A Validated Assay to Quantify Osimertinib and Its Metabolites, AZ5104 and AZ7550, from Microsampled Dried Blood Spots and Plasma.

BACKGROUND: Osimertinib is an oral small-molecule tyrosine kinase receptor inhibitor used to treat non-small cell lung cancer (NSCLC) with a sensitizing epidermal growth factor receptor mutation. Patients may experience drug toxicity and require dose deescalation. The study aimed to quantitate osimertinib and its 2 active metabolites, AZ5104 and AZ7550, in microsampled dried blood spots (DBS) collected from patients with NSCLC using a hemaPEN device and compare them with plasma drug levels. METHODS: A 6-min ultrahigh-performance liquid chromatography-tandem mass spectrometry method was developed and validated using plasma and DBS. The accuracy, selectivity, matrix effect, recovery, and stability were assessed using bioanalytical validation criteria. The hematocrit effect was investigated in DBS. Drug levels were measured in 15 patients with NSCLC, and the Bland-Altman method was used to compare measurements between plasma and DBS. RESULTS: The validated assay determined accurate and precise quantities, respectively, for osimertinib in both plasma (93.2%-99.3%; 0.2%-2.3%) and DBS (96.7%-99.6%; 0.5%-10.3%) over a concentration of 1-729 ng/mL. The osimertinib metabolites, AZ5104 and AZ7550, were similarly validated in accordance with bioanalytical guidelines. For 30%-60% patient hematocrit, no hematocrit bias was observed with DBS for all analytes. The Bland-Altman method showed high concordance between plasma and DBS analyte levels. Stability experiments revealed that osimertinib and its metabolites were poorly stable in plasma at room temperature, whereas all analytes were stable in DBS for 10 days at room temperature. CONCLUSIONS: The measurement of osimertinib, AZ5104, and AZ7550 from hemaPEN microsampled DBS is a convenient and reliable approach for therapeutic drug monitoring that produces measurements consistent with plasma drug levels.

Determination of the segmental hepatic clearance rate of 99mTc-mebrofenin and its application in the functional assessment of future liver remnant after liver resection.

99mTc-mebrofenin hepatobiliary scintigraphy with SPECT/CT (HBS-M) has become an important quantitative method to evaluate global liver function and future liver remnant (FLR) function in patients who are candidates for resective liver surgery. The purpose of this work was to describe the method in the prediction of post-surgical liver failure. The overall liver function and that of the FLR are obtained by analysis of the initial dynamic phase of the scan. Liver volume to be preserved is expressed as a percentage of the total liver volume measured in both CT sections. HBS-M is able to accurately gauge regional liver function abnormalities that could be represented as normal liver tissue parenchyma in the CT study. This technique can provide very valuable prognostic information for the estimation of the postoperative risk of liver failure in all patients who are candidates for resective liver surgery.

Development, validation, and application of an LC-MS/MS method for the determination of the AXL/FLT3 inhibitor gilteritinib in mouse plasma.

A simple, fast and precise LC-MS/MS method for the quantitation of the tyrosine kinase inhibitor gilteritinib was developed and validated for micro-volumes of mouse plasma. The assay procedure involved a one-step extraction of gilteritinib and the internal standard [2H5]-gilteritinib with acetonitrile. An Accucore aQ column was used to separate analytes using a gradient elution delivered at a flow rate of 0.4 mL/min, and a total run time of 2.5 min. Validation studies with quality control samples processed on consecutive days revealed that values for intra-day and inter-day precision were <7.04%, with an accuracy of 101-108%. Linear responses were observed over the entire calibration curve range (up to 500 ng/mL), and the lower limit of quantification was 5 ng/mL. The developed method was successfully used to examine the pharmacokinetics of oral gilteritinib in wild-type mice and mice lacking the organic cation transporters OCT1, OCT2, and MATE1 to further understand mechanisms contributing to drug-drug interactions and causes of inter-individual pharmacokinetic variability.

Efficacy and safety of bosutinib versus imatinib for newly diagnosed chronic myeloid leukemia in the Asian subpopulation of the phase 3 BFORE trial.

