Second-generation BCR-ABL Tyrosine Kinase Inhibitors Research Articles

Nilotinib exhibits less toxicity than imatinib and influences the immune state by modulating iNOS, p-p38 and p-JNK in LPS/IFN gamma-activated macrophages

In this study, we aimed to analyze the effects of first and second-generation Bcr-Abl tyrosine kinase inhibitors, imatinib and nilotinib on LPS/IFN gamma activated RAW 264.7 macrophages. Our data revealed that imatinib was less effective on nitrite levels and more toxic on macrophages compared to nilotinib. Therefore, we further analysed the effect of nilotinib on various inflammatory markers including iNOS, COX-2, NFkB, IL-6, p-ERK, p-p38 and p-JNK in LPS/IFN gamma activated RAW264.7 macrophages. Spectrophotometric viability test and Griess assay,western blot, RT-PCR and luciferase reporter assays were used to analyze the biological activity of nilotinib. Our findings revealed that nilotinib decreases nitrite levels, iNOS mRNA, iNOS and p-p38 protein expressions significantly whereas induces IL-6 mRNA and p-JNK protein expressions at particular doses. We did not find significant effect of nilotinib on COX-2, p-ERK and nuclear p65 proteins and NFkB transcriptional activity. In addition, the binding mode of nilotinib to iNOS protein was predicted by molecular docking. According to the docking analyses, nilotinib exhibited hydrophobic interactions between MET349, ALA191, VAL346, PHE363, TYR367, MET368, CYS194, TRP366 residues at the binding pocket and the molecule as well as van der Waals interactions at specific residues. In conclusion, our results reveal that, in addition to its anticancer activity, nilotinib can exhibit immune modulatory effects on macrophages through its effects on iNOS, IL-6, p-p38 and p-JNK.

Protective effect of Bosutinib with caspase inhibitors on human K562 cells

IntroductionCancer therapy has become increasingly focused on molecularly targeted medications. Despite the fact that multi-cytotoxic medication regimens have proven to be highly effective, many investigations in targeted treatments have focused on a single agent. The precise molecular mechanism of action of second-generation BCR–ABL tyrosine kinase inhibitors, which includes different targets and pathways, can help rationalize therapy in chronic myelogenous leukemia (CML) and other diseases affected by BCR–ABL tyrosine kinase inhibitors (TKIs). AimThe purpose of this study was to analyze if bosutinib (BOS) combined with Boc-D-FMK effectively suppressed proliferation and induced apoptosis in K562 cells to a lesser extent, implying that bosutinib is an effective leukemia treatment and that its combination with Boc-D-FMK is a mild chemotherapeutic agent against leukemia. MethodsIn this study, bosutinib was obtained together with other materials to perform a cell culture experiment with human cell lines, as well as additional drug treatment. Furthermore, cell viability (MTT assay) and flow cryometry such as viability and cell cycle assays are performed. The target profile of the dual SRC/ABL inhibitor bosutinib was studied in this study as a first kinase inhibitor to target K562 cells, which has recently been linked to the proliferation of myelogenous leukaemia cells, these results suggest the effectiveness of inhibitory activity on cell viability/proliferation, alone generated a potent value of 250 nM (39.27 ± 1.17) for 48 h as optimal dose. ResultsThe cytotoxic effect of bosutinib on the K562 cell line was assessed in vitro using the MTT assay, and the cytotoxicity was further clarified using cell viability and cell cycle assays. Guava Cell Assay software validated the activation of apoptosis. Sub-G1, G0/G1, S, and G2/M phases are depicted. Cell cycle research revealed that K562 cells treated with bosutinib accumulated much more in the sub-G1 phase, which was later validated by a drop peak at the G2/M phase. ConclusionIn conclusion, the nature of bosutinib's reduction of cancer cell growth may open the door to future research into the development of green synthesis medicines, particularly for cancer treatment.

