Nilotinib for imatinib-resistant or -intolerant chronic myeloid leukemia in chronic phase,accelerated phase,or blast crisis: A single- and multiple-dose,open-label pharmacokinetic study in Chinese patients

Background: Nilotinib, an oral second-generation Bcr-Abi tyrosine kinase inhibitor, is approved in the United States and European Union for the treatment of Philadelphia chromosome-positive (Ph+), chronic-phase (CP) or accelerated-phase (AP) chronic myeloid leukemia (CML) resistant to or intolerant of prior therapy, including imatinib. Information on the pharmacokinetics of nilotinib in Chinese patients with CML is lacking, and regulatory requirements for registration of this drug are needed in China.Objectives: This study assessed the pharmacokinet-ics of single and multiple oral doses of nilotinib in Chinese patients with CML and compared the pharmacokinetic profiles of nilotinib between the Chinese patients and a subgroup of white patients with CML.Methods: Chinese patients aged ≥18 years with Ph+ CML-CP, CML-AP, or CML-BC (blast crisis) resistant to or intolerant of imatinib were eligible. Patients were administered oral nilotinib 400 mg BID for 15 days. Serial blood samples were collected before and at 1, 2, 3, 5, 8, and 12 hours after the administration of a single dose (day 1) and multiple doses (day 15, steady state). Serum nilotinib concentrations were determined using a validated liquid chromatography-tandem mass spectrometry assay, and pharmacokinetic parameters of nilotinib were calculated using a noncompartmental method. Tolerability was assessed using cardiac assessments; laboratory analysis (hematology, blood chemistry, and urinalysis); and physical examination, including vital signs.Results: Twenty-three patients were enrolled (18 men, 5 women; mean age, 40.0 years; mean weight, 68.3 kg; CML-CP, 22 patients; CML-AP, 1). All 23 patients were included in the tolerability analysis. Two patients withdrew consent and discontinued after administration of the first dose; thus, 21 patients were included in the pharmacokinetic analysis. Median T^max was ~2 hours after administration of single and multiple doses. At steady state, C_min was 1025.4 ng/mL and C_max was 2160.7 ng/mL. Mean AUCs from time 0 to the end of the dosing interval τ (AUC_0-τ) were 5076.3 and 17,751.3 ng · h/mL at days 1 and 15, respectively, representing an accumulation factor of 3.92. Apparent oral clearance (CL/F) was 0.39 L/h/kg (range, 0.12–0.74 L/h/ kg) at steady state. The study found a 42% intersubject variability in nilotinib pharmacokinetics. Steady-state C_max, C_min, AUC_0-τ, and CL/F were not significantly different from those previously reported in a subgroup of white patients with CML who received the same 400-mg BID dose. Rash (11/23 patients [47.8%]) and elevated bilirubin, headache, and muscle pain (4 patients each [17.4%]) were the most frequently reported nonhematologic adverse events.Conclusions: In this pharmacokinetic study in Chinese patients with CML resistant to or intolerant of imatinib, nilotinib 400 mg BID was rapidly absorbed after a single dose and multiple doses. The steady-state pharmacokinetic properties in this population were consistent with those reported previously in white patients with CML.     

Therapeutic drug monitoring of imatinib in chronic myeloid leukemia: experience from 1216 patients at a centralized laboratory

This study set out to examine in a large real‐life cohort of patients with chronic myeloid leukemia (CML) the impact of imatinib threshold of 1000 ng/mL on molecular response, as suggested in a small subset of patients. Patient plasma samples were submitted from around France to a central facility, free of charge under the auspices of the European Treatment and Outcome Study (EUTOS) for CML. Submitting physicians were required to complete an ‘imatinib monitoring request form’, including details of why therapeutic drug monitoring (TDM) was requested, dose and duration of imatinib treatment, cytogenetic and molecular response, adverse events, and concurrent medications. Imatinib trough plasma concentration (C_min) was measured at the central facility. Among 1985 eligible plasma samples analyzed, from 1216 CML patients, imatinib C_min correlated positively with reported imatinib dose, but interpatient variability in C_min was high (60%). A logistic regression analysis revealed that treatment duration and imatinib C_min > 1000 ng/mL were significantly associated with major and complete molecular responses with odds ratios of 1.69 and 2.08, respectively. These data support in real‐life setting that imatinib C_min threshold of 1000 ng/mL is associated with major and complete molecular response and that TDM could play an important role in dose optimization.     

