Administration Of Tyrosine Kinase Inhibitors Research Articles

Clinical evaluation of neoadjuvant tyrosine kinase inhibitor administration for mast cell tumours in eight dogs

AbstractComplete surgical removal of tumour cells is the first‐line treatment for canine cutaneous mast cell tumours. Surgical removal of mast cell tumours sometimes requires radical surgery. This may cause severe complications, loss of biological function or poor cosmetic outcomes. This report describes the clinical outcomes of preoperative administration of an effective tyrosine kinase inhibitor for mast cell tumours. Five of eight cases responded to tyrosine kinase inhibitors; complete removal was possible in three cases with narrower (<1 cm) surgical margins than the conventional tumour margin estimated from the original tumour size. Mast cell tumours may not require wide resection if they are responsive to tyrosine kinase inhibitors before surgical removal. Preoperative administration of tyrosine kinase inhibitors could be a treatment option for dogs that have difficulty with complete removal causing severe surgical complications, or for owners who do not accept loss of biological function or poor cosmetic outcomes.

Efficacy of CLAE Chemotherapy Regimen Followed by Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Relapsed/Refractory Acute Leukemia

To observe the efficacy and safety of CLAE intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with relapsed/refractory acute leukemia (R/R AL). CLAE regimen [cladribine 5 mg/(m2·d), d 1-5; cytarabine 1.5 g/(m2·d), d 1-5; etoposide 100 mg/(m2·d), d 3-5] followed by allo-HSCT was used to treat 3 R/R AL patients. The patients received CLAE chemotherapy in relapsed or refractory status and underwent bone marrow puncture to judge myelodysplastic state. After an interval of 3 to 5 days, followed by preconditioning regimen for allo-HSCT [fludarabine 30 mg/(m2·d), d -7 to d -3; busulfan 0.8 mg/kg q6h, d -6 to d -3 or d -5 to d -2. If the bone marrow hyperplasia was not active and the blasts were less than 10%, busulfan should be used for 3 days. If the bone marrow hyperplasia was active and the blasts were more than 10%, busulfan should be used for 4 days]. Cyclosporin A, mycophenolate mofetil and short-term methotrexate were used for graft-versus-host disease (GVHD) prevention. After transplantation, the status of minimal residual disease (MRD) and bone marrow chimerism were regularly monitored in all 3 patients, and demethylation drugs or dasatinib were used to prevent recurrence 3 months after transplantation. 2 patients with t(11;19) translocation and relapse/refractory acute myeloid leukemia recurred within 6 months after induction of remission, and received intensive chemotherapy with CLAE regimen followed by haploidentical allo-HSCT and unrelated donor allo-HSCT, respectively. The two patients both relapsed 6 months after transplantation, then achieved complete remission by donor lymphocyte infusion, interferon, interleukin-2 and other methods, and disease-free survival was 2 years after transplantation. The other patient was chronic myelogenous leukemia who developed acute lymphoblastic leukemia during oral administration of tyrosine kinase inhibitor, accompanied by T315I and E255K mutations in ABL1 kinase region and additional chromosomal abnormalities. After morphological remission by induction chemotherapy, central nervous system leukemia was complicated. Intensive chemotherapy with CLAE regimen followed by sibling allo-HSCT was performed in the positive state of MRD. The patient relapsed 3 months after transplantation, and achieved remission after chimeric antigen receptor T-cell (CAR-T) therapy, however, he died 5 months after transplantation because of severe cytokine release syndrome (CRS) and GVHD. CLAE regimen followed by allo-HSCT may be an effective salvage treatment option for R/R AL patients to prolong the overall survival.

Portal hemodynamic effects of different TKIs in patients with advanced hepatocellular carcinoma: A prospective cohort study.

e15126 Background: Tyrosine kinase inhibitors (TKIs) are considered to have effects on portal collateral circulation with portal hypertension. According to previous small sample clinical reports, short-term administration of sorafenib might have an effect of decreasing portal venous pressure, while lenvatinib aggravated portal hypertension. Long-term effects of TKIs on portal pressure are still unclear. Therefore, We conducted a prospective cohort study to explore the efficacy of different TKIs for portal circulation in patients with advanced hepatocellular carcinoma. Methods: 27 Child-Pugh class A or B patients with advanced HCC were enrolled in this study, 13 patients received lenvatinib, 7 patients sorafenib, and 7 patients regorafenib. Changes of portal hemodynamic parameters were measured by duplex Doppler ultrasonography, including portal venous area (PVA), portal venous flow velocity (PVV) and congestion index (CI) before and after administration of TKIs for an average 40-50 days. Results: In both regorafenib and sorafenib cohorts, PVA decreased after treatment, although the difference was not significant. PVF significantly reduced in sorafenib cohort (24.96±5.60 vs. 15.46±4.50, P= 0.014) and regorafenib cohort (21.43±2.09 vs. 16.01±1.28, P= 0.024), therefore CI significantly increased in sorafenib cohort (0.060±0.042 vs. 0.088±0.040, P= 0.046) and regorafenib cohort (0.068±0.032 vs. 0.090±0.030, P= 0.043). In lenvatinib, both PVA and PVF have no significant change, while CI increased significantly (0.057±0.027 vs. 0.074±0.040, P= 0.030). Conclusions: In this study, TKIs showed different effects on portal hemodynamic change in advanced HCC. Large sample and long time follow-up research will be necessary to verify their clinical and mechanism effects. [Table: see text]