Bosutinib is approved in the United States, Europe, Japan, and other countries for treatment of newly diagnosed chronic phase (CP) chronic myeloid leukemia (CML), and CML resistant/intolerant to prior therapy. In the phase 3 BFORE trial (Clinicaltrials.gov, NCT02130557), patients were randomized 1:1 to first-line bosutinib or imatinib 400 mg once daily. We examined efficacy, safety, and patient-reported outcomes of bosutinib vs imatinib and pharmacokinetics of bosutinib in the Asian (n = 33 vs 34) and non-Asian (n = 235 vs 234) subpopulations of BFORE followed for at least 24 months. At the data cutoff date, 72.7 vs 66.7% of Asian and 70.6 vs 66.4% of non-Asian patients remained on treatment. The major molecular response rate at 24 months favored bosutinib vs imatinib among Asian (63.6 vs 38.2%) and non-Asian (60.9 vs 52.6%) patients, as did the complete cytogenetic response rate by 24 months (86.7 vs 76.7%, 81.5 vs 76.3%). Treatment-emergent adverse events in both subpopulations were consistent with the primary BFORE results. Trough bosutinib concentration levels tended to be higher in Asian patients. Health-related quality of life was maintained after 12 months of bosutinib in both subpopulations. These results support bosutinib as a first-line treatment option in Asian patients with CP CML.

Effects of SLC22A2 808G>T polymorphism and bosutinib concentrations on serum creatinine in patients with chronic myeloid leukemia receiving bosutinib therapy.

The purpose of this study was to investigate the effects of SLC22A2 808G>T polymorphism and trough concentrations (C0) of bosutinib on serum creatinine in 28 patients taking bosutinib. At 1, 3, 6, 12, 24, and 36 months after administration, analysis of bosutinib C0 and creatinine was performed at the same time of day. Significant correlations were observed between bosutinib C0 and the change rate of serum creatinine or the estimated glomerular filtration rate (eGFR; r = 0.328, P < 0.001 and r = - 0.315, P < 0.001, respectively). These correlations were particularly high in patients having the SLC22A2 808G/G genotype (r = 0.345 and r = - 0.329, respectively); however, in patients having the 808T allele, there were no significant differences. In multivariate analyses, the SLC22A2 808G/G genotype, patient age, bosutinib C0 and second-line or later bosutinib were independent factors influencing the change rate of creatinine. Bosutinib elevated serum creatinine through organic cation transporter 2 (OCT2). We observed a 20% increase in serum creatinine with a median bosutinib C0 of 63.4-73.2 ng/mL. Periodic measurement of serum creatinine after bosutinib therapy is necessary to avoid progression to severe renal dysfunction from simple elevation of creatinine mediated by OCT2 following bosutinib treatment.

High-throughput liquid chromatography/electrospray ionization-tandem mass spectrometry method using in-source collision-induced dissociation for simultaneous quantification of imatinib, dasatinib, bosutinib, nilotinib, and ibrutinib in human plasma.

Recent studies have shown that therapeutic drug monitoring of tyrosine kinase inhibitors (TKIs) could improve treatment efficacy and safety. A simple analytical method using high-performance LC/electrospray ionization-tandem mass spectrometry has been developed and validated for simultaneous quantification of BCR-ABL and Bruton's TKIs used for chronic leukemia (imatinib, dasatinib, bosutinib, nilotinib, and ibrutinib) in human plasma. Although these structures and physical properties are similar, owing to their different linear ranges, simultaneously determining the plasma levels of these five TKIs by applying optimal MS parameters remains difficult. A quantitative range exceeding 60,000-fold was required, and the linear dynamic ranges of imatinib, bosutinib, and nilotinib were limited because of the presence of a saturated detection signal. In this study, we applied the in-source collision-induced dissociation technique to control the ion amounts in mass spectrometry. This new method allowed rapid determination within 5 min with simple pretreatment. The method was validated according to the US Food and Drug Administration guidelines. Moreover, all samples of patients with chronic leukemia were successfully measured and their values were within the linear range of measurement. Therefore, our high-throughput analytical system is useful to measure the plasma concentrations of imatinib, dasatinib, bosutinib, nilotinib, and ibrutinib in clinical practice.

