Simultaneous quantification of abemaciclib and its active metabolites in human and mouse plasma by UHPLC-MS/MS

Assay for the quantification of abemaciclib, its metabolites, and olaparib in human plasma by liquid chromatography-tandem mass spectrometry

An isotope-dilution bioanalytical assay for abemaciclib and its metabolites in combination with olaparib was developed and validated in human plasma K2 EDTA. For the quantitative assay, human plasma samples (or human plasma QC samples) were spiked with internal standard solution before a simple protein precipitation with methanol. The extract was injected onto a liquid chromatography-tandem mass spectrometry (LC-MS/MS) instrument where it was chromatographically separated by a polar end-capped reversed phase column and guard using gradient elution with water and methanol both modified with 0.2 % formic acid (v/v) as the mobile phases. The analytes and internal standards were measured by heated electrospray ionization (HESI) in positive polarity using selected reaction monitoring (SRM) on a triple quadrupole mass spectrometer. The assay was validated for linear ranges as follows: 0.4 - 1000 nM abemaciclib, 0.35 - 1000 nM M2 and M18, 0.5 - 1000 nM M20, and 0.75 - 1000 nM olaparib. The inter-day or between day precision for the quality controls (n = 18) was < 13 % and the accuracy was ± 12 %, for all analytes, including the lower limit of quantification (LLOQ). The intra-day or within day precision for the quality controls (n = 6) was ≤ 11 % and the accuracy was ± 12 % for low, mid, and high and < 19 % at LLOQ. The recovery in human plasma was determined to be between 92 % and 102 % for all analytes spanning the linear range. The validated, bioanalytical quantitative assay was designed to measure abemaciclib, its metabolites, and olaparib for pharmacokinetic evaluation of patients in clinical trials for breast, brain, and ovarian cancers.

Quantification of Letrozole, Palbociclib, Ribociclib, Abemaciclib, and Metabolites in Volumetric Dried Blood Spots: Development and Validation of an LC-MS/MS Method for Therapeutic Drug Monitoring

Therapeutic drug monitoring (TDM) may be beneficial for cyclin-dependent kinase 4/6 inhibitors (CDK4/6is), such as palbociclib, ribociclib, and abemaciclib, due to established exposure-toxicity relationships and the potential for monitoring treatment adherence. Developing a method for quantifying CDK4/6is, abemaciclib metabolites (M2, M20), and letrozole in dried blood spots (DBS) could be useful to enhance the feasibility of TDM. Thus, an optimized LC-MS/MS method was developed using the HemaXis DB10 device for volumetric (10 µL) DBS collection. Chromatographic separation was achieved using a reversed-phase XBridge BEH C18 column. Detection was performed with a triple quadrupole mass spectrometer, utilizing ESI source switching between negative and positive ionization modes and multiple reaction monitoring acquisition. Analytical validation followed FDA, EMA, and IATDMCT guidelines, demonstrating high selectivity, adequate sensitivity (LLOQ S/N ≥ 30), and linearity (r ≥ 0.997). Accuracy and precision met acceptance criteria (between-run: accuracy 95-106%, CV ≤ 10.6%). Haematocrit independence was confirmed (22-55%),with high recovery rates (81-93%) and minimal matrix effects (ME 0.9-1.1%). The stability of analytes under home-sampling conditions was also verified. Clinical validation supports DBS-based TDM as feasible, with conversion models developed for estimating plasma concentrations (the reference for TDM target values) of letrozole, abemaciclib, and its metabolites. Preliminary data for palbociclib and ribociclib are also presented.

Abemaciclib pharmacology and interactions in the treatment of HR+/HER2- breast cancer: a critical review

Abemaciclib (ABE) in combination with endocrine therapy represents the mainstay treatment for either endocrine-resistant metastatic or high-risk early-stage HR+/HER2- breast cancer patients. Hence, an adequate knowledge of this agent pharmacodynamic, pharmacokinetic, and of its drug-drug interactions (DDIs) is crucial for an optimal patients management. Additionally, ABE interference with food and complementary/alternative medicines should be taken into account in the clinical practice. Several online tools allow to freely check DDIs and can be easily consulted before prescribing ABE. According to one of this instruments, ABE display the lowest number of interactions among the available cyclin-dependent kinase 4/6 inhibitors. Still, clinicians should be aware that online tools cannot replace the technical datasheet of the drug as well as a comprehensive clinical assessment for each patient. Here we critically review the main pharmacological features of ABE, then focusing on its potential interactions with drugs, food, and alternative medicine, in order to provide a guide for its optimal use in the treatment of HR+/HER2- breast cancer patients.

