah, Funda Meric-Bernstam, Hussein Tawbi, Jordi Rodon. Phase II study of pembrolizumab in combination with lenvatinib in patients with triple negative breast cancer (TNBC), non-small cell lung cancer (NSCLC), and other tumor types and brain metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT292.

Abstract 1961: Discovery of a highly potent and brain penetrant fourth generation EGFR tyrosine kinase inhibitor

Abstract Third generation EGFR tyrosine kinase inhibitors (TKIs) such as Osimertinib have emerged as first-line standard of care therapy to treat non-small cell lung cancer (NSCLC) patients with activating EGFR mutations (del19, L858R or T790M). However, within 12 to 18 months following treatment, 15-20% of the patients develop C797S mutation, which drives resistance to these drugs; with the progression of disease brain metastasis is observed in 40-70% of the EGFRm+ NSCLC patients. Here, we report a highly potent and brain penetrant fourth generation EGFR-TKI ACE-34237307, designed to overcome C797S mutation (del19/C797S and L858R/C797S), and common single point mutations (del19 and L858R). ACE-34237307 is also designed to potently inhibit the more prevalent non-canonical EGFR mutations such as G719S and L861Q. ACE-34237307 showed robust anti-proliferative activity against EGFR double mutations in Ba/F3 (EGFR-del19/C797S and EGFR-L858R/C797S) cell lines with IC50 values of 0.1 and 0.23 nM, respectively. In phospho-EGFR assay, ACE-34237307 demonstrates over 79-fold selectivity against A431 (EGFR-WT) cell line when compared to PC-9 (EGFR-del 19) cell line. ACE-34237307 is highly brain penetrant with B/P ratio of 2.3 in rat and 1.2 in mouse. It has an excellent pharmacokinetic profile in rat, mouse and dog with good bioavailability, a flat PK curve and reduced Cmax, which will translate to a better safety profile. The in vivo anti-tumor efficacy was evaluated in Osimertinib resistant double mutant Ba/F3-EGFR-del19/C797S and L858R/C797S as well as del19 and L858R single mutant xenograft models. It has been shown that ACE-34237307 at doses of ≥ 0.6 mg/kg induces complete tumor regression or eradication in all tumor models tested. In brain tumor models with Ba/F3 (EGFR-del19/C797S) and PC-9 (EGFR-del19), ACE-34237307 showed complete inhibition or eradication of brain tumors and drastically extended animal survival at ≥ 0.6 mg/kg. In summary, ACE-34237307 is a potent fourth generation EGFR-TKI with high WT selectivity, excellent brain penetration, highly favorable DMPK profile, outstanding in vivo efficacy in subcutaneous and brain tumor models and low projected human dose amenable to QD dosing. Citation Format: sanjeev kumar, junmei wang, wenqian li, weitao pan, zhiming wen, Kuo-Long yu, Genshi Zhao, tinggui yin. Discovery of a highly potent and brain penetrant fourth generation EGFR tyrosine kinase inhibitor [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 1961.

Abstract 2114: Enhancing therapeutic strategies for osimertinib-resistant EGFR-mutant NSCLC: A HER3 dual-payload ADC (dpADC) with topoisomerase I and EGFR tyrosine kinase inhibitor

Abstract Background: EGFR tyrosine kinase inhibitors (TKIs) have significantly improved the survival rate and the quality of life of the NSCLC patients with EGFR mutation in the first line setting. For example, Osimertinib, a potent third-generation EGFR TKI, has demonstrated exceptional efficacy in metastatic NSCLC with specific EGFR mutations. Despite its success, the emergence of drug resistance, often linked to elevated HER3 protein expression, remains a significant challenge. U3-1402 (HER3-Dxd), an HER3 ADC, demonstrates a promising result in managing Osimertinib-resistant NSCLC. It has been reported that combining U3-1402 with Osimertinib has shown enhanced efficacy in resistant cell lines and mouse models. Here, we explore a novel HER3 dual-payload ADC (HER3 dpADC), uniquely combining a Topoisomerase I inhibitor and an EGFR TKI within a single antibody structure using the enzymatic site-specific conjugation platform developed by GeneQuantum (GQ). This innovative approach demonstrates potent and synergistic anti-tumor effects in vitro and in vivo, presenting an alternative therapeutic strategy for EGFR-mutant NSCLC patients. Results: GQ's dpADC platform technology employs two orthogonal enzymatic site-specific conjugations and stable linker technologies to efficiently generate the dual-payload ADC with high homogeneity and quality. For HER3 dpADC, HER3 Ab was conjugated with a novel Topoisomerase I inhibitor, TopoIx, and an EGFR tyrosine kinase inhibitor. In vitro DAR analysis revealed high linker stability, with minimal free payload release even after 96 hours of plasma incubation. Binding affinity assessments confirmed comparable affinity between HER3 dpADC and HER3 mAb in specific EGFR exon 19 deletion cell lines. Using various NSCLC cell lines in a 3D-spheroid culture system, HER3 dpADC demonstrated significant dose-dependent and synergistic anti-tumor activities. A robust bystander killing efficacy was observed in both HER3+/HER3- HEK293T cell coculture assays. Evaluation in CDX mouse models consistently demonstrated heightened in vivo efficacy by HER3 dpADC, aligning with the promising in vitro data. In NSCLC patient-derived xenograft (PDX) mouse models representing EGFR tyrosine kinase inhibitor-sensitive or resistant phenotypes, HER3 dpADC induced tumor regressions with no obvious toxicity, underscoring its potential as the next-generation HER3 targeting agent. Conclusion: The innovative HER3 dpADC, leveraging an efficient dual enzymatic site-specific conjugation, exhibited robust anti-tumor efficacy in both in vitro and in vivo settings, surpassing single-agent treatments. Its synergistic mechanism of action presents a promising possibility for developing a more potent and the front-line therapeutic solutions in NSCLC patients who have progressed on standard therapies. Citation Format: Lina Wang, Meijun Xiong, Xinju Gao, Chengang Zhou, Yu Han, Yanchun Li, Junhao Wang, Lili Shi, Gang Qin, Paul H. Song. Enhancing therapeutic strategies for osimertinib-resistant EGFR-mutant NSCLC: A HER3 dual-payload ADC (dpADC) with topoisomerase I and EGFR tyrosine kinase inhibitor [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 2114.