Vasospastic angina in a chronic myeloid leukemia patient treated with nilotinib

BackgroundNilotinib, a second-generation BCR-ABL tyrosine kinase inhibitor (TKI), is highly effective in the treatment of patients with chronic myeloid leukemia (CML), despite being more vasculotoxic than older TKIs such as imatinib. Herein, we present a case of nilotinib-associated vasospastic angina confirmed by an acetylcholine spasm provocation test.Case presentationA 62-year-old CML patient treated with 300 mg nilotinib twice daily complained of several episodes of rest angina and was hospitalized at our institution. Coronary angiography revealed no severe organic stenosis, and the acetylcholine spasm provocation test confirmed the diagnosis of vasospastic angina. Although treatment with a calcium channel blocker and nicorandil reduced the frequency of chest pain, angina symptoms continued to occur. At 10 months post discharge, the patient complained of increased frequency of angina; therefore, the nilotinib dosage was reduced to 150 mg twice daily. Consequently, the patient reported a significant improvement in chest symptoms.ConclusionsThis case report highlights the potential vasculotoxic effects of nilotinib. Cardiologists and hematologists should be vigilant for coronary artery spasm as a possible vascular adverse event caused by nilotinib.

Real-world management of chronic myeloid leukemia in South Korea: the TARGET survey.

BackgroundThe global TARGET survey examined real-world management of chronic myeloid leukemia (CML) compared with international guideline recommendations. This report focused on the responses of physicians from South Korea compared with those of physicians from the rest of the world (ROW).MethodsThe self-administered, online survey, comprising 23 questions and clinical case scenarios, was completed between April and August 2017. It was designed to gather information on practicing physicians and local practices for CML diagnosis, disease monitoring, treatment, and adverse event (AE) management.ResultsWhile there were similarities in the mutation analysis and treatment efficacy between Korea and the ROW, there were also differences in CML management. Initial diagnostic testing was more comprehensive in Korea than in the ROW, and there was significantly better access to standardized polymerase chain reaction testing. Assessment of BCR-ABL levels during the first 12 months of treatment was excellent in Korea, and there was greater frontline use of second-generation BCR-ABL tyrosine kinase inhibitors. Korean physicians were significantly less likely to switch therapy for hematologic AEs. Treatment-free remission was not an important goal of therapy among Korean or ROW physicians.ConclusionThis study identified some differences in the current CML management between Korea and the ROW; CML management in Korean patients was generally in line with the current guidelines.

Long-Term Survival, Vascular Occlusive Events and Efficacy Biomarkers of First-Line Treatment of CML: A Meta-Analysis.

Large randomized clinical trials and prior meta-analyses indicate that second-generation BCR-ABL tyrosine kinase inhibitors (TKIs) improve surrogate biomarkers in patients with chronic myeloid leukemia (CML) without providing survival benefits. The objective is to evaluate the long-term efficacy and the occurrence of vascular occlusion with second-generation BCR-ABL TKIs compared with imatinib in patients with CML. Three scientific databases, a clinical registry and abstracts from congress were searched to identify all randomized controlled trials that compared a second-generation BCR-ABL TKI to imatinib in patients with CML. Outcomes extracted were overall survival, major molecular response and complete cytogenetic response, arterial occlusive events and venous thromboembolism. These data were synthesized by odds ratios using a fixed-effect model. This meta-analysis included 4659 participants from 14 trials. Second-generation BCR-ABL TKIs did not improve overall survival compared with imatinib, even at longer follow-up (OR, 1.17 (95% CI, 0.91–1.52)). They improved surrogate biomarkers at 12 and 24 months but increased the risk of arterial occlusion (ORPETO, 2.81 (95% CI, 2.11–3.73)). The long-term benefits of second-generation TKIs are restricted to surrogate outcomes and do not translate into prolonged survival compared to imatinib. Given the long-term use, frontline therapy should be chosen carefully, with special attention to the patients’ quality of life and cardiovascular risks.

