Third-generation Tyrosine Kinase Inhibitors Research Articles

Abstract CT282: MK-2870-004: A phase 3 study of MK-2870 (SKB264) versus chemotherapy for previously treated advanced or metastatic nonsquamous non-small-cell lung cancer (NSCLC) with EGFR mutations or other genomic alterations

Abstract Background: Trophoblast cell-surface antigen 2 (TROP2), a cell surface glycoprotein involved in the regulation of tumor growth and invasion, is broadly expressed and upregulated in several cancers, including NSCLC. MK-2870 (SKB264) is an antibody-drug conjugate (ADC) composed of the humanized anti-TROP2 monoclonal antibody, a hydrolytically cleavable linker, and the cytotoxic drug KL610023. MK-2870 has demonstrated encouraging antitumor activity and manageable toxicity in phase 1 and 2 studies of patients with solid tumors, including heavily pretreated EGFR-mutant NSCLC. We describe the design of the ongoing phase 3 MK-2870-004 study (NCT06074588) that will evaluate the efficacy and safety of MK-2870 vs chemotherapy for previously treated advanced or metastatic nonsquamous NSCLC with EGFR mutations or other genomic alterations. Trial design: The global, randomized, open-label, phase 3 MK-2870-004 study will enroll ~556 patients, including 456 with exon 19del or L858R EGFR mutations, and 100 with other genomic alterations. Eligible patients are aged ≥18 years with histologically or cytologically documented advanced (stage III not eligible for resection or curative radiation) or metastatic nonsquamous NSCLC with exon 19del or exon 21 L858R EGFR mutations or other genomic alterations in ALK, ROS1, BRAF V600E, NTRK, MET exon 14 skipping, or RET and those with less common EGFR mutations (exon 20 S768I, exon 21 L861Q, and/or exon 18 G719X). Patients must have progressive disease on or after 1 or 2 lines of prior tyrosine kinase inhibitor (TKI) therapy and a platinum-based therapy (may contain anti-PD-[L]1), measurable disease per RECIST v1.1, an available tumor sample, and adequate organ function. Prior EGFR TKI therapy must include a third-generation TKI for patients with T790M EGFR-mutant NSCLC. Patients with active central nervous system metastases or carcinomatous meningitis are ineligible, although those with previously treated and untreated stable brain metastasis are eligible for enrollment. Patients will be randomized (1:1) to MK-2870 4 mg/kg Q2W on Days 1, 15, and 29 of every 6-week cycle, or chemotherapy (docetaxel 75 mg/m2 Q3W or pemetrexed 500 mg/m2 Q3W) on Days 1 and 22 of every 6-week cycle. Randomization will be stratified by EGFR mutations with prior third generation TKI vs EGFR mutations with no prior third generation TKI vs other genomic alterations, brain metastasis (yes vs no), and TROP2 expression (low vs medium vs high). Dual primary endpoints are PFS (per RECIST v1.1 by blinded independent central review) and OS in patients with EGFR-mutant NSCLC. Key secondary endpoints include PFS and OS in all patients with NSCLC, ORR, DOR, patient-reported outcomes, and safety. Enrollment started in November 2023 and is currently ongoing. Citation Format: Federico Cappuzzo, Edward B. Garon, Myung-Ju Ahn, Shun Lu, Terufumi Kato, Enriqueta Felip, Parneet Cheema, Nicolas Girard, Mark Shamoun, Guoqing Wang, Bin Zhao, Rina Hui. MK-2870-004: A phase 3 study of MK-2870 (SKB264) versus chemotherapy for previously treated advanced or metastatic nonsquamous non-small-cell lung cancer (NSCLC) with EGFR mutations or other genomic alterations [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 CT282.

Efficacy of third-generation epidermal growth factor receptor-tyrosine kinase inhibitors in advanced NSCLC with different T790M statuses tested via digital droplet polymerase chain reaction ddPCR and next-generation sequencing

ABSTRACT Objectives We hypothesize that digital droplet polymerase chain reaction (ddPCR) would optimize the treatment strategies in epidermal growth factor receptor (EGFR) -tyrosine kinase inhibitors (TKIs) relapsed patients. In this study, we compared the efficacy of third-generation TKIs with various T790M statuses via ddPCR and next-generation sequencing (NGS). Methods NGS was performed on blood samples of patients progressed from previous EGFR-TKIs for resistance mechanism. T790M-negative patients received further liquid biopsy using ddPCR for T790M detection. Results A cohort of 40 patients were enrolled, with 30.0% (12/40) T790M-positive via NGS (Group A). In another 28 T790M-negative patients by NGS, 11 (39.3%) were T790M-positive (Group B) and 17 (60.7%) were T790M-negative (Group C) via ddPCR. A relatively longer progression-free survival (PFS) was observed in group A (NR) and group B (10.0 months, 95% CI 7.040-12.889) than in group C (7.0 months, 95%CI 0.000-15.219), with no significant difference across all three groups (p = 0.196), or between group B and C (p = 0.412). EGFR-sensitive mutation correlated with inferior PFS (p = 0.041) and ORR (p = 0.326), and a significantly lower DCR (p = 0.033) in T790M-negative patients via NGS (n = 28). Conclusion This study indicates that ddPCR may contribute as a supplement to NGS in liquid biopsies for T790M detection in EGFR-TKIs relapsed patients and help to optimize the treatment strategies, especially for those without coexistence of EGFR-sensitive mutation. Trial registration www.clinicaltrials.gov identifier is NCT05458726.

Brigatinib combined with cetuximab in the fifth-line treatment of non-small cell lung cancer with EGFR p.C797S mutation in critically ill patients: a report of two cases and literature review.