Iridium-Catalyzed Asymmetric Hydrogenation of Heteroaromatics with Multiple N Atoms via Substrate Activation: An Entry to 4,5,6,7-Tetrahydropyrazolo[1,5-a]pyrimidine-3-carbonitrile Core of a Potent BTK Inhibitor.

The chiral 4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine is the key core skeleton of potent Bruton's tyrosine kinase (BTK) inhibitor Zanubrutinib, and the catalyst-controlled asymmetric hydrogenation of planar multinuclear pyrimidine heteroarenes with multiple N atoms could provide an efficient route toward its synthesis. Owing to the strong aromaticity and poisoning effect toward chiral transition metal catalyst, asymmetric hydrogenation of pyrazolo[1,5-a]pyrimidines with multiple nitrogen atoms is still a challenge for synthesizing the chiral 4,5,6,7-tetrahydropyrazolo[1,5-a]-pyrimidine. Herein, an efficient iridium-catalyzed asymmetric hydrogenation of pyrazolo[1,5-a]pyrimidines has been developed using substrate activation strategy, with up to 99% ee. The decagram scale synthesis further demonstrated the potential and promise of this procedure in the synthesis of Zanubrutinib. In addition, a mechanistic study indicated that the hydrogenation starts with 1,2-hydrogenation.

Predictive performance of population pharmacokinetic models of imatinib in chronic myeloid leukemia patients.

Chronic myeloid leukemia is a myeloproliferative neoplasm associated with the specific chromosomal translocation known as the Philadelphia chromosome. Imatinib is a potent BCR-ABL tyrosine kinase inhibitor, which is approved as the first line therapy for CML patients. There are various population pharmacokinetic studies available in the literature for this population. However, their use in other populations outside of their cohort for the model development has not been evaluated. This study was aimed to perform the predictive performance of the published population pharmacokinetic models for imatinib in CML population and propose a dosing nomogram. A systematic review was conducted through PubMed, and WoS databases to identify PopPK models. Clinical data collected in adult CML patients treated with imatinib was used for evaluation of these models. Various prediction-based metrics were used for assessing the bias and precision of PopPK models using individual predictions. Eight imatinib PopPK model were selected for evaluating the model performance. A total of 145 plasma imatinib samples were collected from 43 adult patients diagnosed with CML and treated with imatinib. The PopPK model reported by Menon et al. had better performance than all other PopPK models. Menon et al. model was able to predict well for our clinical data where it had the relative mean prediction error percentage ≤ 20%, relative median absolute prediction error ≤ 30% and relative root mean square error close to zero. Based on this final model, we proposed a dosing nomogram for various weight groups, which could potentially help to maintain the trough concentrations in the therapeutic range.

A simple and sensitive liquid chromatography triple quadrupole mass spectrometry method for the determination of XL092 in monkey plasma and its application to pharmacokinetic study.

XL092 is a potent ATP-competitive inhibitor of multiple receptor tyrosine kinases that is undergoing clinical development for the treatment of lung cancer. In this study, an LC triple quadrupole mass spectrometry method was established to measure XL092 in monkey plasma. A Waters ACQUITY UPLC BEH C18 column was used for chromatographic separation. The mobile phase consisted of water containing 0.1% formic acid and acetonitrile with a gradient elution at the flow rate of 0.4 mL/min. Multiple reaction monitoring mode was used for quantitative analysis of XL092 in positive electrospray ionization. In the concentration range of 0.5-1000 ng/mL, XL092 showed excellent linearity in monkey plasma with a correlation coefficient greater than 0.995 (r > 0.995). The lowest limit of quantification was 0.5 ng/mL. The intra- and inter-day relative standard deviations were <9.99%, while the relative error ranged from -12.50% to 8.10%. The mean recovery was over 82.51%. XL092 was stable in monkey plasma after storage under certain conditions. The validated method was demonstrated to be selective, sensitive, and reliable, and has been successfully applied to the pharmacokinetic study of XL092 in monkey plasma. XL092 showed moderate short half-life (~3.81 h) and good oral bioavailability (80%).

Iruplinalkib (WX-0593) Versus Crizotinib in ALK TKI-Naive Locally Advanced or Metastatic ALK-Positive NSCLC: Interim Analysis of a Randomized, Open-Label, Phase 3 Study (INSPIRE)