Determination of the concentration of gilteritinib in human plasma using HPLC.

Gilteritinib, an oral inhibitor of FMS-like tyrosine kinase 3 (FLT3), is a standard treatment for FLT3-mutated acute myeloid leukemia. We developed a simple HPLC-UV-based method for determining the concentration of gilteritinib in human plasma. The analysis requires the extraction of a 200-µL plasma sample and the precipitation of proteins by solid-phase extraction. Gilteritinib was isocratically separated within 10 min using a mobile phase of acetonitrile:0.5% monopotassium phosphate (KH2 PO4 , pH 3.5, 28:72, v/v) on a Capcell Pack C18 MG II (250 × 4.6 mm) column at a flow rate of 1.0 mL/min and monitored at 250 nm. The calibration curve was found to be linear within a plasma concentration range of 25-2500 ng/mL, with the coefficient of determination (r2 ) being 0.9997. The coefficients of intra-day and inter-day validation were 2.3-3.7 and 1.3-5.2%, respectively. The accuracy and recovery of the assay were -9.6 to 0.1 and >81.8%, respectively. This HPLC-UV method for determining the plasma concentration of gilteritinib is simple and can be effectively applied to routine drug monitoring.

Development and Validation of a LC-MS/MS Method for Quantification of Mobocertinib (TAK-788) in Plasma and its Application to Pharmacokinetic Study in Rats.

AIM AND OBJECTIVE: An analytical method for the determination of mobocertinib, an investigational tyrosine kinase inhibitor, was developed and optimized by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) in rat plasma. MATERIALS AND METHODS: Plasma samples were pretreated by the protein precipitation method with a methanol solution of osimertinib as the internal standard (IS). Chromatographic separation was performed using an Inertsil ODS-3 column (50 mm × 4.6 mm, I.D. 5 µm) with the temperature maintained at 40°C. The mobile phase consisted of water (containing 0.1% formic acid) and methanol in a gradient mode at a flow rate of 0.5 mL/min. Mass spectrometric detection was carried out in the selected reaction monitoring (SRM) mode with positive electrospray ionization, and the mass transitions of mobocertinib and osimertinib were m/z 587.01 → 71.88 and m/z 499.80 → 71.94, respectively. The method was validated in terms of selectivity, linearity, accuracy and precision, extraction recovery and matrix effect, stability and carryover as per the guidelines for bioanalytical method validation (FDA, 2018). The method was applied to the pharmacokinetic study of mobocertinib in rats by oral gavage at the doses of 2, 6, and 18 mg/kg. A total of 216 plasma samples from 18 rats were analyzed. RESULTS: The results showed good linearity over the range of 1-1000 ng/mL (R2 = 0.9957). The intra-batch accuracy was within 94.65-102.59% and the precision was within 5.49-10.46%. The inter-batch accuracy was within 97.08-102.25% with a precision of 7.54-10.13%. The extraction recovery and matrix factor were acceptable for the bioanalysis of mobocertinib. Additionally, mobocertinib was found to be stable under the detected conditions. Mobocertinib showed linear pharmacokinetic characteristics following oral administration to rats at 2.0-18.0 mg/kg. CONCLUSION: The developed and validated method was successfully employed in the pharmacokinetic study in rats following oral administration of mobocertinib at the doses of 2, 6, and 18 mg/kg.

The Impact of Hemodialysis and Liver Cirrhosis on the Plasma Concentrations of Tyrosine Kinase Inhibitors in a Patient with Chronic Myeloid Leukemia.

We recently treated a chronic myeloid leukemia (CML) patient with liver and renal dysfunction, who was undergoing hemodialysis (HD). He was treated with 50 mg dasatinib (DAS) once daily just before HD. The maximum plasma concentration of DAS was 227 ng/mL on a non-HD day and 46.9 ng/mL on a HD day. He was subsequently treated with 200 mg bosutinib (BOS) once daily. The plasma concentration of BOS changed from 74.5 ng/mL before HD to 58.8 ng/mL after HD. Our results indicate that close monitoring of the plasma tyrosine kinase inhibitor concentrations should be considered in CML patients with organ impairment.