Dispersive liquid-liquid microextraction followed by sweeping micellar electrokinetic chromatography-tandem mass spectrometry for determination of six breast cancer drugs in human plasma

Herein, we have developed a novel method of aqueous-sample dispersive liquid-liquid microextraction (AqS-DLLME) followed by sweeping micellar electrokinetic chromatography-tandem mass spectrometry (MEKC-MS/MS) for simultaneous determination of breast cancer drugs letrozole, anastrozole, palbociclib, ribociclib, abemaciclib, and fulvestrant in human plasma. Coupling of MEKC to MS was possible due to the use of ammonium perfluorooctanoate (APFO) as a volatile surfactant. The MEKC and MS conditions were optimized to achieve a fast, sensitive, selective, and green analysis enabling full separation of the analytes within 16 min. Electrophoretic buffer was 125 mM APFO at apparent pH 10.5 in 32 % MeOH, while sheath liquid was 70 % MeOH with 0.2 % formic acid, delivered at 10 µL/min. Excellent extraction recoveries from plasma ranging from 89.4 to 104.9 % were obtained with a combination of protein precipitation and DLLME. The developed method was validated according to the ICH guidelines. Remarkable selectivity, accuracy (bias < 6.7 %), precision (RSD < 15.8 %), and stability (bias < 10.4 %) with insignificant matrix effect (RSD < 14.0 %) and no carry-over were obtained over a wide range of concentrations. Linearity with inter-day slope RSD lower than 8.7 % was demonstrated. With this method, very low concentrations could be detected after the injection of only 68.7 nL of the sample. The method was applied to plasma samples from six women currently receiving breast cancer treatment. Determined concentrations of the drugs of interest agreed with concentrations found in clinical studies, thus proving the suitability of the developed method for therapeutic drug monitoring as a superior alternative to published LC-MS methods.

Therapeutic drug monitoring in breast cancer therapy - LC-MS/MS method for quantification of the CDK4/6 inhibitors abemaciclib, palbociclib, ribociclib, and major metabolites abemaciclib M20 and M2 in human serum

The cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors palbociclib, ribociclib, and abemaciclib were approved by the U.S. Food and Drug Administration (FDA) and European Medicine Agency for the treatment of breast cancer between 2015 and 2018. Oral tumor therapeutics extend the options for cancer therapy, but also challenge physicians and patients. The aim of the present work was to establish a semi-automated liquid-chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of abemaciclib, its active metabolites abemaciclib M20 and M2, palbociclib, and ribociclib in human serum. Detuning of ribociclib enabled the development of a simultaneous quantification method for abemaciclib, M20, M2, palbociclib, and ribociclib in the respective relevant concentration ranges based on semi-automated sample preparation with isotope dilution LC-MS/MS. The method was validated according to the guidance of the FDA. The LC-MS/MS method was successfully validated according to FDA and showed inaccuracies ≤ 10.7% and imprecisions ≤ 8.51%. Linearity was given from 20 to 800 ng/mL for abemaciclib, 15-600 ng/mL for M20, 10-400 ng/mL for M2 and palbociclib, and 100-4000 ng/mL for ribociclib. Normalized matrix factors and process efficiency showed no significant matrix effects regardless of the analytes. To demonstrate the applicability of the method, authentic samples were also analyzed. This novel semi-automated LC-MS/MS method covering all previously approved CDK4/6 inhibitors as well as the similarly pharmacologically active metabolites in human serum simultaneously was developed for potential future use in routine analysis in order to improve personalized therapy, patient safety, and treatment success.

Development of a SPE-LC-MS Method for the Quantitation of Palbociclib and Abemaciclib in Human Plasma

Palbociclib and abemaciclib are two cyclin-dependent kinases 4 and 6 used for breast cancer treatment. Levels of these medicines present a significant interindividual variability, so monitoring those concentrations might be necessary in therapy. Most of the methods presented so far in the literature use simple protein precipitation of plasma proteins as sample preparation method followed by direct injection of the supernatant into the LC instrument, preceded or not by a simple filtration step. Within that approach, the probability of injecting proteins in the chromatographic system is increased. With the purpose of obtaining a cleaner extract of the drugs, we developed and validated a simple and accurate LC-MS method for determining palbociclib and abemaciclib in human plasma. Solid phase extraction (SPE) using Oasis PRiME HLB^® cartridges was used for plasma sample preparation. The method provided clean extracts with a recovery extraction higher than 85% for both compounds. Separation was achieved by high-performance liquid chromatography (HPLC), using a C18 (4.6 × 50 mm) column, with a gradient elution of ammonium acetate/acetic acid-acetonitrile as the mobile phase. Detection was performed by mass spectrometry (MS) in single ion recording (SIR) mode. Intra-day and inter-day precision data for both analytes were 3.8-7.2% and 3.6-7.4%, respectively. Calibration curves were both linear between 2 and 400 ng/mL with a correlation coefficient higher than 0.998. The LC-MS method can be used to quantify the drugs in human plasma in routine analysis. The method proved to be useful in determining real plasma levels in patients involved in cancer therapy. Drug concentrations were determined in a 10 min run-time, including re-equilibration of the column.