Comparative biochemical kinase activity analysis identifies rivoceranib as a highly selective VEGFR2 inhibitor

Vascular endothelial growth factor receptor 2 (VEGFR2), a key regulator of tumor angiogenesis, is highly expressed across numerous tumor types and has been an attractive target for anti-cancer therapy. However, clinical application of available VEGFR2 inhibitors has been challenged by limited efficacy and a wide range of side effects, potentially due to inadequate selectivity for VEGFR2. Thus, development of potent VEGFR2 inhibitors with improved selectivity is needed. Rivoceranib is an orally administered tyrosine kinase inhibitor that potently and selectively targets VEGFR2. A comparative understanding of the potency and selectivity of rivoceranib and approved inhibitors of VEGFR2 is valuable to inform rationale for therapy selection in the clinic. Here, we performed biochemical analyses of the kinase activity of VEGFR2 and of a panel of 270 kinases to compare rivoceranib to 10 FDA-approved kinase inhibitors (“reference inhibitors”) with known activity against VEGFR2. Rivoceranib demonstrated potency within the range of the reference inhibitors, with a VEGFR2 kinase inhibition IC50 value of 16 nM. However, analysis of residual kinase activity of the panel of 270 kinases showed that rivoceranib displayed greater selectivity for VEGFR2 compared with the reference inhibitors. Differences in selectivity among compounds within the observed range of potency of VEGFR2 kinase inhibition are clinically relevant, as toxicities associated with available VEGFR2 inhibitors are thought to be partly due to their effects against kinases other than VEGFR2. Together, this comparative biochemical analysis highlights the potential for rivoceranib to address clinical limitations associated with off-target effects of currently available VEGFR2 inhibitors.

Inclusion body myositis triggerred with long-term imatinib use.

Imatinib is an orally administered tyrosine kinase inhibitor with wide clinical use in different indications from solid tumors to hematologic malignancies. Inclusion body myositis (IBM) is an acquired myopathy of both inflammatory and degenerative nature. We present an 81 years old male with a history of gastrointestinal stromal tumor (GIST) operated 8 years ago and was evaluated for the progressive loss of weight and muscle strength leading to total immobilization in 6 months. He was under imatinib for 8 years despite the remission of GIST. Physical examination disclosed diffuse loss of muscle strength, most prominently involvement of distal upper and proximal lower extremity in an asymmetrical pattern with normal serum creatinine kinase level (CK). Further investigations including bilateral thigh MRI, electromyography (EMG), and PET/CT suggested myositis and degenerative myopathy and ruled out any malignancy. Quadriceps femoris biopsy proved the diagnosis of IBM and no trigger except for imatinib was displayed. Clinical improvement in terms of weight loss and muscle weakness was achieved after the discontinuation of imatinib. This is the first case of IBM associated with prolonged use of imatinib not reported in the literature so far. Since imatinib is widely used in different conditions, it is important to be aware of even its rare adverse effects. Poor response of IBM to conventional immunosuppressive agents enhances the value of etiology identification to relieve symptoms in addition to supportive care.

Long-term response to pimitespib in postoperative recurrent gastrointestinal stromal tumors with PDGFRA D842V mutation: a case report