Improving frontline treatment for chronic myeloid leukemia: emerging evidence for use of nilotinib and dasatinib

The approval of imatinib in 2001 changed the landscape of chronic myeloid leukemia (CML) management, becoming the standard of care and improving the survival rates of patients. With the prevalent use of imatinib worldwide, it was observed that up to one-third of patients are resistant to or intolerant of imatinib therapy, fueling the search for safer and more effective agents. The newer and more potent tyrosine kinase inhibitors nilotinib and dasatinib were first indicated for the treatment of imatinib-resistant/-intolerant patients, for whom these agents are both safe and efficacious. More recent clinical studies have examined nilotinib and dasatinib in the frontline setting in newly diagnosed patients. Data reported from the phase III ENESTnd (Evaluating Nilotinib Efficacy and Safety in Clinical Trials-Newly Diagnosed Patients) study and the DASISION (Dasatinib versus Imatinib in Patients with Newly Diagnosed Chronic-phase CML) trial support the use of nilotinib and dasatinib as potential new standards for frontline care of newly diagnosed patients with CML in chronic phase. Furthermore, both agents have received regulatory approval for use as frontline agents. These agents have demonstrated significantly superior efficacy compared with imatinib, as measured by complete cytogenetic response and major molecular response rates. In addition, progression to advanced disease was significantly lower for nilotinib, and a trend toward lower progression was observed with dasatinib. Although both nilotinib and dasatinib are generally well tolerated in the frontline setting, they have different safety profiles that may affect their selection as treatment. Understanding the efficacy, safety profiles, and patterns of resistance to various BCR-ABL1 mutations of these newer agents, as well as implementing management strategies to treat adverse events, will help physicians to provide the best therapy options for their patients with CML.     

Outcomes of adolescents and young adults with chronic-phase chronic myeloid leukaemia treated with tyrosine kinase inhibitors

IntroductionFew studies have reported the outcomes of adolescents and young adults (AYAs) with chronic-phase chronic myeloid leukaemia (CML-CP) on tyrosine kinase inhibitors (TKIs).Materials and methodsWe retrospectively analysed the clinical features, treatment response, and long-term outcomes of 42 AYA patients, in comparison to older patients. The initial therapies of AYA patients between 2001 and 2016 included imatinib (n = 24), dasatinib (n = 13) and nilotinib (n = 5).ResultsIn AYA patients, the peripheral blood (PB) white blood cell count and percentage of blasts at the diagnosis were significantly higher, haemoglobin levels were lower and the spleen size was larger. The major molecular response (MMR), event-free survival (EFS) and overall survival (OS) rates were comparable. A sub-analysis comparing imatinib to second-generation TKIs as the initial therapy also showed that their prognosis was comparable.DiscussionIn conclusion, the tumour burden at the diagnosis of CML-CP is higher in AYA patients; however, their prognosis was not worse in comparison to older patients treated with TKIs.

KEY MESSAGES

• Few studies have reported the outcomes of adolescents and young adults (AYAs) with chronic-phase chronic myeloid leukaemia (CML-CP) on tyrosine kinase inhibitors (TKIs). This study showed the tumour burden at the diagnosis of CML-CP is higher in AYA pa tients; however, their prognosis was not worse in comparison to older patients treated with TKIs. Understanding the biological and non-biological features of AYA patients with CML-CP on TKI therapy is essential for better management and to improve the outcomes.