BackgroundIruplinalkib (WX-0593) is a new-generation, potent ALK tyrosine kinase inhibitor (TKI) that has been found to have systemic and central nervous system (CNS) efficacy in ALK-positive NSCLC. We compared the efficacy and safety of iruplinalkib with crizotinib in patients with ALK TKI-naive, locally advanced or metastatic ALK-positive NSCLC. MethodsIn this open-label, randomized, multicenter, phase 3 study, patients with ALK-positive NSCLC were randomly assigned to receive iruplinalkib 180 mg once daily (7-d run-in at 60 mg once daily) or crizotinib 250 mg twice daily. The primary end point was progression-free survival (PFS) assessed by Independent Review Committee (IRC) per Response Evaluation Criteria in Solid Tumors version 1.1. Secondary end points included PFS by investigator, objective response rate (ORR), time to response, duration of response, intracranial ORR and time to CNS progression by IRC and investigator, overall survival, and safety. An interim analysis was planned after approximately 70% (134 events) of all 192 expected PFS events assessed by IRC were observed. Efficacy was analyzed in the intention-to-treat population. Safety was assessed in the safety population, which included all randomized patients who received at least one dose of the study drugs. This study is registered with Center for Drug Evaluation of China National Medical Products Administration (CTR20191231) and Clinicaltrials.gov (NCT04632758). FindingsFrom September 4, 2019, to December 2, 2020, a total of 292 patients were randomized and treated; 143 with iruplinalkib and 149 with crizotinib. At this interim analysis (145 events), the median follow-up time was 26.7 months (range: 3.7–37.7) in the iruplinalkib group and 25.9 months (range: 0.5–35.9) in the crizotinib group. The PFS assessed by IRC was significantly longer among patients in the iruplinalkib group (median PFS, 27.7 mo [95% confidence interval (CI): 26.3–not estimable] versus 14.6 mo [95% CI: 11.1–16.5] in the crizotinib group; hazard ratio, 0.34 [98.02% CI: 0.23–0.52], p < 0.0001). The ORR assessed by IRC was 93.0% (95% CI: 87.5–96.6) in the iruplinalkib group and 89.3% (95% CI: 83.1–93.7) in the crizotinib group. The intracranial ORR was 90.9% (10 of 11, 95% CI: 58.7–99.8) in the iruplinalkib group and 60.0% (nine of 15, 95% CI: 32.3–83.7) in the crizotinib group for patients with measurable baseline CNS metastases. Incidence of grade 3 or 4 treatment-related adverse events was 51.7% in the iruplinalkib group and 49.7% in the crizotinib group. InterpretationIruplinalkib was found to have significantly improved PFS and improved intracranial antitumor activity versus crizotinib. Iruplinalkib may be a new treatment option for patients with advanced ALK-positive and ALK TKI-naive NSCLC. FundingThis study was funded by Qilu Pharmaceutical Co., Ltd., Jinan, People’s Republic of China, and partly supported by the National Science and Technology Major Project for Key New Drug Development (2017ZX09304015).

Discovery of a potent and selective covalent threonine tyrosine kinase (TTK) inhibitor

Threonine tyrosine kinase (TTK) is a critical component of the spindle assembly checkpoint and plays a pivotal role in mitosis. TTK has been identified as a potential therapeutic target for human cancers. Here, we describe our design, synthesis and evaluation of a class of covalent TTK inhibitors, exemplified by 16 (SYL1073). Compound 16 potently inhibits TTK kinase with an IC50 of 0.016 μM and displays improved selectivity in a panel of kinases. Mass spectrometry analysis reveals that 16 covalently binds to the C604 cysteine residue in the hinge region of the TTK kinase domain. Furthermore, 16 achieves strong potency in inhibiting the growth of various human cancer cell lines, outperforming its relative reversible inhibitor, and eliciting robust downstream effects. Taken together, compound 16 provides a valuable lead compound for further optimization toward the development of drug for treatment of human cancers.

Systemic Therapies for HER2-Positive Advanced Breast Cancer.

Despite recent advances, HER2-positive advanced breast cancer (ABC) remains a largely incurable disease, with resistance to conventional anti-HER2 drugs ultimately unavoidable for all but a small minority of patients who achieve an enduring remission and possibly cure. Over the past two decades, significant advances in our understanding of the underlying molecular mechanisms of HER2-driven oncogenesis have translated into pharmaceutical advances, with the developing of increasingly sophisticated therapies directed against HER2. These include novel, more potent selective HER2 tyrosine kinase inhibitors (TKIs); new anti-HER2 antibody-drug conjugates; and dual epitope targeting antibodies, with more advanced pharmacological properties and higher affinity. With the introduction of adjuvant T-DM1 for incomplete responders to neoadjuvant therapy, fewer patients are relapsing, but for those who do relapse, disease that may be resistant to standard first- and second-line therapies requires new approaches. Furthermore, the risk of CNS relapse has not been abrogated by current (neo)adjuvant strategies; therefore, current research efforts are being directed towards this challenging site of metastatic disease. In this article, we review the currently available clinical data informing the effective management of HER2-positive breast cancer beyond standard first-line therapy with pertuzumab, trastuzumab, and taxanes, and the management of relapse in patients who have already been exposed to both these agents and T-DM1 for early breast cancer (EBC). We additionally discuss novel anti-HER2 targeted agents and combinations in clinical trials, which may be integrated into standard treatment paradigms in the future.

Design, synthesis and biological evaluation of potent epidermal growth factor receptor tyrosine kinase (EGFR-TK) inhibitors against resistance mutation for lung cancer treatment

In this study, we identified a newly synthesized compound 7o with potent inhibition on EGFR primary mutants (L858R, Del19) and drug-resistant mutant T790M with nanomolar IC50 values. 7o showed strong antiproliferative effects against EGFR mutant-driven non-small cell lung cancer (NSCLC) cells such as H1975, PC-9 and HCC827, over cells expressing EGFRWT. Molecular docking was performed to investigate the possible binding modes of 7o inside the binding site of EGFRL858R/T790M and EGFRWT. Analysis of cell cycle evidenced that 7o induced cell cycle arrest in G1 phases in the EGFR mutant cells, H1975 and PC-9, which resulted in decreased S-phase populations. Moreover, compound 7o induced cancer cell apoptosis in in vitro assays. In addition, 7o inhibited cellular phosphorylation of EGFR. In vivo, oral administration of 7o caused rapid tumor regression in H1975 xenograft model. Therefore, 7o might deserve further optimization as cancer treatment agent for EGFR mutant-driven NSCLC.