BackgroundExon 18 D842V, which is a point mutation from aspartic acid to valine at codon 842, is the most frequent mutation in Platelet-Derived Growth Factor Receptor alpha (PDGFRA)-mutated gastrointestinal stromal tumor (GIST). In the Japanese GIST guidelines, no standard systematic therapy is available for this type of GIST, which is refractory after recurrence. Recently, pimitespib (PIMI), a novel heat shock protein 90 (HSP90) inhibitor, was approved for the treatment of advanced GIST in a phase III study. This report presents a case of a long-term response to PIMI in GIST with PDGFRA D842V mutation.Case presentationA 55-year-old woman was diagnosed with primary GIST of the stomach and underwent partial gastrectomy. Eight years after the operation, recurrent GISTs were identified as multiple recurrent peritoneal GISTs in the upper right abdomen and pelvic cavity. We administered tyrosine kinase inhibitors, but they achieved poor effects. After failure of the standard treatment, PIMI was administered and achieved a partial response in the patient. The highest reduction rate was 32.7%. After PIMI failed, we performed multiplex gene panel testing, which revealed the PDGFRA D842V mutation.ConclusionsWe report the first case of long-term response to PIMI in PDGFRA D842V mutant GIST. Pimitespib may be effective for treating GIST harboring this mutation by inhibiting HSP90.

Analysis of intracellular tyrosine phosphorylation in circulating neutrophils as a rapid assay for the in vivo effect of oral tyrosine kinase inhibitors.

Tyrosine kinases are crucial signaling components of diverse biological processes and are major therapeutic targets in various malignancies and immune-mediated disorders. A critical step of development of novel tyrosine kinase inhibitors is the transition from the confirmation of the in vitro effects of drug candidates to the analysis of their in vivo efficacy. To facilitate this transition, we have developed a rapid in vivo assay for the analysis of the effect of oral tyrosine kinase inhibitors on basal tyrosine phosphorylation of circulating mouse neutrophils. The assay uses a single drop of peripheral blood without sacrificing the mice. Flow cytometry using intracellular staining by fluorescently labeled anti-phosphotyrosine antibodies revealed robust basal tyrosine phosphorylation in resting circulating neutrophils. This signal was abrogated by the use of isotype control antibodies or by pre-saturation of the anti-phosphotyrosine antibodies with soluble phosphotyrosine amino acids or tyrosine-phosphorylated peptides. Basal tyrosine phosphorylation was dramatically reduced in neutrophils of triple knockout mice lacking the Src-family tyrosine kinases Hck, Fgr, and Lyn. Neutrophil tyrosine phosphorylation was also abrogated by oral administration of the Abl/Src-family inhibitor dasatinib, a clinically used anti-leukemic agent. Detailed dose-response and kinetic studies revealed half-maximal reduction of neutrophil tyrosine phosphorylation by 2.9mg/kg dasatinib, with maximal reduction observed 2h after inhibitor administration. Taken together, our assay allows highly efficient analysis of the in vivo effect of orally administered tyrosine kinase inhibitors, and may be used as a suitable alternative to other existing approaches.

Molecular patterns of egyptian patients with non-squamous non-small-cell lung cancers: a clinicopathological study

BackgroundDriver molecular aberrations, such as epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) gene rearrangement, play an important role in the oncogenesis and progression of non-squamous non-small-cell lung cancers (NSCLC). Therefore, this study aimed to detect the incidence of driver mutations among non-squamous NSCLC.Patients and methodsThis was a retrospective-prospective cohort study on 131 patients with non-squamous NSCLC. Data on age, smoking status, chest symptoms, method of lung cancer diagnosis, molecular testing, including EGFR mutations in formalin-fixed paraffin-embedded (FFPE) tumor tissue and serum circulating tumor DNA using next-generation sequencing and ALK gene rearrangement by FFPE tumor tissue, and follow-up data regarding treatment modalities and outcomes were collected.ResultsThe median age of the patients was 57 years (range: 32–79 years). Out of 131 patients, 97 were males (74%), and 90 (68.7%) were smokers. Among 128 patients tested, 16 (12.5%) had EGFR mutations detected with either technique by formalin-fixed paraffin-embedded (FFPE) tumor tissue or/and serum circulating tumor DNA using next-generation sequencing, and 6 (4.7%) had ALK rearrangement by FFPE tumor tissue. The majority (62.6%) presented with metastatic disease. Among the 102 patients who received first-line systemic therapy, the objective response rate was 50.0% in mutated NSCLC versus 14.6% in non-mutated (p < 0.001). Among the eight mutated patients who received first-line tyrosine kinase inhibitors (TKIs), 7 patients achieved either complete response or partial response. Among the 22 mutated patients, the median overall survival was 3 months in those who did not receive targeted therapy versus not reached in those who received any type of targeted therapy (p < 0.001).ConclusionScreening patients with newly diagnosed non-squamous NSCLC for driver mutations is essential for major prognostic and therapeutic implications. Early administration of TKIs in mutated patients significantly improves disease outcomes.