An LC-MS/MS Bioanalytical Assay for the Determination of Gilteritinib in Rat Plasma and Application to a Drug-Drug Interaction Study.

BACKGROUND: Gilteritinib, a novel, potent FLT3/AXL inhibitor, was recently approved in Japan and USA for the treatment of adult patients who have relapsed or refractory acute myeloid leukemia (AML) with a FLT3 mutation. PURPOSE AND METHODS: In this study, we aimed to develop and validate a sensitive and simple ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the quantification of gilteritinib in plasma and to investigate whether CYP3A4 inhibitors (fluconazole and itraconazole) could influence the pharmacokinetics of gilteritinib from a drug-drug interaction study in rats. Sample preparation was done by a simple protein crash with acetonitrile containing the internal standard (IS) pirfenidone, followed by UPLC-MS/MS quantification. RESULTS: The assay was successfully validated in a 1-500 ng/mL calibration range for gilteritinib, where the lower limit of quantification (LLOQ) was set at 1 ng/mL. The intra-day and inter-day precisions for gilteritinib were less than 10.6%, and the accuracies were in the range of -14.5% to 11.1%. Recovery and matrix effect of the analyte and IS were acceptable, and the analyte was stable during the assay and storage in plasma samples. The validated UPLC-MS/MS method was successfully applied to a drug-drug interaction study between gilteritinib and CYP3A4 inhibitors (fluconazole and itraconazole) in rats. Itraconazole significantly increased the exposure of gilteritinib, and affected the pharmacokinetics of gilteritinib in rats, not fluconazole. CONCLUSION: A further clinical study should be conducted to investigate the effect of itraconazole on the metabolism of gilteritinib in subjects.

First-in-human, phase I single-ascending-dose study of the safety, pharmacokinetics, and relative bioavailability of selatinib, a dual EGFR-ErbB2 inhibitor in healthy subjects.

We assessed the pharmacokinetics and safety of a single oral administration of selatinib to healthy Chinese subjects and evaluated the potential bioavailability advantage of selatinib relative to lapatinib. Healthy subjects aged 18-40 years were enrolled in this two-part study: Part 1, a single ascending dose (50-500 mg), randomized, double-blind, placebo-control study with 64 subjects; and Part 2, an open-label, positive control, randomized, three-treatment, three-period, three-sequence crossover design study, with 6 subjects administered a single 500-mg dose of selatinib tablets (A), selatinib suspension (B), or lapatinib tablets C) per cycle. In part 1, selatinib was well-tolerated up to the planned maximum dose of 500 mg; thus the maximum tolerated dose was not attained. Twenty-two adverse events were observed in 19 (36.5%) of the 52 subjects administered the test drug. The most common drug-related adverse event was diarrhea. The mean selatinib peak plasma concentration was 69.4-494 ng/mL, which was achieved in a median peak time of 3.5-4.5 h, with a mean elimination half-life between 13.8 and 15.8 h. In Part 2, A and B showed similar bioavailability. Plasma exposure to the active drug (selatinib plus the metabolite, lapatinib) after A intake was more than two-fold higher than that of the same dose of C. In the dose range of 50-500 mg, selatinib was safe and well-tolerated by healthy Chinese subjects, and it conformed with linear pharmacokinetics. Active exposure to selatinib was much greater than that to lapatinib, supporting its development as an adjuvant for anticancer treatment.

Plasma screening for the T790M mutation of EGFR and phase 2 study of osimertinib efficacy in plasma T790M-positive non-small cell lung cancer: West Japan Oncology Group 8815L/LPS study.