     

Cost-Utility Analysis of Dasatinib and Nilotinib in Patients With Chronic Myeloid Leukemia Refractory to First-Line Treatment With Imatinib in Thailand

Background

Recently, the second-generation tyrosine kinase inhibitors dasatinib and nilotinib have emerged as alternative treatments in patients with chronic myeloid leukemia (CML) who are resistant to or intolerant of imatinib.

Objective

This article aimed to assess the cost utility and budget impact of using dasatinib or nilotinib, rather than high-dose (800-mg/d) imatinib, in patients with chronic phase (CP) CML who are resistant to standard-dose (400-mg/d) imatinib in Thailand.

Methods

A Markov simulation model was developed and used to estimate the lifetime costs and outcomes of treating patients aged ≥38 years with CP-CML. The efficacy parameters were synthesized from a systematic review. Utilities using the European Quality of Life–5 Dimensions tool and costs were obtained from the Thai CML population. Costs and outcomes were compared and presented as the incremental cost-effectiveness ratio in 2011 Thai baht (THB) per quality-adjusted life year (QALY) gained. One-way and probabilistic sensitivity analyses were performed to estimate parameter uncertainty.

Results

From a societal perspective, treatment with dasatinib was found to yield more QALYs (2.13) at a lower cost (THB 1,631,331) per person than high-dose imatinib. Nilotinib treatment was also found to be more cost-effective than high-dose imatinib, producing an incremental cost-effectiveness ratio of THB 83,328 per QALY gained. This treatment option also resulted in the highest number of QALYs gained of all of the treatment options. The costs of providing dasatinib, nilotinib, and high-dose imatinib were estimated at THB 5 billion, THB 6 billion, and THB 7 billion, respectively.

Conclusions

Treatment with dasatinib or nilotinib is likely to be more cost-effective than treatment with high-dose imatinib in CP-CML patients who do not respond positively to standard-dose imatinib in the Thai context. Dasatinib was found to be more cost-effective than nilotinib.     

Burden of Infections Among Chronic Myeloid Leukemia Patients Receiving Dasatinib or Nilotinib: A Real-World Retrospective Healthcare Claims Study in the United States

Introduction

Tyrosine kinase inhibitors (TKI) have been demonstrated to prolong survival in patients with chronic myeloid leukemia (CML). However, TKIs may be associated with an increased risk of infections. This study compared healthcare resource utilization (HRU) and costs among patients with CML receiving dasatinib or nilotinib, with a focus on infection-related economic outcomes.

Methods

Two large administrative databases were used to identify adult patients newly diagnosed with CML who initiated dasatinib or nilotinib as first- (1L) or second-line (2L) therapy and were classified into the following 1L (dasatinib 1L/nilotinib 1L cohorts) or 2L (dasatinib 2L/nilotinib 2L) cohorts based on the initiated 1L/2L TKI therapy. Infection-related HRU and healthcare costs were compared between cohorts, separately for 1L and 2L.

Results

Cohorts included 1156 patients in the dasatinib 1L and 677 patients in the nilotinib 1L cohorts, 322 patients in the dasatinib 2L, and 207 in the nilotinib 2L cohorts. In 1L and 2L, infection-related HRU was higher for dasatinib than nilotinib cohorts. Infection-related inpatient (IP) days constituted a larger proportion of all-cause IP days in the 1L/2L dasatinib than 1L/2L nilotinib cohorts (dasatinib 1L/2L: 53%/58%; nilotinib 1L/2L: 50%/46%). Compared to the nilotinib cohort, the dasatinib cohort had higher all-cause total costs per patient per year by US$17,901 in 1L and $28,625 in 2L. Of the total cost difference, infection-related were $6048 (34%) in 1L and $28,192 (99%) in 2L, largely driven by IP cost differences (1L/2L: 96%/98%).

Conclusions

Dasatinib was associated with higher HRU and healthcare costs compared to nilotinib, particularly related to infections.

Funding

Novartis Pharmaceutical Corporation.