The effects of low-dose sorafenib on epithelial-mesenchymal transition and multidrug resistance markers in HepG2 cell line

Objectives: Sorafenib is an orally administered tyrosine kinase inhibitor in hepatocellular cancer. Low sorafenib concentrations are attained during pharmacotherapy due to pharmacokinetic profile and patient inadherence. Resistance to treatment is a limitation to improving survival. Underlying mechanisms include epithelial-mesenchymal transition. The aim of the study was to evaluate epithelial-mesenchymal transition and multidrug resistance-related parameters in HepG2 cells following low-dose and short-term sorafenib treatment. Methods: Epithelial-mesenchymal transition and multidrug resistance-related markers were examined by quantitative PCR, flow cytometry, and confocal laser scanning microscopy. Results: An increase in epithelial marker E-cadherin and downregulation of mesenchymal markers Vimentin and Snail1 were detected by gene expression analysis. While P-glycoprotein expression increased, multidrug resistance protein 1, and breast cancer resistance protein mRNA levels did not alter after sorafenib treatment. The accumulation of the ABC transporter substrate rhodamine 123 in the cells increased following the treatment, corresponding to a less efficient efflux of rhodamine 123 and a possible effect on other transporters and mechanisms. Conclusions: The results indicate a protective effect of sorafenib against epithelial-mesenchymal transition and upregulation in P-glycoprotein expression, which is, however, not sufficient to cause less intracellular rhodamine 123 accumulation. The effects of low-dose and short-term sorafenib on epithelial-mesenchymal transition and multidrug resistance-related markers might contribute to enlightening new treatment strategies in hepatocellular cancer.

Paired Comparison of Routine Molecular Screening of Patient Samples with Advanced Non-Small Cell Lung Cancer in Circulating Cell-Free DNA Using Three Targeted Assays.

Progressive advanced non-small cell lung cancer (NSCLC) accounts for about 80-85% of all lung cancers. Approximately 10-50% of patients with NSCLC harbor targetable activating mutations, such as in-frame deletions in Exon 19 (Ex19del) of EGFR. Currently, for patients with advanced NSCLC, testing for sensitizing mutations in EGFR is mandatory prior to the administration of tyrosine kinase inhibitors. Plasma was collected from patients with NSCLC. We carried out targeted NGS using the Plasma-SeqSensei™ SOLID CANCER IVD kit on cfDNA (circulating free DNA). Clinical concordance for plasma detection of known oncogenic drivers was reported. In a subset of cases, validation was carried out using an orthogonal OncoBEAMTM EGFR V2 assay, as well as with our custom validated NGS assay. Somatic alterations were filtered, removing somatic mutations attributable to clonal hematopoiesis for our custom validated NGS assay. In the plasma samples, driver targetable mutations were studied, with a mutant allele frequency (MAF) ranging from 0.00% (negative detection) to 82.25%, using the targeted next-generation sequencing Plasma-SeqSensei™ SOLID CANCER IVD Kit. In comparison with the OncoBEAMTM EGFR V2 kit, the EGFR concordance is 89.16% (based on the common genomic regions). The sensitivity and specificity rates based on the genomic regions (EGFR exons 18, 19, 20, and 21) were 84.62% and 94.67%. Furthermore, the observed clinical genomic discordances were present in 25% of the samples: 5% in those linked to the lower of coverage of the OncoBEAMTM EGFR V2 kit, 7% in those induced by the sensitivity limit on the EGFR with the Plasma-SeqSensei™ SOLID CANCER IVD Kit, and 13% in the samples linked to the larger KRAS, PIK3CA, BRAF coverage of the Plasma-SeqSensei™ SOLID CANCER IVD kit. Most of these somatic alterations were cross validated in our orthogonal custom validated NGS assay, used in the routine management of patients. The concordance is 82.19% in the common genomic regions (EGFR exons 18, 19, 20, 21; KRAS exons 2, 3, 4; BRAF exons 11, 15; and PIK3CA exons 10, 21). The sensitivity and specificity rates were 89.38% and 76.12%, respectively. The 32% of genomic discordances were composed of 5% caused by the limit of coverage of the Plasma-SeqSensei™ SOLID CANCER IVD kit, 11% induced by the sensitivity limit of our custom validated NGS assay, and 16% linked to the additional oncodriver analysis, which is only covered by our custom validated NGS assay. The Plasma-SeqSensei™ SOLID CANCER IVD kit resulted in de novo detection of targetable oncogenic drivers and resistance alterations, with a high sensitivity and accuracy for low and high cfDNA inputs. Thus, this assay is a sensitive, robust, and accurate test.