Characteristics of Trials and Regulatory Pathways Leading to US Approval of Innovative vs. Non-Innovative Oncology Drugs

Background: Successful first-generation drugs can be updated or copied with small alterations to make drugs, which are less expensive to develop and carry less financial risk for manufacturers, since the mechanism of action has been validated and a well-defined consumer market exists. We compared the pivotal clinical trials and FDA approval pathways for first- and second-generation cancer drugs. Methods: Among cancer drugs approved in the US from 1994-2014, we found four classes of oncology drugs in which second-generation products followed many years after the first-generation agents: BCR-ABL tyrosine kinase inhibitors for treatment of chronic myelogenous leukemia, ALK tyrosine kinase inhibitors for non-small cell lung cancer, CD20 monoclonal antibodies for chronic lymphocytic leukemia and HER2 monoclonal antibodies for breast cancer. From information on these 13 drugs available in documents published by FDA at the time of approval, we extracted the following characteristics: approval pathway, pivotal trial design, number of participants, efficacy endpoints, and outcomes. Findings: The first-generation and 3 out of 4 second-generation BCR-ABL tyrosine kinase inhibitor drugs were granted expedited approval, while all 4 drugs were approved based on single-arm pivotal trials. Both ALK tyrosine kinase inhibitor drugs were based on single-arm trials and expedited regulatory review. The first-generation CD20 monoclonal antibody drug was approved based on single-arm trials, and 1 of the 2 second-generation drugs had pivotal trials that were randomized. All benefited from expedited approval. All 3 HER2 monoclonal antibodies in the sample were based on randomized trials and expedited pathways. Interpretation: Second-generation tyrosine kinase inhibitors and monoclonal antibodies used in cancer treatment were often approved through expedited approval pathways and studied in single-arm trials. Such pathways help facilitate the approval of these products for earlier use by patients, but are also associated with greater risk of post-approval safety-related labeling changes or unanticipated adverse events. Funding Statement: Dr. Kesselheim's work is funded by the Laura and John Arnold Foundation, with additional support from the Harvard Program in Therapeutic Science and the Engelberg Foundation. Dr. Vokinger's work is funded by the Swiss National Foundation. Declaration of Interest: The authors have declared no conflicts of interest.

Retrospektywna analiza skuteczności nilotynibu i dazatynibu w drugiej linii terapii przewlekłej białaczki szpikowej w polskich ośrodkach hematologicznych

Until now, there has been no randomized study directly comparing the activity of second-generation BCR-ABL tyrosine kinase inhibitors (TKI-2G) nilotinib and dasatinib in chronic myeloid leukemia (CML). The aim of our study was to retrospectively analyze efficacy of nilotinib and dasatinib in the real life setting of CML with resistance or intolerance of imatinib. Of 108 included patients treated in polish hematology centers, 75 received dasatinib and 33 patients received nilotinib. Rates of complete cytogenetic response (CCyR) did not differ between the two groups of patients. After six months of therapy, CCyR was achieved in 34.7% of patients treated with dasatinib and 38.7% treated with nilotinib (p=0.86), while after 12 months, the CCyR rates were 60.0% and 77.0% in dasatinib and nilotinib groups, respectively (p=0.11). Moreover, we have not observed any significant difference in the probability of progression-free survival (p=0.89) or overall survival (p=0.99) between patients treated with these two TKI-2G. In conclusion, the results of our analysis indicate that nilotinib and dasatinib have comparable and satisfactory efficacy in the treatment of CML patients refractory or intolerant to imatinib. Our findings support current strategy of choice of IKT-2G according to drug toxicity profile and risk of specific adverse events in an individual patient.

Clinical features of pulmonary arterial hypertension in patients receiving dasatinib.