BACKGROUND: Liquid biopsy allows the identification of patients whose tumors harbor specific mutations in a minimally invasive manner. No prospective data have been available for the efficacy of osimertinib in patients with non-small cell lung cancer (NSCLC) who develop resistance to first- or second-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) and who test positive for the TKI resistance-conferring T790M mutation of EGFR by liquid biopsy. Therefore, a phase 2 study was conducted to assess the efficacy and safety of osimertinib in such patients. METHODS: Eligible patients had advanced or recurrent NSCLC with known TKI-sensitizing mutations of EGFR, had documented disease progression after treatment with at least 1 first- or second-generation EGFR TKI, and were positive for the T790M mutation in plasma according to the Cobas EGFR Mutation Test v2 (Roche Diagnostics) or droplet digital polymerase chain reaction analysis. Patients were treated with osimertinib (80 mg/d) until disease progression. The primary endpoint was the overall response rate (ORR) in patients positive for T790M in plasma by the Cobas assay. RESULTS: Between June 2016 and November 2017, 276 patients were screened for their T790M status with a liquid biopsy. Seventy-four patients were positive for T790M in plasma, and 53 of these individuals were enrolled in the study. The ORR for evaluable patients positive for T790M in plasma by the Cobas assay (n = 49) was 55.1% (95% confidence interval [CI], 40.2%-69.3%). The median progression-free survival for all evaluable patients (n = 52) was 8.3 months (95% CI, 6.9-12.6 months). CONCLUSIONS: The results demonstrate the utility of liquid biopsy for the detection of T790M with the Cobas EGFR Mutation Test v2. Plasma genotyping with this assay is informative for treatment selection in clinical practice when tumor sampling is not feasible.

Plasma pharmacokinetic and metabolism of [18F]THK-5317 are dependent on sex.

INTRODUCTION: Tau deposition is one of the hallmarks of Alzheimer's disease (AD) and can be visualized and quantified using [18F]THK-5317 together with kinetic modeling. To determine the feasibility of this approach, we measured blood/plasma pharmacokinetics and radiotracer metabolism in female and male rats. METHODS: Female and male rats (n = 11-12) were cannulated via the femoral artery for continuous blood sampling. Blood sampling was performed at regular intervals after intravenous injection of [18F]THK-5317. After collection of the last blood sample, animals were sacrificed, and organs were excised. Blood from minute 5, 20 and 60 was centrifuged to obtain plasma. Radiolabeled metabolites in plasma, brain, liver and urine were analyzed by radio-thin-layer chromatography (radio-TLC). RESULTS: Plasma pharmacokinetics and metabolism were significantly different between female and male rats. [18F]THK-5317 plasma clearance was faster in female (0.66 ± 0.08 mL/h/kg BW) than in male (0.52 ± 0.11 mL/h/kg BW) rats (p = .005). The percentage of unmetabolized parent was significantly different between both sexes at 20 min and 60 min p.i. In the liver, a 1.6-fold higher radioactivity concentration was found in male versus female animals and in addition also the percentage of unmetabolized parent was different. CONCLUSION: Our results show pronounced sex differences in blood/plasma pharmacokinetics and metabolism of [18F]THK-5317 in rats. Female animals showed a faster plasma clearance compared to males. These results underline the importance of investigating both sexes and also support the notion that individual input functions or sex-specific population-based input functions are needed for kinetic modeling analyses. ADVANCES IN KNOWLEDGE: First preclinical study in rats showing pronounced sex differences in blood/plasma pharmacokinetics and metabolism of [18F]THK-5317. IMPLICATIONS FOR PATIENT CARE: Sex-specific differences might also be present in humans and thus clinical trials should have adequate sample size to account for effects in men and women separately.

Liquid chromatography-tandem mass spectrometric method for the quantification of eliglustat in rat plasma and the application in a pre-clinical study.

Eliglustat is an oral substrate reduction therapy drug and has been approved as a first-line treatment for adults with Gaucher disease type 1 (GD 1). In the present study, we aimed to develop and establish an accurate and simple ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the measurement of eliglustat concentration in rat plasma. The goal of chromatographic separation of eliglustat and the internal standard (bosutinib) was finished on an Acquity BEH C18 (2.1 mm × 50 mm, 1.7 µm) column. Acetonitrile and 0.1% formic acid in water were employed as the mobile phase in a mode of gradient elution with the 0.40 mL/min flow rate. The detection was carried out on a XEVO TQ-S triple quadrupole tandem mass spectrometer coupled with electrospray ionization (ESI) interface in the positive-ion mode. Multiple reaction monitoring (MRM) was used to monitor the precursor-to-product ion transitions of m/z 405.4 → 84.1 for eliglustat and m/z 530.2 → 141.2 for bosutinib (IS), respectively. It was found that the linearity of the method in the range of 1-500 ng/mL was good for eliglustat. The values of intra- and inter-day accuracy and precision were all within the acceptance limits, and no matrix effect was found in this method. The current developed method was further performed to support in vivo pharmacokinetic study of eliglustat after oral treatment with 10 mg/kg eliglustat to rats.