     

尼洛替尼和达沙替尼作为二三线药物治疗慢性髓性白血病慢性期和加速期患者的疗效及影响因素分析

目的分析二代酪氨酸激酶抑制剂(TKI)尼洛替尼和达沙替尼作为二三线药物治疗慢性髓性白血病(CML)慢性期(CP)和加速期(AP)患者的治疗反应和预后,以及相关影响因素。方法回顾性分析2008年1月至2018年11月北京大学人民医院收治的一二线TKI治疗失败并接受尼洛替尼或达沙替尼作为二三线治疗的CML-CP和AP患者资料。结果共收集183例尼洛替尼和达沙替尼作为二线治疗和43例尼洛替尼和达沙替尼作为三线治疗的CML-CP或AP患者。二线TKI治疗患者中,中位随访21(1~135)个月,完全血液学反应(CHR)率为80.4%,完全细胞遗传学反应(CCyR)率为56.3%,主要分子学反应(MMR)率为38.3%,3年疾病无进展生存(PFS)和总生存(OS)率分别为78.7%和93.1%。二线TKI治疗中,Sokal积分为高危、女性、一线TKI治疗期间获得最佳反应相似文献   

尼洛替尼治疗伴V299L突变的慢性髓性白血病二例

本研究提高对尼洛替尼治疗伊马替尼耐药伴V299L突变的慢性髓系白血病（chronicmyeloidleukemia,CML）患者的临床认识。收集我院2例伴V299L突变的CML患者尼洛替尼治疗前后的骨髓标本,采用巢式PCR扩增并测序的方法检测A砚突变,分析临床特征。结果表明,2例伊马替尼耐药的CML患者均发生V299L突变,1例经尼洛替尼治疗6个月后V299L突变转为阴性,并取得完全血液学缓解;另1例经尼洛替尼治疗7个月后V299L突变转为阴性,并取得明显分子学缓解。结论：尼洛替尼治疗伊马替尼耐药伴V299L突变的CML患者安全性和疗效令人满意。     

Simultaneous quantification of dasatinib,nilotinib, bosutinib,and ponatinib using high‐performance liquid chromatography–Photodiode array detection

BackgroundDasatinib, nilotinib, and bosutinib, second‐generation tyrosine kinase inhibitors (TKIs), and ponatinib, a third‐generation TKI, are approved pharmaceuticals used in the treatment of chronic myeloid leukemia (CML). Although liquid chromatography‐tandem mass spectrometry assays for simultaneous quantification of the four TKIs in human serum have been reported in the literature, a high‐performance liquid chromatography (HPLC) assay that simultaneously quantifies these compounds has not yet been developed. This study aims to establish and validate an efficient HPLC analytical method using a photodiode array (PDA) detector for the simultaneous quantification of the four TKIs.MethodsCalibration standards were prepared by serial dilution of serum samples containing the four TKIs, followed by solid‐phase extraction. The four TKIs were eluted in order within 10 min using a binary HPLC gradient system.ResultsThe calibration ranges were 2–500 ng/ml for dasatinib, 100–5000 ng/ml for nilotinib, and 10–500 ng/ml for bosutinib and ponatinib. Intra‐day and inter‐day precision and accuracy values were found to be in accordance with the U.S. Food and Drug Administration guidelines. The recovery rates were 92.9%–96.0%, 80.7%–86.1%, 91.6%–99.0%, and 86.4%–92.6% for dasatinib, nilotinib, bosutinib, and ponatinib, respectively.ConclusionTo the best of our knowledge, this is the first report of an HPLC‐PDA analytical method that allows efficient simultaneous quantification of the four TKIs in the serum of patients with CML. We believe that the method developed herein can improve the efficiency of therapeutic drug monitoring in patients with CML in clinical practice.     