The prognosis of most leukemia patients treated with BCR-ABL tyrosine kinase inhibitors (TKIs) is favorable, and a more precise understanding of serious and potentially irreversible treatment-related toxicities is essential to properly inform treatment choice. Few cases of pulmonary arterial hypertension (PAH) have been reported in patients with leukemia treated with dasatinib, a second-generation BCR-ABL TKI. To better understand characteristics and outcomes of dasatinib-treated patients with PAH, all clinical cases of PAH confirmed by right-heart catheterization in the Bristol-Myers Squibb pharmacovigilance database (N = 41), including 22 previously unpublished cases, were examined for previous treatments for leukemia, patient characteristics, time to PAH onset, and outcomes. Our analysis shows that compared with PAH due to other etiologies, dasatinib-related PAH is atypical, in that it is associated with partial to complete reversibility upon treatment discontinuation. The incidence of dasatinib-related PAH appears to be low. Most PAH cases were observed in patients who had received prior treatments for leukemia. No specific patient attributes appear to be associated with an increased risk of developing PAH while receiving dasatinib. Symptoms of PAH in dasatinib-treated leukemia patients should prompt a thorough workup, including consideration of confirmatory right-heart catheterization. In cases of confirmed PAH, dasatinib should be discontinued.

Distinct Associations Between UGT1A1 Gene Promoter Polymorphism and Hyperbilirubinemia in Korean CML Patients Treated with Nilotinib and Radotinib

Background: Second-generation BCR-ABL tyrosine kinase inhibitors (2nd generation TKIs) including nilotinib (NIL) and radotinib (RAD) are approved for the treatment of newly diagnosed and other TKI failed chronic myeloid leukemia (CML). Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene promoter polymorphism, distinct number of TA repeats in promoter, has been reported for an association with hyperbilirubinemia on nilotinib therapy (Singer et al. Leukemia (2007) 21, 2311–2315). However, the distribution of UGT1A1 (TA)7 repeat polymorphism differs greatly between Caucasians and Japanese, namely, the frequency of UGT1A1(TA)7 repeat polymorphism is high in Caucasians, whereas it is low in Asians (Beutler et al. Proc. Natl. Acad. Sci. USA 95 (1998) 95, 8170–8174 ).Aims: The aim of this study was to investigate the association between UGT1A1 gene promoter polymorphism and hyperbilirubinemia in Korean CML patients treated with NIL and RAD as a frontline therapy.Methods: A total of 88 newly diagnosed chronic phase CML patients who treated with frontline NIL (n=39) and RAD (n=49) was screened for UGT1A1 promoter polymorphism genotype analysis. We used the High Pure PCR Template Preparation Kit (Roche, Germany) to prepare genomic DNA from whole blood and genotyped by direct sequencing of the 253- to 255-bp fragments produced by PCR.Results: The (TA)6/(TA)6 homozygote and (TA)6/(TA)7 heterozygote were seen in all genotyped population and frequency of (TA)6/(TA)6 homozygote was 79.5% (70/88) in our patients. (TA)6/(TA)6 homozygote predominated with 81.6% of the alleles in the RAD group and 76.9% in the NIL group. Relative riskfor each genotype presented in Table 1, with hyperbilirubinemia defined as CTCAE grade 2 or greater observed at any post-baseline point. The relative risks for 6/6 genotype versus 6/7 genotype was 3.5 with 95% CIs of (0.6, 18.9) in the RAD group compared with 8.1 (1.5, 43.8) in the NIL group and NIL group showed significantly high association with UGT1A1 gene promoter polymorphism (P<0.05).Conclusions: This finding suggests that UGT1A1 gene promoter polymorphism may be an important determinant of hyperbilirubinemia in CML patients with NIL therapy, but not in RAD. However other mechanisms should be explored in patients who have significant hyperbilirubinemia with RAD therapy. Updated data with longer follow-up duration will be presented in the meeting.Table 1Relative risk calculations for prevalence of hyperbilirubinemiaRadotinibNilotinibMax grade=,<1Max grade>,=2TotalMax grade=,<1Max grade>,=2Total(TA)6/(TA)6202040(TA)6/(TA)62643050.00%50.00%65.00%10.00%(TA)6/(TA)7279(TA)6/(TA)745922.22%77.78%44.44%55.56%Total222749Total30939Relative risk=3.5, 95% CI of (0.6, 18.9)Relative risk=8.1, 95% CI of (1.5, 43.8)Abbreviation: CI, confidence interval. DisclosuresNo relevant conflicts of interest to declare.