For critically ill patients with non-small cell lung cancer (NSCLC) in need of life-saving treatment, there is currently no reported evidence regarding the use of medication specifically targeting epidermal growth factor receptor (EGFR) p.C797S mutation, which is known to cause resistance to third-generation tyrosine kinase inhibitors (TKIs). Our report aims to investigate and explore treatment strategies to overcome resistance associated with EGFR p.C797S mutation in order to provide potential therapeutic options for these patients. Here, we reported two cases with NSCLC who initially harbored an EGFR-sensitive mutation and were both treated with osimertinib, a third-generation TKI. Next-generation sequencing tests conducted prior to the initiation of fifth-line therapy in critically ill patients revealed the presence of EGFR p.C797S mutations in both patients, suggesting acquired resistance. In the course of fifth-line therapy, the administration of a combination of brigatinib and cetuximab proved vital in saving critically ill patients, moderately extending their overall survival period. Our findings suggested that a combined regimen of brigatinib and cetuximab could serve as a potentially life-saving therapeutic strategy for critically ill patients with NSCLC, particularly those demonstrating EGFR p.C797S-mediated resistance. Further studies, however, are required to validate and expand upon these promising findings.

The Cardiovascular Event Risk Associated with Tyrosine Kinase Inhibitors and the Lipid Profile in Patients with Chronic Myeloid Leukemia.

Second- and third-generation tyrosine kinase inhibitors (TKIs) are now available to treat chronic-phase chronic myeloid leukemia (CP-CML) in the first and second line. However, vascular adverse events (VAEs) have been reported for patients with CML treated with some TKIs. We retrospectively evaluated the cumulative incidence (CI) and cardiovascular risk for 210 patients included in the Canarian Registry of CML. With a mean follow up of 6 years, 19/210 (9.1%) patients developed VAEs, all of whom presented at least one cardiovascular risk factor at diagnosis. The mean time to VAE presentation was 54 months from the start of TKI treatment. We found a statistically significant difference between the CI for nilotinib-naïve vs. nilotinib-treated patients (p = 0.005), between dasatinib-naïve and dasatinib-treated patients (p = 0.039), and for patients who received three lines of treatment with first-line imatinib vs. first-line imatinib (p < 0.001). From the multivariable logistic regression analyses, the Framingham risk score (FRS) and patients with three lines of TKI with first-line imatinib were the only variables with statistically significant hazard ratios for VAE development. Significant increases in HDL-C and total cholesterol may also be predictive for VAE. In conclusion, it is important to estimate the cardiovascular risk at the diagnosis of CML as it can help determine whether a patient is likely to develop a VAE during TKI treatment.

Allogeneic stem cell transplantation is still a highly curative therapy in adults with philadelphia chromosome-positive acute lymphoblastic leukaemia.

The application of tyrosine kinase inhibitors (TKIs) and novel immunotherapies has improved outcomes in patients with Ph + acute lymphoblastic leukaemia (ALL), and the issue of whether there is still a need for stem cell transplantation has become controversial. We performed a retrospective study to explore whether stem cell transplantation still held a place in patients with Ph + ALL if only imatinib and 2nd generation TKIs are available and affordable. A total of 292 patients were included. The median age was 38 years [range 14-64, IQR 28-48]. Patients receiving transplants (n = 216) had better rates of 4-year disease-free survival (DFS, 68% vs. 24%, P < .0001) and overall survival (OS, 72% vs. 47%, P < .0001) than those receiving continuous TKIs plus chemotherapy (TKI-chemo) (n = 76). In the multivariate analysis, male sex, WBC count ≥ 95 × 109/L and PLT count ≤ 154 × 109/L at diagnosis were significantly associated with poorer outcomes, and transplantation was significantly associated with favourable DFS and OS. In addition, the transplant outcomes were superior in any subgroup according to the number of risk variables. Furthermore, propensity score matching (PSM) analyses showed similar findings in the whole cohort and in age- and BCR-ABL1 level-based subgroups after the first or second consolidation. In conclusion, transplantation as a one-time procedure for adults with Ph + ALL patients remains important in countries lacking accessibility to third-generation TKIs or immunotherapies, regardless of the depth of the molecular response.

Synthesis and evaluation of a rociletinib analog as prospective imaging double mutation L858R/T790M in non-small cell lung cancer

Context: Imaging the mutation status of non-small cell lung cancer (NSCLC) using radiolabeled tyrosine kinase inhibitor (TKI) analogs has garnered interest due to their unique interactions with the target epidermal growth factor receptor (EGFR). Rociletinib is a third-generation TKI that selectively inhibits the activated EGFR L858R/T790M mutations while sparing the wild-type EGFR. Aims: To synthesize a rociletinib analog for radioiodination purposes and evaluate its affinity for EGFR L858R/T790M using molecular docking and in vitro cytotoxicity assay. Methods: The rociletinib analog, N-{3-[(4-{[4-(4-acetylpiperazin-1-yl)-2-methoxyphenyl]amino}-5-(trifluoromethyl)pyrimidine-2-yl)amino] -5-iodophenyl} acrylamide (I-RMFZ), was produced by adding iodine into the diaminophenyl group and changing the position of the trifluoromethyl group. A simulation of molecular docking was conducted using the AutoDock Vina software suite. IC50 of I-RMFZ was determined using a cell cytotoxicity assay. Results: I-RMFZ was successfully synthesized through multistep reactions. Molecular docking revealed that I-RMFZ interacts with the EGFR L858R/T790M mutation. Cytotoxicity assay demonstrated that I-RMFZ had a high selectivity towards EGFR L858R/T779M mutation. Conclusions: I-RMFZ is notable for radioiodination and is anticipated to be comparable with in vivo features of rociletinib. Thus, I-RMFZ can potentially be developed as an imaging agent for NSCLC through preclinical assay.

Mobocertinib: Mechanism of action, clinical, and translational science.

Epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations represent ~6%-12% of all EGFR-mutated non-small cell lung cancer (NSCLC) cases. First-, second-, and third-generation tyrosine kinase inhibitors (TKIs) have limited clinical activity against EGFR ex20ins mutations. Mobocertinib is a first-in-class oral EGFR TKI that selectively targets in-frame EGFR ex20ins mutations in NSCLC; accelerated approval in the United States was granted for the treatment of adult patients with locally advanced or metastatic NSCLC with EGFR ex20ins mutations whose disease has progressed on or after platinum-based chemotherapy. Accelerated approval was based on the results from the three-part, open-label, multicenter, pivotal phase I/II nonrandomized clinical trial (NCT02716116) that enrolled 114 patients with locally advanced or metastatic EGFR ex20ins mutation-positive NSCLC who were previously treated with platinum-based chemotherapy and received mobocertinib at the recommended dosage of 160 mg once daily. At the November 1, 2021, data cutoff date, the confirmed objective response rate per independent review committee (IRC) was 28%, median duration of response was 15.8 months, median progression-free survival per IRC was 7.3 months, and median overall survival was 20.2 months. The most common treatment-emergent adverse events were gastrointestinal- and skin-related. The phase III EXCLAIM-2 study evaluated mobocertinib versus chemotherapy as first-line therapy for locally advanced or metastatic EGFR ex20ins-positive NSCLC; however, the primary end point was not met, resulting in initiating voluntary withdrawal of mobocertinib worldwide. This mini-review article summarizes the mechanism of action, pharmacokinetic characteristics, key clinical trials, and clinical efficacy and safety data for mobocertinib.

Dose modification dynamics of ponatinib in patients with chronic-phase chronic myeloid leukemia (CP-CML) from the PACE and OPTIC trials

Ponatinib, the only approved all known-BCR::ABL1 inhibitor, is a third-generation tyrosine-kinase inhibitor (TKI) designed to inhibit BCR::ABL1 with or without any single resistance mutation, including T315I, and induced robust and durable responses at 45 mg/day in patients with CP-CML resistant to second-generation TKIs in the PACE trial. However, cardiovascular toxicities, including arterial occlusive events (AOEs), have emerged as treatment-related AEs within this class of TKIs. The OPTIC trial evaluated the efficacy and safety of ponatinib using a novel, response-based, dose-reduction strategy in patients with CP-CML whose disease is resistant to ≥2 TKIs or who harbor T315I. To assess the dose-response relationship and the effect on the safety of ponatinib, we examined the outcomes of patients with CP-CML enrolled in PACE and OPTIC who received 45 mg/day of ponatinib. A propensity score analysis was used to evaluate AOEs across both trials. Survival rates and median time to achieve ≤1% BCR::ABL1IS in OPTIC were similar or better than in PACE. The outcomes of patients with T315I mutations were robust in both trials. Patients in OPTIC had a lower exposure-adjusted incidence of AOEs compared with those in PACE. This analysis demonstrates that response-based dosing for ponatinib improves treatment tolerance and mitigates cardiovascular risk.

ITGB1 and DDR activation as novel mediators in acquired resistance to osimertinib and MEK inhibitors in EGFR-mutant NSCLC

Osimertinib is a third-generation tyrosine kinase inhibitor clinically approved for first-line treatment of EGFR-mutant non-small cell lung cancer (NSCLC) patients. Although an impressive drug response is initially observed, in most of tumors, resistance occurs after different time and an alternative therapeutic strategy to induce regression disease is currently lacking. The hyperactivation of MEK/MAPKs, is one the most common event identified in osimertinib-resistant (OR) NSCLC cells. However, in response to selective drug pressure, the occurrence of multiple mechanisms of resistance may contribute to treatment failure. In particular, the epithelial-to-mesenchymal transition (EMT) and the impaired DNA damage repair (DDR) pathways are recognized as additional cause of resistance in NSCLC thus promoting tumor progression. Here we showed that concurrent upregulation of ITGB1 and DDR family proteins may be associated with an increase of EMT pathways and linked to both osimertinib and MEK inhibitor resistance to cell death. Furthermore, this study demonstrated the existence of an interplay between ITGB1 and DDR and highlighted, for the first time, that combined treatment of MEK inhibitor with DDRi may be relevant to downregulate ITGB1 levels and increase cell death in OR NSCLC cells.

The Impact of Pretransplant Use of Tyrosine Kinase Inhibitors on Allogeneic Stem Cell Transplantation in Patients with Chronic Myeloid Leukemia-A Single-institution Retrospective Study.

Objective Chronic myeloid leukemia (CML) is a malignant hematological disorder, and allogeneic stem cell transplantation (allo-SCT) was its only curative treatment until the introduction of tyrosine kinase inhibitors (TKIs). Allo-SCT is still considered for CML patients who are resistant to TKIs and in an advanced phase. Currently, second- and third-generation (2/3 G) TKIs are typically incorporated into the first-line treatment of CML. However, the impact of 2/3 G TKIs on subsequent allo-SCT remains unclear. We therefore evaluated the effect of 2/3 G TKIs on allo-SCT. Methods We retrospectively evaluated the effect of pretransplant therapy with TKIs on the outcome of allo-SCT for CML using clinical data at our institution. Patients or Materials Thirty-two CML patients who received their first allo-SCT procedure at our institute from 2001 to 2020 were included. We divided the patients into three subgroups based on TKI treatment before allo-SCT. Patients receiving no TKIs, only imatinib (IM), and 2/3 G TKIs were classified into the Non-TKI, IM, and 2/3 G TKI groups, respectively. Results In a univariate analysis, the pretransplant use of 2/3 G TKIs was significantly associated with a higher 5-year overall survival (91.7%) and relapse-free survival (75.0%) than the use of IM (37.5% and 12.5%) in patients presenting with or progressing to the advanced phase. In addition, pretransplant use of 2/3 G TKIs did not increase the incidence of graft-versus-host disease (GVHD). Conclusions We demonstrated that the pretransplant use of 2/3 G TKIs was safe and improved the outcome of CML patients who presented with or progressed to the advanced phase without increasing the frequency of GVHD.