Safety and Efficacy of Bezuclastinib (CGT9486), a Novel, Highly Selective, Potent KIT D816V Tyrosine Kinase Inhibitor, in Patients with Advanced Systemic Mastocytosis (AdvSM): Results from Part 1 of the Phase 2 Apex Trial

Background: Systemic mastocytosis (SM) is a rare disease characterized by the aberrant proliferation of mast cells (MC). In about 95% of adult patients, SM is driven by a gain-of-function mutation (D816V) in exon 17 of KIT. Advanced SM (AdvSM) is a life-threatening form of SM and includes three subtypes: aggressive SM (ASM), SM with an associated hematologic neoplasm (SM-AHN), and Mast Cell leukemia (MCL). Bezuclastinib is an oral, potent, and selective tyrosine kinase inhibitor (TKI) with activity against KIT D816V. Preliminary results from the on-going Apex study in patients with AdvSM (NCT04996875) were presented previously (DeAngelo et al. [abstract] In: Blood (ASH) 2022; 140 (Supplement 1): 1512-13). Methods: Apex is a randomized Phase 2, open-label, multicenter trial in adult patients diagnosed with AdvSM per 2022 WHO criteria with a baseline serum tryptase of ≥20 ng/mL. In Part 1, patients were randomized 1:1:1:1 to bezuclastinib 50mg BID, 100mg BID, 200mg BID, or 400mg QD. Patients with a history of prior TKI therapy (e.g., avapritinib, midostaurin) are permitted in the trial. Data from Part 1 informed dose selection for Part 2 of the trial. The primary efficacy endpoint for this trial is overall response rate (complete response [CR], CR with incomplete hematologic recovery [CRh], partial response [PR] and clinical improvement [CI]) as assessed by a central review committee based on mIWG-MRT-ECNM response criteria. Results: As of April 2023, Part 1 was fully enrolled with 33 AdvSM patients. Patients were randomized to 50mg BID (n=8), 100mg BID (n=8), 200mg BID (n=8), or 400mg QD (n=9). Disease subtypes included ASM (n=7), MCL (n=2), and SM-AHN (n=24); AHN subtypes included CMML (n=18), MDS (n=3), MPN (n=1), and MDS/MPN-U (n=2). The majority of patients were male (64%), ECOG PS 0-1 (82%) and KITD816V positive at baseline (91%). At baseline, 67% of patients were TKI-naïve; 33% had prior midostaurin, and 15% had prior avapritinib. Median (range) BM MC burden, serum tryptase, and KIT D816V VAF at baseline were 30% (5-90), 163 ng/mL (35-1578), and 7% (0-47), respectively. Of the 33 patients enrolled, 25 patients (76%) had C-findings evaluable per mIWG-MRT-ECNM criteria; 20 patients (61%) were positive for SRSF2/ASXL1/RUNX1 mutation which are associated with poor survival in SM. Conclusion: Enrollment in Part 1 of the Apex trial is complete. Patients enrolled in Part 1 of the Apex trial are generally representative of the population of patients with AdvSM based on patient characteristics and markers of disease. Part 1 includes a small subset of patients with prior use of TKIs. Safety, clinical activity, and clinical objective response for all patients in Part 1 will be presented.

Tyrosine Kinase Inhibitor (TKI) Discontinuation in Non-Allografted Ph+ Acute Lymphoblastic Leukemia Patients, a Campus ALL Real-Life Study