Identification of side effects associated with intolerance to BCR-ABL inhibitors in patients with chronic myeloid leukemia

Clinical intolerance occurs when the toxicity of a medication outweighs its clinical benefit. Early recognition of clinical intolerance to BCR-ABL inhibitors used for chronic myeloid leukemia (CML) is important for maximizing patient benefit. In CML, most side effects associated with BCR-ABL inhibitor therapy are mild and easily managed, so recognizing, monitoring, and addressing serious side effects may ensure optimal outcome. However, a subset of patients will be intolerant to first-line imatinib. Patients who experience unresponsive grade 3 or any grade 4 nonhematologic side effects to imatinib may require discontinuation and switching to second-line therapies, such as dasatinib or nilotinib, after identification of intolerance. The most common side effects associated with dasatinib and nilotinib are hematologic and generally are reversible with dose adjustment. Pleural effusions are more common with dasatinib use and may be managed by dose interruption and reduction. Both drugs possess warnings regarding QT prolongation, but nilotinib carries a black box warning for QT prolongation and sudden death.     

Quality of life outcomes in patients with chronic myeloid leukemia treated with tyrosine kinase inhibitors: a controlled comparison

Purpose

Tyrosine kinase inhibitors (TKIs) are now standard treatment for chronic myeloid leukemia (CML). While TKIs have less toxicity than previous treatments, they have side effects that can impact quality of life (QOL).

Methods

This study compared CML patients taking a TKI for an average of 4.01 years (range 0.50–9.79 years) to age- and gender-matched controls with no history of cancer on measures of symptom burden, depression, fatigue, sleep, and health-related QOL.

Results

Compared to controls (n?=?62), CML patients (n?=?62) taking a TKI (imatinib 55 %, nilotinib 31 %, and dasatinib 14 %) reported significantly worse fatigue severity (p?<?.001), fatigue interference (p?<?.001), depression (p?=?.007), symptom burden (p?<?.001), and physical QOL (p?<?.001). TKI patients were also more likely meet established cutoffs for clinically meaningful fatigue (p values?<?.001) and depression (p?=?.004). There were no differences in mental QOL or sleep (p values?>?.010). Regarding specific symptoms, TKI patients were more likely to report nausea, diarrhea, itching, skin changes, swelling of arms or legs, and not looking like themselves (p values?<?.001).

Conclusions

These data suggest the need for interventions to address QOL in CML patients taking TKIs.     

Simultaneous determination of nine tyrosine kinase inhibitors by 96-well solid-phase extraction and ultra performance LC/MS-MS

BackgroundTyrosine Kinase Inhibitors (TKIs) are a class of targeted drugs for the treatment of malignant pathologies. The metabolic profile of these drugs can result in great interindividual variability, thus therapeutic drug monitoring (TDM) is of importance. Here, a rapid and specific method for quantification of nine TKIs in plasma samples is described.MethodsChromatography was performed on a Waters Acquity-UPLC® system with BEH C18-50*2.1 mm column, under a gradient of ammonium formate–acetonitrile. An Acquity-TQD® with electrospray ionization was used for detection. Samples were prepared by solid phase extraction (Oasis® MCX μElution) and eluate was injected in the system.ResultsCalibration curves ranged from 10 to 5000 ng/mL for imatinib, its metabolite, nilotinib, lapatinib, erlotinib and sorafenib and from 0.1 to 200 ng/mL for dasatinib, axitinib, gefitinib and sunitinib. Peaks of each compound (retention time from 0.76 to 2.51 min) were adequately separated. The mean relative extraction recovery was in the range of 90.3–106.5% thanks to the use of stable isotopes as internal standard. There was no significant ion suppression observed at the respective TKI retention times.ConclusionThis rapid, sensitive and specific UPLC/MS-MS method is able to perform simultaneous quantification of nine TKIs in human plasma and usable for routine TDM.     