Comparison of Adherence Between Nilotinib and Dasatinib As Second-Line Therapies in Chronic Myeloid Leukemia

Abstract 2754 Background:According to the NCCN guidelines, the recommended treatment option for patients diagnosed with Philadelphia-positive (Ph+) chronic myeloid leukemia (CML) in chronic or accelerated phases who are resistant or develop intolerance to first-line imatinib is to switch to one of the two second-generation BCR-ABL tyrosine kinase inhibitors, nilotinib or dasatinib. There is limited information on their comparative adherence. Analysis of adherence may reveal whether these two drugs are being used as intended and how adherence issues may potentially affect clinical outcomes. Nonadherence to imatinib has been associated with loss of cytogenetic response, imatinib failure, and higher rates of inpatient visits. A prior study covering the period up to 6/2009 has revealed a better adherence profile for nilotinib versus dasatinib. Since dasatinib was approved for once daily use in addition to twice daily use in 05/2009, this study replicated the analysis using more recent data to compare adherence between nilotinib and dasatinib as second-line therapies in CML. Methods:Medical and pharmacy records from two databases from January 1997 to April 2010 were combined to identify adult patients diagnosed with CML (ICD-9 code 205.1x) with ≥1 prescription for either nilotinib or dasatinib. Patients were required to have continuous enrollment ≥1 month prior to and after the index date, defined as the first prescription for nilotinib or dasatinib, and to continue their treatment ≥1 month before discontinuing or switching to another TKI. Adherence over an up-to 180-day period was evaluated based on the proportion of days covered (PDC; sum of days of medication on hand for nilotinib or dasatinib divided by the number of calendar days in the study period). Medication possession ratio (MPR) was also evaluated in a sensitivity analysis. PDC and MPR were compared between cohorts using linear regression models. Discontinuation was defined as a treatment gap ≥30 days, and rates were compared between cohorts using Kaplan-Meier survival analyses and Cox proportional hazard regression models. In a sensitivity analysis, discontinuation was defined as a treatment gap ≥90 days. All multivariate regression models were controlled for age, gender, CML complexity, adverse events at baseline, number of inpatient days, emergency room (ER) visits and outpatient visits during baseline, medical costs during baseline, CML year of diagnosis, Charlson Comorbidity Index, and bone marrow or stem cell transplant before the index date. Results:Adherence and discontinuation were analyzed for a total of 558 CML patients receiving a second-line TKI (473 dasatinib and 85 nilotinib). Patient characteristics were generally similar. Patients in the dasatinib cohort had a longer mean follow-up period compared with those in the nilotinib cohort (162 days vs. 146 days; P = 0.0007) and greater utilization and costs associated with inpatient and ER services. The mean PDC over the study period for nilotinib was higher compared with dasatinib (0.81 vs 0.68). After adjusting for confounding factors, the nilotinib group had a 0.115 higher PDC (approximately 17% higher) compared to the dasatinib group (P = 0.0004). Additionally, patients in the nilotinib group had a significantly higher MPR compared to patients in the dasatinib group (0.90 vs. 0.77 P = 0.0043). Discontinuation rates (gap ≥30 days) were significantly higher for dasatinib users than for nilotinib users, with an adjusted hazard ratio of 2.15 (P = 0.0013). Dasatinib-treated patients had higher discontinuation rates than nilotinib-treated patients after 3 months (40% vs 22%) and 6 months (50% vs 28%). These unadjusted differences were robust in the sensitivity analysis with discontinuation defined as a treatment gap ≥90 days, but the difference between the cohorts was no longer significant after adjusting for confounding factors (HR 1.76, P = 0.1328). Conclusions:This retrospective study showed that CML patients treated with nilotinib for second-line treatment were significantly more adherent to therapy, based on PDC and MPR, and had a lower discontinuation rate than did patients receiving dasatinib in this analysis. Further studies are needed to better understand treatment-specific factors affecting adherence and persistence (e.g., treatment cost, tolerability profile, dosing convenience). Disclosures:Guerin:Novartis Pharmaceutical Corporation: Annie Guerin is an employee of Analysis Group, Inc, which has received research funds from Novartis Pharmaceuticals. Bollu:Novartis Pharmaceutical Corporation: Employment, Vamsi K. Bollu worked for the Novartis Pharmaceuticals Corporation while performing this analysis but is currently employed by Sunovion Pharmaceuticals Inc. Sunovion Pharmaceuticals Inc. was not in any way associated with this study. Guo:Novartis Pharmaceutical Corporation: Employment. Stepner:Novartis Pharmaceutical Corporation: Michael Stepner is an employee of Analysis Group, Inc, which has received research funds from Novartis Pharmaceuticals. Griffin:Novartis Pharmaceutical Corporation: James D. Griffin is an employee of the Dana Farber Institute which has received consultancy fees from Analysis Group, Inc, which has received research funds from Novartis Pharmaceuticals Corporation. Wu:Novartis Pharmaceutical Corporation: Eric Q. Wu is an employee of Analysis Group, Inc, which has received consultancy funds from Novartis Pharmaceutical Corporation.