Introduction. Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) patients are commonly treated with tyrosine kinase inhibitors (TKI) in combination with either steroids, chemotherapy and more recently also immunotherapy. In the past, allogeneic transplant (SCT) was considered the only curative option; however, with the introduction of more potent TKIs as well as immunotherapy this milestone is nowadays debated, mostly for patients who achieve a molecular response. Moreover, as in chronic myeloid leukemia (CML), it is becoming relevant to understand if patients may over time discontinue TKI treatment. For this purpose, it is pivotal to report the outcome of Ph+ ALL patients who, for any reason, stopped TKI treatment. Patients and Methods. Forty-seven adult Ph+ ALL patients treated since 1 January 2000, and who did not undergo a SCT, were retrospectively collected from 12 Italian centers participating to the Campus ALL network. Their treatment plan included a TKI +/- chemotherapy according to the center current practice and/or according to the ongoing national trial they were enrolled in. The median age was 63 years (20-84), 20 patients (43%) were males, 30 patients harbored a p190 transcript, 15 a p210 transcript and 2 had both transcripts. Twenty-six patients were treated within a trial, while 21 were off-protocol. For 32 patients, induction was based only on a TKI plus steroids, whereas the remaining 15 received a combination of a TKI plus chemotherapy (in 3 cases high intensity protocols such as the NILG (Northern Italian Leukemia Group) and HCVAD regimens, in 12 low dose chemotherapy). The reasons not to transplant patients were: donor unavailability (5), clinical decision, mainly due to age/unfitness (30), patient's refusal (4), and achievement of a molecular response (i.e. at least BCR-ABL/ABL ≤0.01%) (8). The median follow-up was 60 months, with a median overall survival (OS) not reached at the last follow-up and a median disease-free survival (DFS) of 12 years. At the last follow-up, 12/47 patients had experienced a relapse. At the end of the induction (i.e. after 3 months, at a median of +82 days, from treatment initiation), 27 patients had achieved a molecular response. Overall. a molecular response was obtained in 40/46 pts (data not available for 1 case) after a median of 5 month, and was associated with a significantly lower hazard of disease recurrence (HR=0.057, 95% CI: 0.006-0.51, p=0.011) after adjusting for gender, fusion protein, association with chemotherapy, CMR at 3 months. Results. TKI treatment was discontinued in 14 of the 47 patients evaluated. The reasons for discontinuation were either toxicity (6) or clinical/patient decision (8). Eight patients harbored a p190 transcript, 5 a p210 transcript and 1 carried both. At the time of discontinuation, the median age was 75 years (23-87) and patients had been on a TKI for a median of 57.5 months (8-160) prior to stopping treatment. For these cases, the median WBC at diagnosis were 8.6 x 10 9/l (2.1-306 x 10 9/l). In 7 patients the first TKI used was imatinib, in 3 dasatinib, in 3 ponatinib and in 1 nilotinib. All patients but 1 had achieved a molecular response before stopping treatment; the only patient who never achieved a molecular response prior to discontinuing the TKI had a rapid relapse (1 month). At the last follow-up, 9 cases were still in treatment-free remission (TFR), whereas 5 eventually relapsed after 1, 1, 4, 14 and 30 months, respectively. Re-challenge with a TKI led to a hematological and molecular response in 3 of the 5 patients. The remaining 2 patients, who had been previously heavily treated and whose TFR was of only 1 month, received salvage standard chemotherapy but eventually died from ALL progression. The median time of TFR for the entire cohort of 14 patients was 20.5 months (1-82). When considering only the 9 patients who remain off treatment, the median time of TFR was 29.5 months (7-82) (Table 1, Figure 1). Conclusions. We report the outcome of 14 Ph+ ALL patients who discontinued TKI treatment due to various reasons. Nine of them are still on TFR after more than 2 years at the last follow-up, reinforcing the concept that a TFR is feasible in selected adult Ph+ ALL patients. Of further relevance, TKI re-challenge was successful in 3/5 patients who relapsed, similarly to what observed in CML.

Zanubrutinib vs FCR in Fit Treatment-Naive Patients with Chronic Lymphocytic Leukemia: A Matching-Adjusted Indirect Comparison

Background: Fludarabine, cyclophosphamide, and rituximab (FCR) is the standard first-line therapy for fit (physically active, with no major health problems and normal renal function) treatment-naive patients with chronic lymphocytic leukemia (CLL) (Eichhorst et al. Ann Oncol. 2015). Due to the safety profile of FCR, including severe hematotoxicity, and severe infections, treatments with improved efficacy and safety are of interest (Hallek et al. Lancet. 2010; Fischer et al. Blood. 2016). Zanubrutinib, a highly specific and potent small-molecule inhibitor of Bruton tyrosine kinase, has been approved for treatment-naive patients with CLL. However, the comparative efficacy of zanubrutinib vs FCR in patients with CLL has not been investigated. Objective: The objective of this study was to determine the relative treatment effects of zanubrutinib vs FCR in fit treatment-naive patients with CLL. Methods: The CLL10 trial (NCT00769522; Eichhorst et al. Lancet Oncol. 2016) investigated FCR and bendamustine + rituximab (BR), while the SEQUOIA trial compared zanubrutinib to BR (NCT03336333; Tam et al. Lancet Oncol. 2022). Zanubrutinib and FCR were compared by means of an anchored matching-adjusted indirect comparison (MAIC) in which the BR arm of each trial served as a common comparator. Propensity score matching was conducted using patient-level data from SEQUOIA to adjust for differences between trial populations, per National Institute for Health and Care Excellence MAIC methods (Philippo et al. NICE DSU Technical Support Document 18. 2016). Progression-free survival (PFS), as assessed by the independent review committee, was then compared based on the matched patient populations. The selection of matching variables was based on literature review and consultation with clinical experts. As the indirect treatment comparison was anchored on the common comparator arm (BR), patient characteristics that are solely prognostic did not need to be incorporated. The core model included immunoglobulin heavy chain gene mutation, cytogenetic mutations (11q deletion), β2-microglobulin, Binet stage, and age. Geographic region, sex, creatinine clearance, Cumulative Illness Rating Scale (CIRS) score, Eastern Cooperative Oncology Group performance status (ECOG PS), and previous infections were tested in sensitivity analyses. Results: PFS was favorable with zanubrutinib vs FCR, and statistically significant differences were observed in the base case model (hazard ratio [HR], 0.41; 95% CI, 0.20-0.81; p-value=0.01). Sensitivity analyses showed significantly improved PFS with zanubrutinib when adding geographic region (HR, 0.43; 95% CI, 0.21-0.90; p-value=0.03), sex (HR, 0.44; 95% CI, 0.22-0.89; p-value=0.02), ECOG PS (HR, 0.30; 95% CI, 0.14-0.64; p-value&amp;lt;0.01), and previous infections (HR, 0.45; 95% CI, 0.22-0.93; p-value=0.03) to the base case set of matching variables. A sensitivity analysis incorporating CIRS (HR, 0.45; 95% CI, 0.16-1.24; p-value=0.12) showed only numerically favorable PFS with zanubrutinib, owing in part to the low effective sample size (ESS) in the expanded model. Similar results were obtained when creatinine clearance was added to the base case matching set of variables (HR, 0.52; 95% CI, 0.24-1.13; p-value=0.10). Conditional on the number of matching variables, ESS ranged from 174.1 in the core model to 64.05 in the analysis that included the CIRS score. Conclusion:Our findings suggest that zanubrutinib offers clinically meaningful benefits in PFS over FCR in fit treatment-naive patients with CLL. MAICs rely on reporting of relevant patient characteristics in published studies. In the current study, ZAP-70 methylation and TP53 mutation, which were considered treatment effect modifiers, were not reported in CLL10 and were not accounted for in the propensity model.