A Higher Dose of Dasatinib May Increase the Possibility of Crossing the Blood–brain Barrier in the Treatment of Patients With Philadelphia Chromosome–positive Acute Lymphoblastic Leukemia

PurposeDasatinib is a second-generation tyrosine kinase inhibitor with higher central nervous system (CNS) penetration compared with imatinib and nilotinib in in vitro studies. However, limited clinical data are available regarding the dosage and CNS penetration of dasatinib. The purpose of this study was to investigate the actual ability of dasatinib to cross the blood–brain barrier in patients with Philadelphia chromosome–positive acute lymphoblastic leukemia (Ph⁺ ALL).MethodsPlasma and cerebrospinal fluid (CSF) samples collected from Ph⁺ ALL patients treated with dasatinib were analyzed by using an LC-MS/MS assay.FindingsOrally administered dasatinib 100 mg once daily was well absorbed by the patient but penetrated poorly into the CSF. The use of a higher drug dosage (140 mg/d) may increase systemic drug exposure and enhance the penetration of dasatinib into the CSF.ImplicationsBased on this study, the use of a higher dosage of dasatinib (140 mg/d) is recommended in patients at high risk of CNS relapse or patients who need treatment for CNS leukemia. ClinicalTrials.gov identifier: NCT02523976.     

Preferable timing of therapeutic drug monitoring in patients with impaired renal function treated with once-daily administration of vancomycin

The aim of this study was to investigate the timing of therapeutic drug monitoring (TDM) in patients with impaired renal function treated with once-daily administration of vancomycin (VCM). Once-daily administration was selected for patients whose creatinine clearance (C_cr) was <80 ml/min. TDM was conducted on day 3 or on day 4. Adult patients whose VCM dosage was not altered according to initial C _min and for whom subsequent follow-up TDM was performed within 1 week were entered into the study. Patients whose renal function deteriorated at follow-up TDM were excluded. One hundred sixty-five patients were eligible for analysis. Among patients with once-daily dosing, relative increases of C _min at follow-up TDM compared with initial TDM were 34.5 ± 39.2 % in TDM on day 3 and 16.6 ± 20.6 % in TDM on day 4 (P = 0.016). In contrast, there was no significant difference in the relative increase of C _min between TDM on days 3 and 4 (26.1 ± 39.6 vs. 18.4 ± 25.6 %, P = 0.551) in the twice-daily regimen. On multivariate analysis, TDM on day 3 alone (odds ratio, 4.93; 95 % confidence interval, 1.71–14.2) was selected as an independent risk factor associated with a relative increase of C _min by >30 % in the once-daily regimen. Steady-state VCM serum concentration was not achieved on day 3 in the once-daily regimen in patients with impaired renal function, and TDM on day 3 caused underestimation of C _min.     

Antidiabetic Effects of the Senolytic Agent Dasatinib

ObjectiveTo evaluate the antidiabetic effects of the senolytic agent dasatinib in older patients with type 2 diabetes mellitus.MethodsThis retrospective cohort study included enterprise-wide Mayo Clinic patients using Informatics for Integrating Biology at the Bedside from January 1994 through December 2019. The antidiabetic outcomes (change in hemoglobin A_1c value, serum glucose concentration, and diabetic medications) after 1 year of a strongly senolytic tyrosine kinase inhibitor, dasatinib (n=16), was compared with a weakly senolytic tyrosine kinase inhibitor, imatinib (n=32).ResultsRelative to imatinib, patients treated with dasatinib had a mean reduction of 43.7 mg/dL (P=.005) in serum glucose concentration (to convert glucose values to mmol/L, multiply by 0.0555) and required 28.8 fewer total daily insulin units (P=.08) in the setting of a 4.8-kg relative weight loss (5.3% of total body weight; P=.045). Linear regression analysis suggests that the relative difference in weight accounts for 8.4 mg/dL of the 43.7 mg/dL blood glucose value decrease, or 19.2%. Relative to imatinib, patients treated with dasatinib had a mean 0.80 absolute point (P=.05) reduction in hemoglobin A_1c and required 18.2 fewer total daily insulin units (P=.16) in the setting of a 5.9-kg relative weight loss (6.3% of total body weight; P=.06).ConclusionDasatinib may have antidiabetic effects comparable to contemporary diabetic treatments and may be considered for use as a novel diabetic therapy. Future studies are needed to determine whether these results are translatable to patients with type 2 diabetes mellitus without underlying malignant diseases and to determine whether the antidiabetic effects of dasatinib are due to its senolytic properties.     