Bioanalysis of EGFRm inhibitor osimertinib, and its glutathione cycle- and desmethyl metabolites by liquid chromatography-tandem mass spectrometry.

Osimertinib is a "third-generation'' oral, irreversible, tyrosine kinase inhibitor. It is used in the treatment of non-small cellular lung carcinoma and spares wild-type EGFR. Due to its reactive nature, osimertinib is, in addition to oxidative routes, metabolized through GSH coupling and subsequent further metabolism of these conjugates. The extent of the non-oxidative metabolism of osimertinib is unknown, and methods to quantify this metabolic route have not been reported yet. To gain insight into this metabolic route, a sensitive bioanalytical assay was developed for osimertinib, the active desmethyl metabolite AZ5104, and the thio-metabolites osimertinibs glutathione, cysteinylglycine, and cysteine conjugates was developed. The ease of synthesis of these metabolites was a key-part in the development of this assay. This was done through simple one-step synthesis and subsequent LC-purification. The compounds were characterized by NMR and high-resolution mass spectrometry. Sample preparation was done by a simple protein crash with acetonitrile containing the stable isotopically labeled internal standards for osimertinib and the thio-metabolites, partial evaporation of solvents, and reconstitution in eluent, followed by UHPLC-MS/MS quantification. The assay was successfully validated in a 2-2000 nM calibration range for all compounds except the glutathione metabolite, where the LLOQ was set at 6 nM due to low accuracy at 2 nM. Limited stability was observed for osimertinib, AZ5104, and the glutathione metabolite. The clinical applicability of the assay was demonstrated in samples of patients treated with 80 mg osimertinib once daily, containing all investigated compounds at detectable and quantifiable levels.

UPLC-MS/MS method for the determination of talazoparib in rat plasma and its pharmacokinetic study.

In the present study, an accurate and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the determination of plasma talazoparib concentration in rats was developed and established. The purpose of chromatographic separation of talazoparib and the internal standard (bosutinib) was achieved on an Acquity BEH C18 (2.1 mm × 50 mm, 1.7 µm) column with a flow rate of 0.40 mL/min, using a gradient elution with acetonitrile and 0.1% formic acid in water as the mobile phase. The detection was performed on a XEVO TQ-S triple quadrupole tandem mass spectrometer coupled with electrospray ionization interface under positive-ion multiple reaction monitoring (MRM) mode with the precursor-to-product ion transitions of m/z 381.3 → 285.2 for talazoparib and m/z 530.2 → 141.2 for bosutinib (IS), respectively. The method was linear over the range of 0.5-200 ng/mL for talazoparib. The accuracies and precisions of intra- and inter-day were all within the acceptance limits, and no matrix effect was observed in this method. The validated method was further employed to a pharmacokinetic study of talazoparib after oral treatment with 0.2 mg/kg talazoparib to rats.

Validation of an analytical method using HPLC-MS/MS to quantify osimertinib in human plasma and supplementary stability results.

A new method for quantification of osimertinib (OSIM) in human plasma using a high-performance liquid chromatography-tandem mass spectrometry method was developed and validated. Methanol was used for protein precipitation and pazopanib as internal standard. Separation was performed on a HyPURITY®C18 analytical column (50 × 2.1 mm; 3 µm) using a gradient elution of ammonium acetate in water and ammonium acetate in methanol, both acidified with formic acid 0.1%. Detection and quantification of OSIM and pazopanib was performed using a triple quadruple mass spectrometer after electrospray ionization. This method led to robust results, as the selectivity, carryover, precision and accuracy all met pre-specified requirements. OSIM was stable in human serum when stored at -80°C. Reduced stability was found when stored at 2-4°C or room temperature. Degradation of OSIM slowed down in EDTA-plasma and acidified human serum. The limited stability of OSIM at room temperature should be considered for transport and sample preparation. Plasma samples should be frozen as soon as possible and sample preparation should be performed on dry-ice. In the future, EDTA-plasma and sample acidification may be used to improve OSIM stability at room temperature. However, more research and validation of such an approach are required.