Masitinib for mild-to-moderate Alzheimer’s disease: results from a randomized, placebo-controlled, phase 3, clinical trial

BackgroundMasitinib is an orally administered tyrosine kinase inhibitor that targets activated cells of the neuroimmune system (mast cells and microglia). Study AB09004 evaluated masitinib as an adjunct to cholinesterase inhibitor and/or memantine in patients with mild-to-moderate dementia due to probable Alzheimer’s disease (AD).MethodsStudy AB09004 was a randomized, double-blind, two parallel-group (four-arm), placebo-controlled trial. Patients aged ≥50 years, with clinical diagnosis of mild-to-moderate probable AD and a Mini-Mental State Examination (MMSE) score of 12–25 were randomized (1:1) to receive masitinib 4.5 mg/kg/day (administered orally as two intakes) or placebo. A second, independent parallel group (distinct for statistical analysis and control arm), randomized patients (2:1) to masitinib at an initial dose of 4.5 mg/kg/day for 12 weeks that was then titrated to 6.0 mg/kg/day, or equivalent placebo. Multiple primary outcomes (each tested at a significance level of 2.5%) were least-squares mean change from baseline to week 24 in the Alzheimer’s Disease Assessment Scale - cognitive subscale (ADAS-cog), or the Alzheimer’s Disease Cooperative Study Activities of Daily Living Inventory scale (ADCS-ADL). Safety for each masitinib dose level was compared against a pooled placebo population.ResultsMasitinib (4.5 mg/kg/day) (n=182) showed significant benefit over placebo (n=176) according to the primary endpoint of ADAS-cog, −1.46 (95% CI [−2.46, −0.45]) (representing an overall improvement in cognition) versus 0.69 (95% CI [−0.36, 1.75]) (representing increased cognitive deterioration), respectively, with a significant between-group difference of −2.15 (97.5% CI [−3.48, −0.81]); p<0.001. For the ADCS-ADL primary endpoint, the between-group difference was 1.82 (97.5% CI [−0.15, 3.79]); p=0.038 (i.e., 1.01 (95% CI [−0.48, 2.50]) (representing an overall functional improvement) versus −0.81 (95% CI [−2.36, 0.74]) (representing increased functional deterioration), respectively). Safety was consistent with masitinib’s known profile (maculo-papular rash, neutropenia, hypoalbuminemia). Efficacy results from the independent parallel group of titrated masitinib 6.0 mg/kg/day versus placebo (n=186 and 91 patients, respectively) were inconclusive and no new safety signal was observed.ConclusionsMasitinib (4.5 mg/kg/day) may benefit people with mild-to-moderate AD. A confirmatory study has been initiated to substantiate these data.Trial registrationEudraCT: 2010-021218-50. ClinicalTrials.gov: NCT01872598

A phase II study to evaluate anlotinib plus TQB2450 as adjuvant therapy in patients with esophageal squamous cell carcinoma (ALTER-E005).

TPS488 Background: About 30.3-58.0% of patients who undergo esophagectomy may experience recurrence. The efficacy of postoperative chemoradiation has not been demonstrated in a randomized trial in patients with esophageal squamous cell carcinoma (ESCC) compared to surgery along. Therefore, it is urgent to explore more effective and safer postoperative regimen for resectable ESCC. Checkmate 577 has demonstrated immunotherapy can prolong disease free survival (DFS) for patients who have residual disease following preoperative chemoradiation and R0 resection. Anlotinib is an orally administered tyrosine kinase inhibitor that targets VEGFR1-3, FGFR1-4 and PDGFRα/β. In a randomized, double-blind phase 2 trial, the use of anlotinib in previously treated metastatic ESCC patients significantly improved progression-free survival (PFS) compared with placebo ( NCT02649361 ). TQB2450 is a novel humanized monoclonal antibody against PD-L1, which has shown encouraging activity in combination with anlotinib in the treatment of multiple tumors, such as biliary tract cancer (NCT03996408) and ovarian cancer (NCT04236362). The ALTER-E005 study is designed to evaluate the efficacy and safety of anlotinib combined with TQB2450as adjuvant therapy in ESCC patients. Methods: ALTER-E005 is a multi-center, single-arm, phase II study. A total of 30 patients will be enrolled. Eligible pts (≥18 years) must be histologically confirmed T1-2N1-3M0 or T3-4NanyM0 ESCC; received radical (R0) resection of ESCC with no recurrence in imaging examination within 6-12 weeks after surgery; ECOG PS 0–1. Patients enrolled will receive oral anlotinib 12 mg on days 1-14 and intravenous TQB2450 1,200 mg on day 1 every 3 weeks until disease recurrence. The primary endpoint is DFS. The secondary endpoints include safety, 1-year DFS rate, 3-year DFS rate, 1-year overall survival (OS) rate, and 3-year OS rate. Enrollment to the ALTER-E005 trial is currently ongoing in China. Clinical trial information: NCT05252078 .