Effects of Rifampin and Ketoconazole on the Pharmacokinetics of Nilotinib in Healthy Participants

Nilotinib (Tasigna), an orally bioavailable second-generation BCR-ABL tyrosine kinase inhibitor, is approved for use in patients with chronic myeloid leukemia in chronic phase and accelerated phase who are resistant or intolerant to prior therapy, including imatinib. Previous in vitro studies indicated that nilotinib metabolism is primarily mediated by CYP3A4. To investigate the effect of CYP3A4 induction and inhibition on nilotinib pharmacokinetics, 2 studies were conducted in healthy volunteers prior to and following treatment with a strong inducer (rifampin) or inhibitor (ketoconazole). In the induction study, administration of rifampin 600 mg once daily for 8 days significantly increased urinary 6β-hydroxycortisol/ cortisol ratio, from a preinduction baseline of 5.8 ± 2.7 to 18.0 ± 10.2 after 8 days of rifampin treatment, confirming an inductive effect on CYP3A4. Nilotinib oral clearance was increased by 4.8-fold, and the maximum serum concentration (C(max)) and area under the serum concentration-time curve (AUC) were decreased by 64% and 80%, respectively, in the induced state compared with baseline. In the inhibition study, ketoconazole 400 mg once daily for 6 days increased the C(max) and AUC of nilotinib by 1.8- and 3-fold, respectively, compared with nilotinib alone. These results indicate that concurrent use of strong CYP3A4 inducers or inhibitors may necessitate dosage adjustments of nilotinib and should be avoided when possible.

Effect of Grapefruit Juice on the Pharmacokinetics of Nilotinib in Healthy Participants

Nilotinib (Tasigna; Novartis Pharmaceuticals) is a second-generation BCR-ABL tyrosine kinase inhibitor newly approved for the treatment of imatinib-resistant or imatinib-intolerant Philadelphia chromosome positive (Ph+) chronic myeloid leukemia in chronic phase or accelerated phase. This study evaluated the effect of grapefruit juice on the pharmacokinetics of nilotinib in 21 healthy male participants. All participants underwent 2 study periods during which they received a single oral dose of 400 mg nilotinib with 240 mL double-strength grapefruit juice or 240 mL water in a crossover fashion. Serial blood samples were collected for the determination of serum nilotinib concentrations by a validated liquid chromatography/tandem mass spectrometry assay. Concurrent intake of grapefruit juice increased the nilotinib peak concentration (C(max)) by 60% and the area under the serum concentration-time curve (AUC(0-infinity)) by 29% but did not affect the time to reach C(max) or the elimination half-life of nilotinib. The most common adverse events were headache and vomiting, which were mild or moderate in severity, and their frequency appeared to be similar between 2 treatments. Based on the currently available information about nilotinib and the observed extent of increase in nilotinib exposure, concurrent administration of nilotinib with grapefruit juice is not recommended.