Retrospective Study to Evaluate Probability of MR4 Maintenance Following Frontline Nilotinib Dose De-Escalation after MR4 Achievement in the Patients with Chronic Myeloid Leukemia in Chronic Phase

Introduction: Nilotinib (NIL) is a potent second-generation tyrosine kinase inhibitor (TKI) approved for the treatment of newly diagnosed chronic myeloid leukemia (CML) patients (pts) in chronic phase, but reported to increase long-term toxicity such as cardiovascular (CV) risks. The ENESTfreedom study (Leukemia 2021) has reported 55% of treatment-free remission (TFR) rate after front line NIL discontinuation with a median 43.5 months of NIL treatment duration. Question still remains how to improve TFR rate after NIL frontline therapy. A potential solution is dose de-escalation (DESC) after MR4 achievement which could reduce the CV risk while extending MR4 duration prior to TFR attempt, thus increasing the chance of successful TFR attempt. DESTINY trial (Lancet Haematology 2019) had attempted TKI dose DESC to half of the standard dose for 12 months before stopping TKI therapy, reporting only 3 pts (2.4%) lost molecular response after TKI dose DESC in 125 pts who achieved molecular response with 4 log or deeper (MR4). However, 85% of this cohort is mainly treated with imatinib, limiting applying this experience in NIL treated pts. Accordingly, the present study attempted to evaluate the efficacy of NIL dose DESC following MR4 achievement based on real-world experience. Patients &amp; Method: We have retrospectively analyzed the outcome of adult pts with CML in chronic phase treated with NIL frontline therapy and achieved sustained MR4 ( BCR::ABL1 transcript ≤0.01%IS). From the pts treated with NIL frontline therapy, we identified the cases attempted NIL de-scalation after achievement of MR4. The molecular response after NIL de-escalation was closely monitored every 3 months using BCR::ABL1 qPCR. Molecular recurrence was defined as an increase in BCR::ABL1 transcript levels above MR4 on at least two consecutive occasions or a single increase in BCR::ABL1 transcript level above MR3 ( BCR::ABL1 transcript ≤0.1%IS). At any time, pts who lost MR3 had returned Nilotinib dose to 300 mg BID. Primary endpoint of the study was event-free survival (EFS) following NIL de-escalation, which was defined from NIL DESC starts to molecular recurrence or death from any cause. Results: We have identified 52 pts who started NIL as first line therapy for CML-CP under clinical practice. With median follow-up duration of 9 years (range:2-12 years), 33 patient (64%) remains on NIL at the last follow-up visit. In 33 pts on NIL treatment, with a median follow up duration of 8 years (range;2-12), 25 (76%) had attempted NIL DESC at median of 6 years (range; 1-10 years) after frontline NIL therapy start, of whom the median time from NIL start to MR4 achievement was 12 months (range: 5-50 months). The median time from first achievement of MR4 to NIL DESC starts was 50 months (range: 3-105 months), while the median time from NIL start to NIL DESC was 77 months (range: 13-121 months). At the latest follow up, only one patient experienced molecular recurrence at 3 months after DESC but regained MR3 in 9 months after re-escalation of NIL to 300mg BID. One patient died of cardiac arrest at 80 months after NIL DESC with other comorbidities of coronary artery disease, hypertension and diabetes. One patient discontinued NIL at 51 months post DESC and has sustained MR4 till last follow up. In the DESC group, the EFS at 3 years, 95% (69.5-99.3%). There is another case developed myocardial infarction while on DESC dose of NIL, who switched the treatment to Asciminib. Conclusion: Achieving early and sustained MR4 with frontline NIL treatment facilitates DESC approach without compromising molecular response and might promote the TFR rate by extending MR4 duration. This DESC strategy can bridge CML pts on NIL frontline therapy prior to NIL discontinuation for TFR attempt.

Frontline Combination of 3 rd Generation TKI Olverembatinib and Blinatumomab for Ph+/Ph-like ALL Patients