Skin reactions to tyrosine kinase inhibitors in pediatric patients with chronic myeloid leukemia.

Cutaneous adverse events are commonly reported in adult patients with chronic myeloid leukemia (CML) receiving tyrosine kinase inhibitors (TKIs); however, little is known about the cutaneous reactions in children receiving TKIs for CML. As pediatric patients may require lifelong TKI therapy, it is essential to understand the wide range of potential cutaneous toxicities. We examined all case studies, cohort studies, and clinical trials in PubMed/MEDLINE and Embase that reported cutaneous reactions to first-, second-, and third-generation TKIs in children 18 years or younger with CML. This review article focuses on the TKI drug types and doses, patient demographic characteristics, features of skin reactions, and clinical outcomes.

A narrative review of antibody-drug conjugates in EGFR-mutated non-small cell lung cancer.

In the past 15 years, non-small cell lung cancer (NSCLC) treatment has changed with the discovery of mutations and the development of new targeted therapies and immune checkpoint inhibitors. Epidermal growth factor receptor (EGFR) was the first mutation in NSCLC to have a drug that was FDA-approved in 2013. Osimertinib, a third-generation tyrosine kinase inhibitor, is approved as first-line therapy for advanced NSCLC and in the adjuvant setting for Stage IB-IIIA resected NSCLC. However, resistance to osimertinib is inevitably an issue, and thus patterns of resistance to EGFR-mutated NSCLC have been studied, including MET amplification, EGFR C797X-acquired mutation, human epidermal growth factor 2 (HER2) amplification, and transformation to small cell and squamous cell lung cancer. Current management for EGFR-mutated NSCLC upon progression of EGFR TKI is limited at this time to chemotherapy and radiation therapy, sometimes in combination with the continuation of osimertinib. Antibody-drug conjugates (ADCs) are made up of a monoclonal antibody linked to a cytotoxic drug and are an increasingly popular class of drug being studied in NSCLC. Trastuzumab deruxtecan has received accelerated FDA approval in HER2-mutated NSCLC. ADCs offer a possible solution to finding a new treatment that could bypass the intracellular resistance mechanism. In this review article, we summarize the mechanism of ADCs and investigational ADCs for EGFR-mutated NSCLC, which include targets to MET amplification, HER3, Trop2, and EGFR, along with other ADC targets being investigated in NSCLC, and discuss future directions that may arise with ADCs in EGFR-mutated NSCLC.

Comparing efficacy and safety of upfront treatment strategies for anaplastic lymphoma kinase-positive non-small cell lung cancer: a network meta-analysis

Aim: This article is based on our previous research, which was presented as a post at the Congress Aiom 2022 Congress and published in Tumori Journal as Conference Abstract (Tumori J. 2022;108:1–194. doi: 10.1177/03008916221114500). In this paper, a comprehensive presentation of all the achieved results is provided. Several tyrosine kinase inhibitors (TKIs) have been investigated to treat patients with anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC). However, direct comparisons between these TKIs are lacking, with many only being compared to crizotinib. To address this gap, a network meta-analysis was conducted to compare the efficacy and safety of various first-line systemic therapies for ALK-positive NSCLC. Methods: A thorough search of PubMed, Embase, and Cochrane Library was performed to identify randomized controlled trials (RCTs) published between January 01, 2000 and April 01, 2022, and included trials that investigated upfront treatments for this molecular subgroup and reported overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and adverse events (AEs) of grade 3 or higher (grade ≥ 3 AEs). Results: The analysis included 9 RCTs with 2,443 patients receiving eight different treatments: alectinib (at two different dosages), brigatinib, ceritinib, crizotinib, ensartinib, lorlatinib, and chemotherapy. Second and third-generation TKIs significantly prolonged PFS compared to crizotinib, with lorlatinib having the highest probability of yielding the most favorable PFS, followed by alectinib (300 mg or 600 mg). However, only alectinib has been shown to significantly prolong OS compared to crizotinib to date. Lorlatinib appears superior in reducing the risk of central nervous system (CNS) progression, followed by alectinib 600 mg. Ceritinib had the highest rate of AEs, followed by lorlatinib and brigatinib. Conclusions: Based on the network meta-analysis, alectinib and lorlatinib emerged as the most promising upfront treatment options. These treatments provide prolonged disease control while maintaining an acceptable safety profile.

Ponatinib-induced dilated cardiomyopathy: a case report

Ponatinib is a third-generation tyrosine kinase inhibitor with potent efficacy in the treatment of acute and chronic leukemia. Despite having an effective and sustained activity in all BCR-ABL1 mutations, it may cause cardiovascular adverse effects. Here we report a 56-year-old male patient with Chronic myeloid leukemia and no prior cardiac disorder who developed acute heart failure under ponatinib treatment. Guideline-recommended medical treatment for heart failure was initiated. Coronary angiography to exclude ischemic heart disease revealed no coronary stenosis. Cardiac magnetic resonance imaging showed findings consistent with non-ischemic dilated cardiomyopathy. After interruption of ponatinib treatment, cardiac evaluation showed improvement in left ventricular ejection fraction. Patients on Ponatinib therapy should be closely monitored for signs and symptoms of heart failure.