Twenty years of evolution of CML therapy: how the treatment goal is moving from disease to patient.

The introduction of imatinib in 2000 opened the era of tyrosine kinase inhibitors (TKIs) for CML therapy and has revolutionized the life expectancy of CML patients, which is now quite like the one of the healthy aged population. Over the last 20 years, both the TKI therapy itself and the objectives have undergone evolutions highlighted and discussed in this review. The main objective of the CML therapy in the first 10 years after TKI introduction was to abolish the disease progression from the chronic to the blastic phase and guarantee the long-term survival of the great majority of patients. In the second 10 years (from 2010 to the present), the main objective of CML therapy moved from survival, considered achieved as a goal, to treatment-free remission (TFR). Two phenomena emerged: no more than 50-60% of CML patients could be candidates for discontinuation and over 50% of them molecularly relapse. The increased cumulative incidence of specific TKI off-target side effects was such relevant to compel to discontinue or reduce the TKI administration in a significant proportion of patients and to avoid a specific TKI in particular settings of patients. Therefore, the treatment strategy must be adapted to each category of patients. What about the patients who do not get or fail the TFR? Should they be compelled to continue the TKIs at the maximum tolerated dose? Alternative strategies based on the principle of minimal effective dose have been tested with success and they are now re-evaluated with more attention, since they guarantee survival and probably a better quality of life, too. Moving from treating the disease to treating the patient is an important change of paradigm. We can say that we are entering a personalized CML therapy, which considers the patients' age, their comorbidities, tolerability, and specific objectives. In this scenario, the new techniques supporting the monitoring of the patients, such as the digital PCR, must be considered. In the present review, we present in deep this evolution and comment on the future perspectives of CML therapy.

Efficacy and safety of anlotinib as an adjuvant therapy in hepatocellular carcinoma patients with a high risk of postoperative recurrence.

Hepatocellular carcinoma (HCC) has a high rate of postoperative recurrence and lacks an effective treatment to prevent recurrence. This study aims to investigate the efficacy and safety of anlotinib in postoperative adjuvant therapy for HCC patients with high-risk recurrence factors. For this multicenter, retrospective study, we recruited 63 HCC patients who received either anlotinib (n=27) or transcatheter arterial chemoembolization (TACE) (n=36) from six research centers in China between March 2019 and October 2020. The primary endpoint was disease-free survival (DFS) and the secondary endpoints were overall survival (OS) and safety. In this study, the median follow-up time was 25.9 and 26.8 months in the anlotinib and TACE groups, respectively. There was no significant difference in the median DFS between the anlotinib [26.8 months, 95% confidence interval (95% CI): 6.8-NE] and TACE groups (20.6 months, 95% CI: 8.4-NE). The 12-month OS rates in the anlotinib and TACE groups were 96.3% and 97.2%, respectively. In the anlotinib group, 19 of 27 patients (70.4%) experienced treatment-emergent adverse events, with the most common events (≥10%) being hypertension (22.2%) and decreased platelet count (22.2%). The results indicate that anlotinib, as a new, orally administered tyrosine kinase inhibitor, has the same efficacy as TACE, and side effects can be well controlled.

De-escalation or discontinuation of tyrosine kinase inhibitor in patients with chronic myeloid leukemia: A multicentral, open-label, prospective trial in China.

Background: Long-term treatment-free remission (TFR) represents a new goal for chronic myeloid leukemia (CML). Optimizing dose of tyrosine kinase inhibitors (TKIs) in the CML treatment maybe a new challenge to maintain effective and improving patients' quality of life. We hypothesized that administration of low-dose TKIs does not compromise major molecular response (MMR) in patients with CML who have a deep molecular response (DMR). Methods: We did an open-label, randomized trial at eight hospitals in China. Eligible CML-CP patients (aged 18-70 years) had shown continuous response to TKI more than 5 years and maintained MR4.5 (BCR-ABLIS ≤ 0.0032%) in recent 18 months. Patients were randomly assigned (1:1) to the TKI de-escalation group or the discontinuation group. Randomization was done with permuted blocks (block size four) and implemented through an interactive web-based randomization system. Recurrence was defined as the single sample with real time Quantitative PCR (RT-qPCR) measurement greater than 0.1% (MMR). The primary endpoint was 12-month MMR rate in patients who received de-escalation or discontinuation of TKIs. This study was registered at ClinicalTrials.gov (NCT04143087). Results: Around 125 patients were enrolled between October 23, 2019 and October 31, 2020, 62 patients received dose de-escalation of TKIs, while 63 patients in the discontinuation group. In the de-escalation group, molecular recurrence-free survival at 12 months was 88.32% (95% CI 79%-98%), whereas molecular recurrence-free survival in the discontinuation group at 12 months was 59.98% (95% CI 47-73). No progressions occurred at the data cut-off date. All 29 recurrence cases restart TKI treatment returned to MMR. Cytolytic NK cells as a proportion of lymphocyte cells were significantly increased from baseline after 6 months whether in the de-escalation or TKIs cessation group (P=0.048, 0.001, respectively); compared with the relapsing patients, Tregs proportion was decreased (P=0.003), and higher proportion of NK cells were found in non-relapsing patients whetherin TKI de-escalation or discontinuation group (P=0.011, 0.007, respectively). We also found that the de-escalation group showed better disease-specific HRQOL in regards to its impact on emotional functioning, fatigue, pain, and financial difficulties. Conclusion: With 88.32% MMR in 12-months follow-up after de-escalation TKIs' treatment, dose-halving could become a new treatment paradigm for CML patients who with DMR under continuing maintenance therapy with TKIs.