Background The combination of dasatinib and blinatumomab represented a chemotherapy-free treatment approach, which had been employed in the management of newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL). A recent study demonstrated that combination therapy of ponatinib with blinatumomab may achieve better efficacy, with a complete molecular response (CMR) rate of 87%. However, some patients required dose reduction or even discontinuation of ponatinib for the occurrence of cardiovascular adverse events. Olverembatinib, a potent third-generation tyrosine kinase inhibitor (TKI), showed both favorable tolerability and significant efficacy in patients with TKI-resistant chronic myeloid leukemia. But its effectiveness in ALL remained unaddressed. Our recent study, a frontline combination of Olverembatinib and PDT-ALL-2016 regime in Ph+ALL, had shown a promising outcome, achieving a complete molecular response (CMR) rate of 84.6% at day 90. Herein, we explored the clinical efficacy of the frontline combination of Olverembatinib and blinatumomab for the treatment of Ph+ and ABL-class Ph-like ALL. Methods From April 2022 to May 2023, 13 patients with Ph+/Ph-like ALL treated with olverembatinib (40mg once every other day) and blinatumomab (administered for a total of 2 weeks followed by 2 weeks of break) were enrolled (Figure 1a). Two patients (15.4%, 2/13) were in Ph-like ALL group with TEL-ABL and EBF1-PDGFRB fusion gene. Five patients (38.5%, 5/13), with a median age of 58 years old, were received ≥2 cycles and eight patients (61.5%, 8/13), with a median age of 34.5 years old, were treated with 1 cycle before HSCT. Result With a median follow-up of 7 months, all patients (100%, 13/13) achieved complete remission (CR) after one cycle of treatment. Among them, nine patients (72.7%, 9/13) achieved complete molecular remission (CMR) after one cycle, and ten patients (90.1%, 10/13) after two cycles. Notably, all patients (100%, 13/13) achieved CMR within three months of olverembatinib and blinatumomab treatment (Figure 1b). The 6-month overall survival (OS) rate was 100% and the 6-month event-free survival (EFS) rate was 87.5% (Figure 1 c and d). One patient with ABL mutation EE255V died due to relapse after HSCT. The regimen was overall well tolerated. For hematologic toxicity, one patient (7.7%, 1/13) experienced grade 1 neutrophil decrease. Regarding non-hematologic toxicity, five patients (38.4%, 5/13) developed infections during treatment, including COVID-19 and herpes zoster. Five patients (38.4%, 5/13) experienced decreased levels of immunoglobulins. Ten patients (76.9%, 10/13) experienced grade 1 cytokine release syndrome (CRS). Importantly, there were no interruptions in dosing of olverembatinib during treatment while no cardiovascular adverse events were observed. Conclusion This is the first report on the combination of olverembatinib with blinatumomab for the treatment of Ph+/Ph-like ALL. Among the 13 patients enrolled, a notable rate of CR and CMR was observed, which holds promise for improved long-term survival. Additionally, the combination of olverembatinib and blinatumomab exhibited minimal adverse events, both in terms of hematologic and non-hematologic toxicities. Notably, fewer cardiovascular adverse events that required discontinuation of treatment compared to ponatinib were observed. Altogether, these findings strongly indicated that combination therapy of olverembatinib with blinatumomab has the potential to become a new standard of care in the frontline treatment of Ph+/Ph-like ALL. However, further clinical trials are needed to definitively establish the efficacy of this treatment approach and validate the potential benefits. This research was supported by the National Natural Science Foundation of China(NFSC82170163, 81970147), Clinical Study of Nanfang Hospital(LC2016ZD009/2019CR012).

Gilteritinib and Venetoclax for Relapsed/Refractory FLT3-Mutated Acute Myeloid Leukemia - a Real-World Multicenter Retrospective Study

Introduction: Relapsed/Refractory (R/R) FLT3-mutated AML is a challenging clinical scenario with a dismal outcome. Gilteritinib, a selective and potent oral FLT3 tyrosine kinase inhibitor (TKI), is approved for treatment of FLT3 mutated R/R AML, and was shown to improve response rates and overall survival (OS) as compared to standard chemotherapy (Perl et al, NEJM 2019). However, remission rates and long-term survival with gilteritinib monotherapy are still unsatisfactory, highlighting the need for new therapies to improve patient outcomes. Recently, the combination of gilteritinib and venetoclax (Gilt-Ven) was shown to achieve a response rate of 75% in R/R FLT3 AML patients (Daver et al, JCO 2022). Data regarding Gilt-Ven based combinations in patients outside of clinical trials is lacking. We therefore aimed to investigate the characteristics and outcomes of real-world patients with R/R FLT-3 mutated AML treated with Gilt-Ven based combinations. Methods: A multicenter retrospective cohort study in seven academic centers in Israel. Demographic, clinical and treatment related data were collected. The decision to treat a patient with Gilt-Ven (with or without azacitidine) as well as dosing were at discretion of the treating physician. Results: Eighteen patients were treated with Gilt-Ven based therapies for FLT-3 mutated R/R AML between January 2018 and June 2023. Median follow-up time was 5 months (range 0-24). Median age at treatment initiation was 48 years (range 24-79). Twelve patients (66.7%) had relapsed disease, while 6 (33.3%) had refractory disease. Thirteen patients (72.2%) had a normal karyotype; two had complex karyotype and one had monosomal karyotype. Sixty-one percent had prior therapy with a FLT3 inhibitor, and 33% had prior venetoclax exposure. Eighty-eight percent received a prior intensive induction regimen and 61% had prior Allogeneic Hematopoietic Stem Cell Transplantation (AlloHSCT) (Figure 1A). Most patients received Gilt-Ven doublet, while 27% received Gilt-Ven in combination with other agents (three patients with azacitidine, one with low-dose cytarabine and one with FLAG-IDA). The median dose for gilteritinib was 120 (range, 80-120) mg and all patients received 400 mg venetoclax (or equivalent dose adjustment to azoles). Overall Response Rate (CR+CRi+MLFS) was 83%; Complete remission rate was 50% (Figure 1B). The median number of cycles was 1.5 (range 1-34) for the whole cohort. Five patients (27%) proceeded to alloHSCT. Of these, four patients required one course of Gilt-Ven, and one patient received 6 courses and proceeded to AlloHSCT after a subsequent relapse and another line of therapy. Median OS was not reached for all patients (range 6-NR), but was only 6 months (range 0-10) for patients who did not proceed to AlloHSCT. Hematologic adverse events were most common with 89% of patients experiencing grade 3/4 neutropenia; however, infections were relatively uncommon with only 17% of patients experiencing grade 3/4 Infection. Transaminitis grade 1/2 was observed in 38.9% of patients while no patient developed grade 3/4. No cases of differentiation syndrome were recorded. Conclusion: In a real-world setting, Gilt-Ven based therapy is effective for heavily pre-treated patients with FLT-3 mutated R/R AML, especially as a bridge to AlloHSCT.