Olverembatinib (HQP1351) Enhances Antitumor Effects of Chemotherapy in Philadelphia Chromosome-Positive (Ph⁺) Acute Lymphoblastic Leukemia (ALL)

Introduction Ph⁺ ALL is the most common subtype of B-cell- (B-) ALL in adults. BCR-ABL1 tyrosine kinase inhibitors (TKIs) are effective against chronic myeloid leukemia (CML) cells. However, treatment with TKIs fails to maintain disease remission in Ph⁺ B-ALL. Although the complete hematologic remission rate is very high, cytogenetic and molecular remission rates are low, so that TKIs are still considered as complements to chemotherapy and bridges to allogeneic stem cell transplantation. Olverembatinib is a novel, third-generation TKI with more potent activity against BCR-ABL1 and overcomes various resistant mutations, including the “gatekeeper” T315I, which confers resistance against all first- and second-generation TKIs. The aim of this study was to assess whether olverembatinib combined with chemotherapeutic agents vincristine or doxorubicin can promote anti-cancer effects in Ph⁺ ALL cells and explore the potential mechanism of action of the combinations. Methods Cell-based antiproliferation assays to evaluate the activities of olverembatinib alone or in combination with vincristine or doxorubicin were conducted using the CellTiter-Glo® Luminescent Cell Viability assay kits. Drug induced cell apoptosis was measured by flow cytometry. Potential mechanism of action analysis was conducted using western blot to evaluate the protein expression involved in BCR-ABL1 and apoptosis signaling pathways. Results Cell-based antiproliferation studies showed synergistic activity of olverembatinib in combination with vincristine or doxorubicin in Ph⁺ ALL SUP-B15 cells compared with single agents after 72 hours of treatment. The percentage of apoptotic cells induced by 24-hour treatment of olverembatinib (100 nM), vincristine (300 nM), and the combination were 27.7%, 27.2%, and 40.7%, respectively, while the percentage of apoptotic cells induced by 24-hour treatment of doxorubicin (100 nM) alone and in combination with olverembatinib (100 nM) were 35.3 and 74.1, respectively (apoptotic cells % in DMSO control group is 6.74). The combination significantly increased cell apoptosis compared with single agents ( p &amp;lt; 0.0001). Mechanistically, the combination of olverembatinib with vincristine showed synergistic effects in inhibiting protein expression and phosphorylation of BCR-ABL1, and downstream signal transducer and activator of transcription 5 (STAT5). The synergistic effects were also seen in decreased phosphorylation of AKT and ERK1/2. In addition, the combination significantly decreased protein levels of antiapoptotic MCL-1, BCL-2, and BCL-xL and increased protein levels of proapoptotic BAX and p53 upregulated modulator of apoptosis (PUMA) in a dose-dependent manner, which led to marked augmentation of cleavage of caspase-3 and poly (ADP-ribose) polymerase 1 (PARP). A similar pattern was also observed when olverembatinib was combined with doxorubicin. Conclusions Olverembatinib, a novel, third-generation TKI, in combination with chemotherapeutic agents vincristine or doxorubicin decreased MCL-1, BCL-2, and BCL-xL and increased BAX and PUMA in a dose-dependent manner, the combinations have demonstrated synergistic antitumor effects by enhancing apoptosis and antiproliferation in Ph⁺ ALL cells, which may provide an alternative approach for treatment of patients with Ph⁺ ALL.

The Promising Third-Generation TKI Olverembatinib in Adult BCR::ABL1-Positive Acute Lymphoblastic Leukemia with T315I Mutation and Relapsed/Refractory Disease

Background Olverembatinib (HQP1351) is a novel third-generation tyrosine kinase inhibitor (TKI) that has shown remarkable efficacy and safety in chronic myeloid leukemia (CML). Still, few reports are available on BCR::ABL1-positive acute lymphoblastic leukemia (BCR::ABL1+ ALL). We first reported the early encouraging outcome of olverembatinib in BCR::ABL1+ ALL patients (pts) with T315I mutation or disease progression last year. Here, we enlarged the sample size and included a case of CML in lymphoid blast phase (CML-LBP) who also benefited from olverembatinib to a certain extent. Methods In this observational study, we retrospectively enrolled BCR::ABL1+ ALL or CML-LBP pts with T315I mutation, disease progression, or intolerant to previous TKIs in our institution from Dec. 2021 to May 2023. All pts received olverembatinib monotherapy (40mg qod) or combination therapy. Efficacy was assessed by CR rate, MRD negative (MRD &amp;lt;10 -4) rate by multiparameter flow cytometry (MFC), CMR (BCR-ABL1 transcript&amp;lt;10 -5) rate by RT-qPCR, as well as the survival data. PFS and OS were both calculated from the start of olverembatinib. Adverse events (AEs) were assessed and graded according to CTCAE v5.0. Results Totally, 30 pts with BCR::ABL1+ ALL (n=29) or CML-LBP (n=1) were analyzed. Among 29 BCR::ABL1+ ALL pts (median age of 60 years [range, 23-76]), 14 were in CR with molecular R/R disease, including 1 with MRD only detected by RT-qPCR. While the other 15 had hematological R/R disease, including 4 with central nervous system leukemia. T315I mutation was detected in 23 pts, including 8 with additional mutations. The baseline characteristics are detailed in Table 1. As for the 23-year-old female pt with CML-LBP, dasatinib was switched to olverembatinib when T315I, E255K, and E255V mutations were detected. T315I and E255V were eliminated rapidly after 1-month treatment of olverembatinib, while E255K still existed. At present, the patient maintained in CR, and blinatumomab will be used for MRD clearance before allo-HSCT. She was only included in the safety analysis. Among 14 pts with molecular R/R disease, 61.5% and 50% achieved MRD flow negativity and CMR with a median time of 1.3 months (range, 0.8-4.4) and 1.2 months (range, 0.9-4.4), respectively. Among 15 pts with hematological R/R disease, 80%, 53.3%, and 46.7% achieved CR/CRi, MRD flow negativity, and CMR, with a median time of 1 month (range, 0.2-2.5), 1 month (range, 0.2-3.3) and 2.1 months (range, 0.7-4.6), respectively. Totally, 8 pts underwent allo-HSCT with a median age of 48.5 years (range, 23-60), of which 6 pts achieved CMR before allo-HSCT, and all attained persistent CMR after allo-HSCT. By June 15, 2023, with a median follow-up time of 9.1 months (range, 1.7-16) in BCR::ABL1+ ALL pts, the median PFS was 7.8 months, and the median OS was not reached. For molecular R/R pts, the median PFS and OS were not reached, and for hematological R/R pts, the median PFS and OS were 6.5 and 8.6 months. MRD flow negativity or CMR responders had significantly better PFS and OS (PFS: p&amp;lt;0.001, p&amp;lt;0.001; OS: p&amp;lt;0.001, p&amp;lt;0.001), and bridging allo-HSCT after olverembatinib-based therapy showed a significant survival superiority (PFS: p=0.001; OS: p=0.017). Among the 23 pts with T315I mutation, the MRD flow negativity rate in pts with T315I single mutation was significantly higher than those with additional mutations (p=0.008), and the CMR rate tended to be better (p=0.089). Meanwhile, pts with T315I single mutation showed significant improvements in PFS and OS (Figure 1). As for safety analysis, the olverembatinib-based therapy was well-tolerated. Most non-hematological AEs were G1-2, and most G3-4 AEs were hematological, possibly related to chemotherapy. The incidence of G3-4 cardiovascular AEs was 6.7%. Five elderly pts (median age of 72 years [range, 63-76]) had temporary treatment suspension or dose reduction. No permanent discontinuation or death related to olverembatinib was observed. Conclusion This study further confirmed the efficacy of olverembatinib-based therapy in Chinese adults BCR::ABL1+ ALL pts with T315I mutation or R/R disease, especially in those with T315I single mutation. In addition, bridging allo-HSCT after deeper molecular remission could further improve survival. The safety profiles were manageable, but there is still a need to explore the optimal dose in elderly pts.