Clinical Pharmacokinetics of the BCR–ABL Tyrosine Kinase Inhibitor Nilotinib

This article describes studies that investigated the pharmacokinetics of nilotinib, a highly specific, oral, second-generation BCR-ABL tyrosine kinase inhibitor. After a once- or twice-daily regimen at doses ranging from 50 to 1,200 mg/day in 119 patients with chronic myeloid leukemia (CML), the area under the serum concentration-time curve (AUC) and peak serum concentration (C(max)) of nilotinib were found to be nearly dose proportional up to a dose of 400 mg once daily. Solubility-limited absorption at higher doses was observed, but this was partially overcome by dividing the daily dose into two. For instance, the administration of 400 mg nilotinib twice daily resulted in a 35% increase in AUC as compared to a once-daily dose of 800 mg. Exploratory pharmacodynamic assessment showed a general trend of greater reduction in white blood cell (WBC) levels with increase in nilotinib concentrations. This finding was consistent with the observation of an 82% reduction in WBC levels in patients after a regimen of 400 mg nilotinib twice daily for 15 days. The type and quantity of food intake variably affected nilotinib absorption. When administered after a high-fat meal, the AUC of nilotinib increased by 50% in CML patients (n = 10) and by 82% in healthy volunteers (n = 44).

Effects of hepatic impairment on the pharmacokinetics of nilotinib: An open-label, single-dose, parallel-group study

Background: Nilotinib is a second-generation BCR-ABL tyrosine kinase inhibitor approved for the treatment of patients who have imatinib-resistant Philadelphia chromosome-positive chronic myeloid leukemia in the chronic or accelerated phase or who are unable to tolerate imatinib. Nilotinib is metabolized in the liver via oxidation and hydroxylation pathways, mediated primarily by the cytochrome P450 3A4 isozyme. Interpatient variability in systemic exposure to nilotinib has been reported to range from 32% to 64%. Objective: This study compared the pharmacokinetics of nilotinib in subjects with hepatic impairment and subjects with normal hepatic function. Methods: Hepatic impairment was classified as mild (Child-Pugh grade A), moderate (Child-Pugh grade B), or severe (Child-Pugh grade C). Healthy control subjects were matched with hepatically impaired subjects by age (±10 years) and body weight (±20%). All subjects received a single oral dose of nilotinib 200 mg under fasted conditions, and serial blood samples were collected at specific times up to 120 hours after dosing. Serum nilotinib concentrations were measured using a validated LC-MS/MS assay with a lower limit of quantification of 2.5 ng/mL. The pharmacokinetic parameters analyzed were C max, T max, AUC 0−last, AUC 0−∞, t ½, CL/F, and Vz/F. Tolerability assessments included adverse events (AEs), regular monitoring of clinical laboratory measures (eg, hematology, blood chemistry, urinalysis), physical examinations, vital signs, and ECGs. Each AE was evaluated in terms of its clinical significance, severity, duration, relation to study drug, and action taken. Results: The study enrolled 18 subjects with hepatic impairment (all male; age range, 47–67 years; weight range, 73.9–103.9 kg) and 9 healthy controls (all male; age range, 36–62 years; weight range, 73.3–109.5 kg). Among subjects with hepatic impairment, 6 had mild impairment, 6 moderate impairment, and 6 severe impairment. The nilotinib AUC 0−∞ was a mean of 35%, 35%, and 19% higher in subjects with mild, moderate, and severe impairment, respectively, compared with healthy controls. The nilotinib CL/F was lower in all hepatic-impairment groups compared with healthy controls. The mean (SD) t ½ was 15.1 (4.97) and 16.0 (9.13) hours in the mild-impairment and control groups, respectively, but was 21.6 (7.77) and 32.4 (10.7) hours in the moderate- and severe-impairment groups, respectively, reflecting the decrease in CL/F and/or increase in Vz/F in the latter 2 groups. All AEs were mild or moderate, and the frequency of AEs was not associated with the degree of hepatic impairment. AEs included abdominal pain (1 subject with mild impairment), dyspepsia (2 with mild impairment), flatulence (1 with severe impairment), nausea (1 with mild impairment), urinary tract infection (1 with mild impairment), back pain (1 each with mild impairment and severe impairment, 1 control subject), and headache (1 each with mild impairment and severe impairment). Conclusions: After a single 200-mg dose, nilotinib pharmacokinetics were modestly affected by hepatic impairment. The extent of change in nilotinib exposure in subjects with hepatic impairment was generally within the range of variability that has been observed clinically. The results of this study suggest that dose adjustment may not be necessary in patients with hepatic impairment. Nilotinib should be used with caution, and careful clinical monitoring is recommended in this population. ClinicalTrials.gov identifier: NCT00418626.