Combinatorial Treatment Options for Highly Resistant Compound Mutations in the Kinase Domain of the BCR::ABL1 Fusion Gene

The introduction of tyrosine kinase inhibitor (TKI)-based therapies has dramatically changed the outcome in patients with chronic myeloid leukemia (CML) and Ph-positive acute lymphoblastic leukemia (Ph+ALL). However, the occurrence of point mutations in the kinase domain (KD) of the BCR::ABL1 fusion gene can impair or inhibit the efficacy of individual TKIs. In advanced phases of CML and in Ph +ALL, patients frequently develop compound mutations (CMs), defined as the presence of more than one mutation on the same BCR::ABL1 molecule in a leukemic cell, which are often highly or even completely resistant to any individual TKI. Some CMs respond to high doses of the currently most potent available TKI, ponatinib, but the dose-related toxicity is an important impediment. The most frequently occurring CMs, which include the gatekeeper mutation T315I, are often resistant to any currently available TKI. We performed in vitro analyses using a common cell line model based on Ba/F3 cells expressing a panel of 12 different CMs (V299L/G250E, V299L/E255V, V299L/F359V, F317L/Y253H, F317L/E255V, F317L/F359V, F359V/Y253H, T315I/M244V, T315I/G250E, T315I/E255K, T315I/E255V, T315I/F359V) in BCR::ABL1 constructs introduced into the cells by a transposon-mediated approach. The presence of single insertion copies of the mutant constructs was verified by FACS analysis to preclude skewed test results potentially caused by multiple copies of the mutant construct. The cells pre-tested in this way were exposed in vitro to different concentrations of various drugs including ponatinib combined with a number of other agents such as asciminib, hydroxyurea, palbociclib, venetoclax, ibrutinib, vodobatinib, and crizotinib. The drug concentrations tested corresponded to the spectrum of the respective dosing regimens used in the clinical setting. The cell viability assays performed indicated that CMs responding only to elevated concentrations of ponatinib could be suppressed by combinatorial treatment with lower concentrations of ponatinib and different other agents tested. Moreover, CMs displaying high levels of resistance to TKIs applied as single agents mostly revealed adequate in vitro responses to individual drug combinations with ponatinib, most commonly including asciminib, hydroxyurea or crizotinib. Only the most resistant CM constellation tested, T315I/F359V, failed to respond to the compounds investigated and showed a limited response to the combination of high concentrations of ponatinib with hydroxyurea. A good response of this CM in vitro was only achieved by a combination of ponatinib with a very high concentration of crizotinib indicating the need for further testing of additional candidate drugs for this constellation. Overall, combinatorial treatment of BCR::ABL1 CMs indicated that relatively low concentrations of the drugs used are capable of effectively inhibiting in vitro survival of mutant cells in most instances, which is important with regard to the expected toxicity of combinatorial treatment approaches. Since our earlier data indicated a good correlation between in vitro test results and clinical responses, our observations may serve as a basis for novel treatment options in patients with Ph +leukemias displaying challenging BCR::ABL1 KD-mutations. [This project was supported by an educational grant from Incyte Biosciences International Sàrl]

Tyrosine kinase inhibitors (TKIs) for ovarian cancer treatment: from organic to inorganic chemotherapeutics towards selectivity-a perspective overview.

Ovarian cancer (OC) is a lethal gynecologic cancer in industrialized countries. Treatments for OC include the surgical removal and chemotherapy. In the last decades, improvements have been made in the surgery technologies, drug combinations and administration protocols, and in diagnosis. However, mortality from OC is still high owing to recurrences and insurgence of drug resistance. Accordingly, it is urgent the development of novel agents capable to effectively target OC. In this respect, tyrosine kinase inhibitors (TKIs) may play an important role. Most of TKIs developed and tested so far are organic. However, owing to their chemical versatility, also metals can be exploited to design selective and potent TKIs. We provide a short and easy-to-read overview on the main organic TKIs with a summary of those that entered clinical trials. Additionally, we describe the potential of metal-based TKIs, focusing on this overlooked family of compounds that may significantly contribute towards the concept of precision-medicine.

Efficacy and Safety of Nintedanib in Patients with Interstitial Lung Disease with or without Systemic Sclerosis: A Meta-Analysis.

Nintedanib is a potent intracellular inhibitor of tyrosine kinases and modulates the pathways involved in the development of fibrosis. We assessed nintedanib efficacy and safety in interstitial lung disease (ILD) patients. We searched MEDLINE, EMBASE, and the Cochrane Controlled Trials Register to identify available articles (up to April 2022). We conducted a meta-analysis of randomized controlled trials (RCTs) examining nintedanib efficacy and safety in patients with ILD with or without systemic sclerosis (SSc). Meta-analysis of five RCTs including 2,470 patients with ILD (1,343 nintedanib group and 1,127 controls) revealed that the annual rate of change in forced vital capacity (FVC) was significantly lower in the ILD group than in the control group (standardized mean difference [SMD] = 0.336; 95% confidence interval (CI) = 0.256-0.416, P<0.001). Stratification by disease type showed a low annual rate of change in FVC in patients with and without SSc (SMD = 0.389, 95% CI=0.294-0.478, P<0.001; SMD=0.177, 95% CI=0.013-0.340, P<0.00). The incidence of serious adverse events did not differ between the nintedanib and placebo groups; however, adverse events (AEs) and withdrawals due to AEs were significantly higher in the nintedanib group than in the placebo group (SMD =2.365, 95% CI=1.673-3.343, P<0.001; SMD =1.740, 95% CI= 1.385-2.185, P<0.001). Nintedanib is effective for ILD with or without SSc. However, it increased the incidence of AEs and withdrawals due to AEs.