Olverembatinib Combined with Venetoclax and Reduced-Intensity Chemotherapy for Patients with Newly Diagnosed Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia: Early Results from a Phase II Study

Background The combination of olverembatinib (HQP1351), a novel third-generation tyrosine kinase inhibitors (TKIs), with venetoclax generated high response rates in patients with relapsed/refractory Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL). However, the efficacy and safety of these two agents-based regimens as frontline treatment remains unknown. Methods This is a single-arm phase II study (NCT05594784) that enrolled patients (pts) ≥ 14 years (yrs) of age with newly diagnosed Ph + ALL. Pts were required to have an ECOG performance score ≤ 2 and adequate organ function. Pts with accelerated phase or blastic phase of chronic myeloid leukemia were excluded. Pts were treated with a combination of venetoclax (100 mg d1, 200 mg d2, 400 mg d3-28), olverembatinib 40 mg once every continuously other day, vincristine 1.4 mg/m 2 (maximum dose 2 mg) on day 1, 8, 15, 22, and prednisone 60 mg/m 2 on day 1-14; 40 mg/m 2 on day 15-28 in cycle 1. In cycle 2-3, oral treatment with venetoclax 400 mg × 7 days, olverembatinib once every other day continuously and prednisone 60 mg/m 2 × 7 days was administrated in the form of outpatient treatment (Figure 1A). Cycles were repeated every 28 days. Olverembatinib 40 mg once every other day was given during cycle 1 and was reduced to 30 mg once every other day for pts achieving a complete molecular response (CMR). Routine triple intrathecal injection (methotrexate 10 mg, cytarabine 50 mg, and dexamethasone 10 mg) was performed to prevent central nervous system involvement. The selection of subsequent treatment was determined based on the patient's molecular response at 3 months and the availability of donor. The primary end point of this study was the CMR rate at 3 months. CMR was defined as undetectable BCR:ABL1 transcripts by using RT-PCR method with sensitivity of 0.001%. Major molecular response (MMR) was defined as more than 3-log reduction of BCR:ABL1 transcripts. Results From August 2022 to April 2023, a total of 31 pts were enrolled. All pts completed 3 cycles of treatment and could be assessed for the primary end point. Th data cutoff date was 25 th July 2023 with a median follow-up time of 5.8 months. The median age was 40 years (range, 20-66 years) and males accounted for 58.1%. Twenty-three pts (74.2%) expressed the p190 transcript and 8 pts (25.8%) expressed the p210 transcript. The median expression level of BCR:ABL1 was 96.33% (range, 70.79%-175.39%). All patients achieved CR at the end of cycle 1 and no tumor lysis syndrome or treatment-related deaths occurred. Molecular response at the end of cycle 1 was CMR in 17 patients (54.8%), MMR in 8 (25.8%), and less than MMR in 6 (19.4%). Molecular response at 3 months was CMR in 19 patients (61.3%), MMR in 10 (32.3%), and less than MMR in 2 (6.5%) (Figure 1B). Of the 10 pts with MMR at 3 months, 8 pts had BCR:ABL1 transcript levels fluctuating between 0.001% and 0.01%. No patients developed relapses or deaths at the last follow-up. The regimen was well-tolerated and safe. Most side effects were grade 1-2. The demand for transfusion and the incidence of infections significantly decreased compared to our historic data treating with intensive chemotherapy plus TKIs. No patient discontinued olverembatinib or venetoclax due to toxicity. Conclusion The combination of olverembatinib and venetoclax with reduced-intensity chemotherapy is a safe and effective regimen in patients with newly diagnosed Ph + ALL. The regimen results in high rates of CMR in the absence of intensive chemotherapy or immunotherapy.