Mechanisms of resistance to tyrosine kinase inhibitors in liver cancer stem cells and potential therapeutic approaches.

The administration of tyrosine kinase inhibitors (TKIs) for the treatment of advanced-stage patients is common in hepatocellular carcinoma (HCC). However, therapy resistance is often encountered, and its emergence eventually curtails long-term clinical benefits. Cancer stem cells (CSCs) are essential drivers of tumor recurrence and therapy resistance; thus, the elucidation of key hallmarks of resistance mechanisms of liver CSC-driven HCC may help improve patient outcomes and reduce relapse. The present review provides a comprehensive summary of the intrinsic and extrinsic mechanisms of TKI resistance in liver CSCs, which mediate treatment failure, and discusses potential strategies to overcome TKI resistance from a preclinical perspective.

Tyrosine Kinase Inhibition Alters Intratumoral CD8+ T-cell Subtype Composition and Activity.

Targeted therapy with a tyrosine kinase inhibitor (TKI) such as imatinib is effective in treating gastrointestinal stromal tumor (GIST), but it is rarely curative. Despite the presence of a robust immune CD8+ T-cell infiltrate, combining a TKI with immune-checkpoint blockade (ICB) in advanced GIST has achieved only modest effects. To identify limitations imposed by imatinib on the antitumor immune response, we performed bulk RNA sequencing (RNA-seq), single-cell RNA-seq, and flow cytometry to phenotype CD8+ T-cell subsets in a genetically engineered mouse model of GIST. Imatinib reduced the frequency of effector CD8+ T cells and increased the frequency of naïve CD8+ T cells within mouse GIST, which coincided with altered tumor chemokine production, CD8+ T-cell recruitment, and reduced CD8+ T-cell intracellular PI3K signaling. Imatinib also failed to induce intratumoral T-cell receptor (TCR) clonal expansion. Consistent with these findings, human GISTs sensitive to imatinib harbored fewer effector CD8+ T cells but more naïve CD8+ T cells. Combining an IL15 superagonist (IL15SA) with imatinib restored intratumoral effector CD8+ T-cell function and CD8+ T-cell intracellular PI3K signaling, resulting in greater tumor destruction. Combination therapy with IL15SA and ICB resulted in the greatest tumor killing and maintained an effector CD8+ T-cell population in the presence of imatinib. Our findings highlight the impact of oncogene inhibition on intratumoral CD8+ T cells and support the use of agonistic T-cell therapy during TKI and/or ICB administration.

Chronic Myeloid Leukemia (CML) at National Referral Hospital in Indonesia

Chronic Myeloid Leukemia (CML) is a myeloproliferative neoplasm characterized by the presence of the Philadelphia chromosome and BCR-ABL fusion oncogene. CML is one of the illnesses that may be treated using Tyrosine Kinase Inhibitors (TKIs), a type of targeted therapy. Since TKIs are the standard of therapy, long-term survival of CML has improved compared to chemotherapy and interferon-alpha. For the first-line treatment for CML, there are four commercially available TKIs that serve as an integral part of the disease management. However, there are many challenges in diagnosing, treating, and monitoring patients with chronic phase CML in Indonesia. This study highlights the epidemiology data of chronic phase CML patients, particularly at Dr. Cipto Mangunkusumo General Hospital, an Indonesian national referral hospital, and how to diagnose, select first-line TKIs, and monitor the response of treatment after TKIs administration.