Novel high-performance liquid chromatography-tandem mass spectrometry method for simultaneous quantification of BCR-ABL and Bruton's tyrosine kinase inhibitors and their three active metabolites in human plasma.

Therapeutic drug monitoring is important in patients taking BCR-ABL and Bruton's tyrosine kinase inhibitors (TKIs). Some TKI active metabolites with long elimination half-lives, such as dihydrodiol ibrutinib (DHI), N-desmethyl imatinib (N-DI), and N-desmethyl ponatinib (N-DP), have been characterized, indicating that these active metabolites should be monitored along with the parent compounds. However, there are currently no methods for the simultaneous quantification of BCR-ABL and Bruton's TKIs and their three active metabolites. The present study aimed to develop and validate a method for the simultaneous quantification of nine pharmacologically active compounds (bosutinib, dasatinib, DHI, ibrutinib, imatinib, N-DI, N-DP, nilotinib, and ponatinib) using high-performance liquid chromatography-tandem mass spectrometry. A 150-µL sample of plasma was analyzed after purification with supported liquid extraction. The method has a run time of 7 min and was successfully validated over the following calibration ranges: 0.25-75 ng/mL for N-DP, 0.5-150 ng/mL for dasatinib and ponatinib, 10-3000 ng/mL for imatinib and nilotinib, and 1-300 ng/mL for the other analytes. Stability of the analytes after short- and long-term storage in the presence of plasma matrix was examined, and all analytes were found to be stable under all tested conditions. The recovery was ≥83%, and the relative standard deviation of internal-standard normalized matrix effects ranged from 3.9 to 13.9%. Dilution integrity up to 4-fold was ensured. The applicability of the method for all analytes was demonstrated using patient samples.

Development and validation of a liquid chromatography-tandem mass spectrometry assay for nine oral anticancer drugs in human plasma.

A liquid chromatography-tandem mass spectrometry assay was developed and validated for the nine oral anticancer agents alectinib, cobimetinib, lenvatinib, nintedanib, osimertinib, palbociclib, ribociclib, vismodegib and vorinostat in order to support therapeutic drug monitoring (TDM). The assay was based on reversed-phase chromatography coupled with tandem mass spectrometry operating in the positive ion mode. The assay was validated based on the guidelines on bioanalytical methods by the US Food and Drug Administration and European Medicines Agency. The method was validated over a linear range of 10-200 ng/mL for alectinib, lenvatinib, nintedanib and vismodegib; 50-1000 ng/mL for cobimetinib and palbociclib; 100-2000 ng/mL for osimertinib; 5.00-100 ng/mL for ribociclib; 25-500 ng/mL for vorinostat. Intra-assay and inter-assay bias was within ±20% for all analytes at the lower limit of quantification and within ±15% at remaining concentrations. Stability experiments showed that osimertinib is unstable in the biomatrix and should be shipped on dry-ice and stored at -20 °C until analysis. All other compounds were stable in the biomatrix. The described TDM method was successfully validated and applied for TDM in patients treated with these KIs.

Determination of osimertinib in human plasma, urine and cerebrospinal fluid.

Aim: Osimertinib (Tagrisso, AZD9291) has been approved for the treatment of patients with metastatic EGFRm T790M non-small-cell lung cancer. Results: Rapid and sensitive LC-MC/MS methods were developed for osimertinib and its metabolites, AZ13597550 and AZ13575104, in human plasma (low- and high-range), urine and cerebrospinal fluid. We discuss the challenges of these multi-analyte and multiple matrix assays. The methods have been successfully validated and used for the analysis of over 20,000 clinical samples, with successful incurred sample reproducibility. Conclusion: The assays have been shown to be selective, accurate and robust, providing high-throughput analysis during the clinical development of osimertinib.