Developmental Therapeutics Consortium report on study design effects on trial outcomes in chronic myeloid leukaemia

Eur J Clin Invest 2012; 42 (9): 1016-1026 ABSTRACT: Background Tyrosine kinase inhibitors (TKIs) have dramatically changed the treatment of chronic myeloid leukaemia (CML). Results from ongoing phase 3 trials with nilotinib [Efficacy and Safety in Clinical Trials-Newly Diagnosed Patients (ENESTnd)] and dasatinib [Dasatinib Versus Imatinib Study in Treatment-Naive CML-CP Patients (DASISION)] in newly diagnosed patients with CML in chronic phase have demonstrated that these TKIs resulted in significant improvements in responses vs. imatinib. Design The Developmental Therapeutics Consortium (DTC) systematically reviewed the published literature to provide a comparative analysis of the ENESTnd and DASISION trial designs and data reported on each study. Results The recent approval of nilotinib and dasatinib based on these two pivotal studies offers physicians the option to optimise frontline treatment based on a patient's comorbidities, risk factors and tolerability profiles. Although nilotinib and dasatinib provide effective therapeutic options for the frontline treatment of CML, the lack of an evidenced-based, side-by-side comparison makes it difficult to directly compare these agents. Conclusions Despite potential bias from differences in patient populations and study design, indirect cross-trial comparisons to determine the relative effectiveness of these agents will be performed by physicians. This DTC report provides a comprehensive summary of the study designs, protocols and results of the ENESTnd and DASISION trials, which will assist physicians in making informed decisions on the best treatment approach for their patients.     

Interactions of tyrosine kinase inhibitors with organic cation transporters and multidrug and toxic compound extrusion proteins

The drug-drug interaction (DDI) potential of tyrosine kinase inhibitors (TKI) as interacting drugs via transporter inhibition has not been fully assessed. Here, we estimated the half maximal inhibitory concentration (IC(50)) values for 8 small-molecule TKIs (imatinib, dasatinib, nilotinib, gefitinib, erlotinib, sunitinib, lapatinib, and sorafenib) on [(14)C]metformin transport by human organic cation transporters (OCT), OCT1, OCT2, and OCT3, and multidrug and toxic compound extrusion (MATE) proteins, MATE1 and MATE2-K, using human embryonic kidney cells stably expressing these transporters. We then compared the estimated IC(50) values to the maximum clinical concentrations of unbound TKIs in plasma (unbound C(max,sys,p)). Results showed that imatinib, nilotinib, gefitinib, and erlotinib exerted selectively potent inhibitory effects, with unbound C(max,sys,p)/IC(50) values ≥0.1, on MATE1, OCT3, MATE2-K, and OCT1, respectively. In comparison to the common form of OCT1, the OCT1 polymorphism, M420del, was more sensitive to drug inhibition by erlotinib. Major metabolites of several TKIs showed IC(50) values similar to those for unchanged TKIs. Taken together, these findings suggest the potential of clinical transporter-mediated DDIs between specific TKIs and OCTs and MATEs, which may affect the disposition, efficacy, and toxicity of metformin and other drugs that are substrates of these transporters. The study provides the basis for further clinical DDI studies with TKIs.     