P606: META-ANALYSIS OF LOW ALLELIC BURDEN C481 BTK-MUTATIONS CALLS FOR CAUTION IN IBRUTINIB RESISTANCE EVALUATION

Background: Introduction of the orally administered tyrosine kinase inhibitor ibrutinib, a drug approved for relapsed or refractory mantle cell lymphoma in late 2013 and chronic lymphocytic leukemia in 2014, has changed treatment algoritms for B-cell malignancies and improved progression-free survival. Ibrutinib irreversibly targets Bruton’s tyrosine kinase (BTK), thus interrupting B-cell receptor signaling. However, it is known that mutations in the BTK gene, located on the X chromosome, can mediate acquired resistance, specifically modifying cysteine residue 481 to serine (C481S, X:101356176, GRCh38). Aims: Despite this knowledge, it is still unknown how low mutational burden can contribute to general resistance towards ibrutinib treatment. Thus, we performed a meta-analysis based on previous cardinal studies to investigate the collective and gender-specific distribution of variant allele frequencies. Methods: We implemented meta-analysis of single-nucleotide variant calls from seven studies involving whole-exome sequencing (Woyach et al. 2014 and 2017, Maddocks et al. 2015, Ahn et al. 2017, Kanagal-Shamanna et al. 2019, Gángó et al. 2020, Bödör et al. 2021) on mutational profiling concerning ibrutinib resistance and CLL. Four of these studies contained gender specific data. Computational analyses, statistics, and visualization were performed in Wolfram Language, R, and GraphPad Prism. Results: From the available data included in these studies, we were able to base our analyses on 226 non-BTK mutations and 170 BTK mutations within a variant allele frequency (VAF) range of 0.0001–0.9, of which 93 mutation candidates from males (VAF < 0.9) and 77 from females (VAF < 0.44) were observed. Extrapolative analysis of allele frequency distribution from all other variants (excl. BTK) in the studies revealed an exponential increase in the number of low burden variants below 10% VAF (R2>0.99). These variants were not significantly different between genders (PMann-Whitney=0.24, nmale=130, nfemale=73). In contrast, a significant difference was observed between male variant allele frequencies (PMann-Whitney=0.005) and females owing to BTK hemizygosity in males. However, this significance persisted when female BTK mutations were transformed to reflect a single copy (VAF/2, PMann-Whitney=0.015, ΔVAF=0.05) for gender comparison and even when observations for males were alternatively transformed to reflect two copies (2*VAF, PMann-Whitney<0.001, ΔVAF=0.19). The previously discovered threshold of 10% was set as the detection limit. Summary/Conclusion: Defining specific molecular contributions in drug resistance is imperative for the correct use of targeted therapy. It has been questioned how the low allelic burden of BTK mutations plays a role. Therefore, it is crucial to investigate the lower limit of detection. The meta-analysis suggests that variants below a certain threshold, here empirically 10%, may in many cases be false-positive variants, in agreement with other reports involving WES in general, introduced by erroneous base calling, PCR errors, etc. Although intriguing, it remains to elaborate whether the haploinsufficiency of BTK in males skew in the degree of ibrutinib resistance.

A New Paradigm of Cardio-Hematological Monitoring in Chronic Myeloid Leukemia Patients Treated With Tyrosine Kinase Inhibitors.

Significant progress has been achieved in treating patients with onco-hematological diseases, including chronic myeloid leukemia (CML). This is primarily associated with the development of targeted therapy involving tyrosine kinase inhibitors (TKIs), such as imatinib, nilotinib, bosutinib, dasatinib, and ponatinib. Along with the increased survival of patients with CML, special attention has recently been paid to cardiovascular complications in CML patients due to the prevalence of cardiovascular diseases in the general population and the toxicity profile of targeted drugs.This article presents the strategy for reducing cardiovascular risk in CML patients treated with TKIs. We discuss the components of cardiovascular risk in CML patients and the findings of current studies. Current data confirm the increased cardiovascular risk in the CML population compared to the general population, which necessitates the widespread introduction of cardiovascular prevention strategies in CML patients. The pharmacokinetics and pharmacodynamics of TKIs on the cardiovascular system are discussed. We propose two main approaches in the strategy of cardiovascular risk prevention in patients with CML, namely, before the start of TKI administration and during TKI treatment. This article presents the diagnostic assessment before prescribing TKIs, as well as while monitoring TKI therapy, and discusses the features of the choice of TKIs depending on patients’ general and cardiovascular comorbidity. Emphasis is placed on the risk stratification in patients with CML following general population algorithms, lifestyle modifications, and statin therapy for achieving the target levels of cardiovascular indicators. We also discuss unsolved questions in the current clinical guidelines and ways to further develop a cardiovascular risk-reducing strategy for CML patients.