Olverembatinib (HQP1351) Combined with Chemotherapy Is an Effective and Safe Treatment in Patients with Philadelphia Chromosome-Positive (Ph +) Acute Lymphoblastic Leukemia (ALL) and Chronic Myeloid Leukemia in Lymphoid Blast Phase (CML-LBP) That Failed TKI-Based Regimens

Background The prognosis of relapsed or refractory (R/R) Philadelphia Chromosome-Positive (Ph+) acute lymphoblastic leukemia (ALL) and TKI-resistant chronic myeloid leukemia in lymphoid blast phase (CML-LBP) remains poor, with lower rates of complete remission (CR) and shorter durations of response. Olverembatinib is a novel third-generation tyrosine kinase inhibitor (TKI) that has been demonstrated to effectively target a wide range of BCR::ABL1 kinase mutations, especially T315I, in patients with CML in the chronic or accelerated phase resistant to either imatinib or second-generation TKIs. However, data on olverembatinib-based regimens in R/R Ph+ ALL and CML-LBP are limited. Here, we report the efficacy and safety of olverembatinib, combined with chemotherapy, in patients with Ph+ ALL or CML-LBP that failed prior TKI-based therapies. Methods A retrospective study was conducted in adults with Ph + ALL or CML-LBP who failed imatinib- or second-generation TKI-based chemotherapy and subsequently received olverembatinib-based chemotherapy. Per NCCN 2023 guidelines: refractory disease was defined as CR not achieved at the end of induction; relapsed disease, reappearance of blasts in the blood or bone marrow (&amp;gt; 5%) or any extramedullary site after CR; molecular resistance, persistent or rising BCR::ABL1 transcript (&amp;gt; 1-log) by real-time quantitative polymerase chain reaction (RT-qPCR); and complete molecular response (CMR), BCR::ABL1 transcript &amp;lt; 0.01% by RT-qPCR. The primary endpoints of this study were CR rates in R/R patients and CMR rates in molecular-resistant patients. Results From February 2022 to May 2023, 31 patients were included in this study, including 24 (77%) with TKI-based chemotherapy-failed Ph + ALL; 7 (23%) with TKI-resistant CML-LBP; 15 (48%) with R/R disease; and 16 (52%) with molecular-resistant disease. A total of 17 (57%) patients were male, and the median (range; IQR) age was 46 (20-72; 30-64) years. Among 30 patients screened for BCR::ABL1 kinase domain mutations before administration of olverembatinib, 6 (19%) had no mutations; 15 (48%) had T315I; and 9 (29%) had other mutations, including E255K (n = 2), G250E(n = 2), D241E (n = 1), Y253H (n = 1), F317L (n = 1), F359C(n = 1), and Y253Fplus M351T (n = 1). The 15 R/R patients (11, Ph + ALL; 4, CML-BP) received olverembatinib 30 or 40 mg on alternate days combined with VP (vindesine 4 mg once per week for 4 weeks and prednisone 1 mg/kg for 3 weeks and tapered at the fourth). A total of 13 (86%) patients achieved CR after 4-week induction therapy. At a median (IQR) follow-up of 8 (4-13) months, 5 patients received allogeneic transplantation in CR, and were alive in CMR. A total of 8 patients received olverembatinib-based consolidation chemotherapy of either VP (n = 4) or hyper-CVAD (n = 4) after achieving CR. Six patients relapsed, of whom 4 died, and 1 remained in CMR. The 1-year relapse-free survival (RFS) and 1-year survival rates were 52% (95% CI, 21-83) and 68% (95% CI, 37-98), respectively. Among the 16 patients with molecular resistance to TKI-based chemotherapy (imatinib [n = 4]; dasatinib [n = 9]; flumatinib [n = 3]), 2 received olverembatinib monotherapy, 7 olverembatinib plus VP, and 7 hyper-CVAD, of whom 8 received subsequent allogeneic transplantation. At a median (IQR) follow-up of 9 (5-11) months, 1 of the patients receiving olverembatinib monotherapy progressed to hematologic relapse and was switched to CAR T-cell therapy; the other patient did not achieve CMR and underwent transplantation. Of the 14 patients receiving olverembatinib plus chemotherapy, 7 (50%) achieved CMR and 3 (21.4%) progressed to relapse, of whom 1 had hematological relapse and 2 developed central nervous system leukemia (CNSL) with bone marrow remission. A total of 7 patients received allogeneic transplantation, of whom 3 achieved and 4 did not achieve CMR before transplantation. After transplantation, all the 7 patients were in CMR except one who developed CNSL. The 1-year RFS and survival rates were 67% (95% CI, 42-91) and 93% (95% CI, 79-100), respectively. Among all patients, hematologic adverse events were readily manageable. Treatment-related nonhematologic severe adverse events were observed in 3 patients, including (each) stable angina pectoris, severe pneumonia, and fatal Klebsiella sepsis. Conclusions Olverembatinib-based chemotherapy is effective and safe in patients with R/R and molecular resistant Ph + ALL or CML-LBP.

Dynamic Changes in ABL1 Kinase Domain Mutations and Comparative Efficacy of Third-Generation Tyrosine Kinase Inhibitors across Different Stages in Acute Lymphoblastic Leukemia and Chronic Myeloid Leukemia Blast Crisis Patients