Clinical practice guidelines for therapeutic drug monitoring of arbekacin: A consensus review of the Japanese Society of Chemotherapy and the Japanese Society of Therapeutic Drug Monitoring

Arbekacin (ABK) was approved and widely used in Japan for treatment of patients infected with MRSA, and TDM was introduced in clinical practice. The Japanese Society of Chemotherapy and the Japanese Society of Therapeutic Drug Monitoring decided to develop a clinical practice guidelines for TDM of ABK for the following reasons. First, although the daily dose of 150–200 mg was approved in Japan, recent PK-PD studies revealed that higher serum concentration is required to achieve better clinical efficacy and several findings concerning the usefulness of higher dosage regimen have obtained recently. Second, although maximal concentrations that obtained immediately after the end of administration (C_max) was generally adopted, the serum concentration at 1 h after initiation of administration [peak serum concentration (C_peak)] proved to be more suitable as an efficacy indicator of aminoglycosides. Lastly, as ABK is approved only in Japan, no international practice guideline for TDM has not been available in ABK to date. This guideline evaluated the scientific data associated with serum ABK monitoring and provided recommendations based on the available evidence. Potential limitations of this guideline, however, include the findings that few prospective clinical trials of TDM of ABK are available in the treatment of MRSA infections and that most of the published literature describes observational studies.     

一代和二代酪氨酸激酶抑制剂治疗 对CML染色体的影响及疗效

目的 探讨一代和二代酪氨酸激酶抑制剂治疗对慢性粒细胞白血病(CML)患者染色体的影响及疗效。方法 用常规细胞遗传学法对80例Ph+的CML患者进行遗传学分析,同时对比一代和二代酪氨酸激酶抑制剂治疗后CML患者染色体的改变情况及疗效。结果 80例Ph+的CML患者中有11例合并其他的染色体数目及结构异常,其中有10例对伊马替尼耐药或不耐受。伊马替尼(TKI-Ⅰ)治疗的40例患者中有35例达到持续完全细胞遗传学缓解(complete cytogenetic remission,CCyR)(占87.5%),其中有7例3个月时获得CCyR(占17.5%),10例6个月时获得CCyR(占25%),13例12个月时获得CCyR(占32.5%),5例18个月时获得CCyR(占12.5%); 达沙替尼/尼罗替尼(TKI-Ⅱ)治疗的40例患者中有33例达到持续完全细胞遗传学缓解(CCyR)(占82.5%),其中有16例3个月时获得CCyR(占40%),9例6个月时获得CCyR(占22.5%),5例12个月时获得CCyR(占12.5%),3例18个月时获得CCyR(占7.5%)。结论 合并其他染色体异常的Ph+CML患者更容易对伊马替尼产生耐药或不耐受性,尤其是加速期和急变期,一代和二代酪氨酸激酶抑制剂对CML的治疗在长期疗效上相差不大,但近期效果二代优于一代。     

Targeting autophagy potentiates tyrosine kinase inhibitor–induced cell death in Philadelphia chromosome–positive cells, including primary CML stem cells

Imatinib mesylate (IM), a potent inhibitor of the BCR/ABL tyrosine kinase, has become standard first-line therapy for patients with chronic myeloid leukemia (CML), but the frequency of resistance increases in advancing stages of disease. Elimination of BCR/ABL-dependent intracellular signals triggers apoptosis, but it is unclear whether this activates additional cell survival and/or death pathways. We have shown here that IM induces autophagy in CML blast crisis cell lines, CML primary cells, and p210^BCR/ABL-expressing myeloid precursor cells. IM-induced autophagy did not involve c-Abl or Bcl-2 activity but was associated with ER stress and was suppressed by depletion of intracellular Ca²⁺, suggesting it is mechanistically nonoverlapping with IM-induced apoptosis. We further demonstrated that suppression of autophagy using either pharmacological inhibitors or RNA interference of essential autophagy genes enhanced cell death induced by IM in cell lines and primary CML cells. Critically, the combination of a tyrosine kinase inhibitor (TKI), i.e., IM, nilotinib, or dasatinib, with inhibitors of autophagy resulted in near complete elimination of phenotypically and functionally defined CML stem cells. Together, these findings suggest that autophagy inhibitors may enhance the therapeutic effects of TKIs in the treatment of CML.