Global target profile of the kinase inhibitor bosutinib in primary chronic myeloid leukemia cells

The detailed molecular mechanism of action of second-generation BCR-ABL tyrosine kinase inhibitors, including perturbed targets and pathways, should contribute to rationalized therapy in chronic myeloid leukemia (CML) or in other affected diseases. Here, we characterized the target profile of the dual SRC/ABL inhibitor bosutinib employing a two-tiered approach using chemical proteomics to identify natural binders in whole cell lysates of primary CML and K562 cells in parallel to in vitro kinase assays against a large recombinant kinase panel. The combined strategy resulted in a global survey of bosutinib targets comprised of over 45 novel tyrosine and serine/threonine kinases. We have found clear differences in the target patterns of bosutinib in primary CML cells versus the K562 cell line. A comparison of bosutinib with dasatinib across the whole kinase panel revealed overlapping, but distinct, inhibition profiles. Common among those were the SRC, ABL and TEC family kinases. Bosutinib did not inhibit KIT or platelet-derived growth factor receptor, but prominently targeted the apoptosis-linked STE20 kinases. Although in vivo bosutinib is inactive against ABL T315I, we found this clinically important mutant to be enzymatically inhibited in the mid-nanomolar range. Finally, bosutinib is the first kinase inhibitor shown to target CAMK2G, recently implicated in myeloid leukemia cell proliferation.

Renal failure and recovery associated with second-generation Bcr-Abl kinase inhibitors in imatinib-resistant chronic myelogenous leukemia

Tyrosine kinase inhibitors (TKIs) directed against the Bcr-Abl kinase have revolutionized the treatment of chronic myelogenous leukemia (CML). Relatively little is known regarding the effects of these agents on the kidney. Clinically, there have been a handful of reports associating imatinib with acute renal failure. Preclinical reports indicate that imatinib inhibits signaling pathways which may play a role in renal injury. We report the case of a patient with imatinib-resistant CML who developed renal failure after being placed on dasatinib. When she later became resistant to dasatinib she was switched to nilotinib. Shortly thereafter, she became dialysis-independent. Second-generation Bcr-Abl TKIs may influence renal function based on differential inhibition of related tyrosine kinases.

The Bcr-Abl kinase inhibitor INNO-406 induces autophagy and different modes of cell death execution in Bcr-Abl-positive leukemias

Bcr-Abl tyrosine kinase (TK) inhibitors are promising therapeutic agents for Bcr-Abl-positive (Bcr-Abl(+)) leukemias. Although they are known to promote caspase-mediated apoptosis, it remains unclear whether caspase-independent cell death-inducing mechanisms are also triggered. Here we demonstrated that INNO-406, a second-generation Bcr-Abl TK inhibitor, induces programmed cell death (PCD) in chronic myelogenous leukemia (CML) cell lines through both caspase-mediated and caspase-independent pathways. The latter pathways include caspase-independent apoptosis (CIA) and necrosis-like cell death (CIND), and the cell lines varied regarding which mechanism was elicited upon INNO-406 treatment. We also observed that the propensity toward CIA or CIND in cells was strongly associated with cellular dependency on apoptosome-mediated caspase activity. Cells that undergo CIND have a high apoptosome activity potential whereas cells that undergo CIA tend to have a lower potential. Moreover, we found that INNO-406 promotes autophagy. When autophagy was inhibited with chloroquine or gene knockdown of beclin1 by shRNA, INNO-406-induced cell death was enhanced, which indicates that the autophagic response of the tumor cells is protective. These findings suggest new insights into the biology and therapy of Bcr-Abl(+) leukemias.