*Drs.Zixuan Li and Danyue Peng contributed equally. Drs.Mei Hong and Qiuling Wu are co-corresponding authors Background The development of first-generation and second-generation tyrosine kinase inhibitors (TKIs) has played a crucial role in the treatment of Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) and chronic myeloid leukemia (CML). However, the emergence of mutations in the kinase domain (KD) of BCR-ABL1 has increasingly compromised the efficacy of TKIs and become the primary cause of TKI resistance. Testing BCR-ABL1 KD mutations in early phase accurately is of great value in predicting response and guiding therapeutic decisions. Next-generation sequencing (NGS) provided a more comprehensive and elaborate understanding of mutation status. Third-generation (3G) TKI has been designed to overcome resistance problems caused by BCR-ABL1 KD mutations, and it exhibited unique pharmacological profiles and response patterns relative to different mutations and disease characteristics. Therefore, the potential clinical relevance of mutations detected by NGS and the efficacy of 3G TKI are worth exploring. Methods NGS was used to analyze the dynamic changes of both clinically unreported mutations and reported resistant mutations in the ABL1 KD during three stages of the disease course (pretreatment, remission, and relapsed periods) in Ph+ ALL (n = 97) and chronic myeloid leukemia blast crisis (CML-BP) (n = 21) patients. Meanwhile, the comparative efficacy of three generations of TKIs in Ph+ ALL (n = 92) and CML-BP (n = 23) and the relationship between ABL1 KD mutations and different TKI selection were analyzed. Results In Ph+ ALL patients, single ABL1 KD unreported mutations were detected in 30.49% of patients before therapy and 39.73% in remission, which accounted for the highest proportion among other mutation types. Conversely, single ABL1 KD resistant mutations were found to be the most prevalent (54.5%) in relapsed patients ( P &amp;lt; 0.0001). Logistic analysis revealed that the presence of F401V/L in untreated Ph+ ALL patients was associated with a higher risk of relapse ( P &amp;lt; 0.1). Furthermore, through analyzing patients who received TKI treatment, we observed that 3G TKIs like olverembatinib exhibited advantages in prognosis, including achieving deep molecular response, rapid remission reduction, and decreased relapse probability, for both newly diagnosed and relapsed Ph+ ALL patients. Notably, 3G TKIs not only demonstrated strong inhibition against the T315I mutation, as previously reported, but also displayed superior effectiveness against certain ABL1 KD unreported mutations, such as R516L, K262T, and F401V. Similar trends were observed in CML-BP, although statistical significance was not reached likely due to the limited number of patients. Conclusion Overall, our findings indicate the prevalence and impact of ABL1 KD mutations in Ph+ ALL and CML-BP patients, highlighting the necessity for effective therapies targeting these mutations. The promising outcomes observed with 3G TKIs suggest their potential as a treatment option for both newly diagnosed and relapsed Ph+ ALL patients, offering advantages in terms of molecular response depth, rapid remission, and reduced relapse risk. Further investigations are warranted to explore the clinical significance of unreported ABL1 KD mutations and validate the effectiveness of 3G TKIs against them.

How Much Have Post-Transplant Outcomes Improved Since 2000 for Patients with Philadelphia-Positive Acute Lymphoblastic Leukemia in First Remission? a Study from the EBMT Acute Leukemia Working Party

Background Allogeneic hematopoietic cell transplantation (allo-HCT) remains an important curative modality for patients with Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) in first complete remission (CR1). Recent years have witnessed an improvement in transplant techniques and increased use of post-transplant pharmacological interventions aimed at reducing the risk of relapse. However, recent results using the combination of blinatumomab and second or third-generation tyrosine kinase inhibitors (TKI) have challenged the role of allo-HCT in CR1. To address these challenges, we assessed real-world changes over time in transplant characteristics and post-transplant outcomes in adult patients with Ph+ ALL in CR1, using a large dataset from the European Society for Blood and Marrow Transplantation (EBMT) registry. Methods We identified 3292 adult patients (45% female; median age 45 years, range 18-76) with Ph+ ALL allografted between 2001 and 2020 in CR1 from a matched sibling (38%), unrelated (54%) or haploidentical donor (8%).At transplant, 41% of patients were measurable disease (MRD) positive (pos). The comorbidity index (CI) was zero in 63% of patients with available data. Conditioning was myeloablative (MAC) in 77% of patients, and included total body irradiation (TBI) in 64% of patients. In vivo T cell depletion (TCD) and peripheral blood stem cells (PBSC) were given to 52% and 86% of patients, respectively. Most patients (66%) and donors (55%) were cytomegalovirus (CMV) positive. Median follow-up for live patients was 56 months (interquartile range [IQR] 28-32). Results We compared changes in patient and transplant characteristics over time in 245 patients transplanted in 2001-2005, 679 patients transplanted in 2006-2010, 1035 patients transplanted in 2011-2015, and 1333 patients transplanted in 2016-2020. Patients transplanted in recent years were older, were less likely to be MRDpos, and more likely to receive PBSC and TCD. The 3-year cumulative incidence of relapse (CIR) gradually and significantly decreased from 41% to 32%, 27%, and 19% over the 4 time periods (p=0.001), and non-relapse mortality (NRM) significantly decreased as well from 25% to 24%, 23% and 17% (p=0.001). The 3-year leukemia-free survival (LFS) and overall survival (OS) gradually and significantly improved over time from 34% to 44%, 50%, and 64% (p=0.001) and from 47% to 56%, 65%, and 75% (p=0.001), respectively. Finally, graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS) improved from 26% to 34%, 37%, and 49% (p=0.001). In a Cox regression multivariate analysis (MVA), a progressive and significant improvement in all transplant outcomes was noted including reduced acute and chronic GVHD, reduced CIR and NRM, and increased LFS, OS, and GRFS. LFS was also negatively affected by older age, male gender of both patients and donors, MRDpos pretransplant, and the use of reduced intensity conditioning while positively affected by the use of TBI. OS was also positively affected by younger age, female gender of patients, matched sibling donor, TBI, and TCD. This improvement in post-transplant outcomes over time was observed both in MRDpos but also in MRD negative (neg) patients. In MRDneg patients, 3-year CIR decreased from 34% to 30%, 24%, and 17% (p=0.001) over the 4 time periods whereas LFS improved from 41% to 46%, 52%, and 66% (p=0.001). Similarly, in MRD-positive patients, CIR decreased from 48% to 34%, 32%, and 23% (p=0.001) over the 4 time periods whereas LFS improved from 27% to 42%, 47% and 60% (p=0.001). Conclusion In patients with Ph+ ALL, we observed an impressive improvement over time in post-transplant outcomes with decreased CIR and NRM and improved LFS, OS, and GRFS, both in MRDpos and MRDneg patients. These large-scale, real-world data can serve as a benchmark for future studies in this setting, including those testing the combination of TKI and blinatumomab as an alternative to transplant.