Pharmacokinetic study on the co-administration of abemaciclib and astragaloside IV in rats

CONTEXT

The co-administration of abemaciclib and astragaloside IV might occur in the treatment of breast cancer.

OBJECTIVE

This study evaluates the interaction between abemaciclib and astragaloside IV in rats and describes the potential mechanism.

MATERIALS AND METHODS

Male Sprague Dawley rats were randomly divided into four groups: single dose of abemaciclib (control), abemaciclib + 50 mg/kg/d astragaloside IV, abemaciclib + 100 mg/kg/d astragaloside IV, and abemaciclib + 150 mg/kg/d astragaloside IV. Abemaciclib and astragaloside IV were orally administrated, and astragaloside IV was pre-administrated for 7 d in the co-administrated groups. The pharmacokinetics and transport of abemaciclib were assessed in the absence or presence of astragaloside IV. In mechanism, the activity of CYP3A4 was estimated in human liver microsomes in the presence of astragaloside IV.

RESULTS

Astragaloside IV significantly increased the C_max (from 991.5 ± 116.99 up to 2308.5 ± 55.29 μg/L) and AUC (from 24.49 ± 2.86 up to 66.14 ± 1.17 μg/mL × h) and prolonged the t_1/2 (from 19.85 ± 4.65 up to 66.17 ± 28.73 h) of abemaciclib, and the effect was enhanced with the increasing astragaloside IV concentration. Astragaloside IV also suppressed the transport of abemaciclib with the efflux ratio decreasing to 1.35. Astragaloside IV suppressed the activity of CYP3A4 with an IC₅₀ value of 21.78 μM.

DISCUSSION AND CONCLUSIONS

The co-administration of abemaciclib and astragaloside IV induced the increasing systemic exposure of abemaciclib through the inhibition of CYP3A4. Further clinical validations could be carried out according to the study design of the present investigation.

Detection of abemaciclib, an anti-breast cancer agent, using a new electrochemical DNA biosensor

Detection of DNA molecules and possible chemotherapy-induced changes in its structure has been the goal of researchers using rapid, sensitive and inexpensive approaches. Therefore, the aim of this study was to fabricate a new electrochemical DNA biosensor using pencil graphite electrodes modified with polypyrrole/Ce doped hexagonal nickel oxide nanodisks or PP/Ce-doped H-NiO-ND composites for determination of Abemaciclib (AMC) and ds-DNA molecules. The DNA biosensor was prepared by immobilizing ds-DNA on the surface of PP/Ce-doped H-NiO-ND/PGE. Differential pulse voltammetry (DPV) was used to electrochemically detect AMC. The results elucidate the extremely high sensitivity of the ds-DNA/PP/Ce-doped H-NiO-ND/PGE biosensor to AMC, with a narrow detection limit of 2.7 nM and a lengthy linear range of 0.01–600.0 μM. The admirable performance of as-fabricated biosensor could be related to the active reaction sites and the unique electrochemical response related to the nanocomposites by enhancing ds-DNA stabilization and accelerating electron transfer on the surface of electrode.

"A new LC-MS/MS method for the simultaneous quantification of abemaciclib, its main active metabolites M2 and M20, and letrozole for therapeutic drug monitoring"

Abemaciclib (ABEMA) is the last CDKi approved for the treatment of breast cancer. Adverse reactions to this drug are not experienced in the same manner by the entire patient population but in case of severe toxicity dose reductions and therapy discontinuation are required, suggesting that a TDM-guided treatment could be beneficial for these patients. ABEMA is extensively metabolized by the liver. The most abundant active metabolites are M2 and M20. This CDKi is administered together with anti-estrogen drugs, such as letrozole (LETRO). The aim of this work was to develop and validate a LC-MS/MS method for the simultaneous quantification of ABEMA, M2, M20, and LETRO. The chromatographic separation of the analytes was obtained using a SIL-20AC XR auto-sampler coupled to LC-20AD UFLC Prominence XR pumps (Shimadzu, Tokyo, Japan). The chromatographic column employed was an XTerra MS C18, (3,5 µm, 125 Å, 50x2.1 mm) coupled with a Security Guard Cartridge (MS C18, 125 Å, 3.9x5 mm) provided by Waters. Detection was performed by an API 4000 QTrap (SCIEX) mass spectrometer. The presented analytical method was fully validated according to EMA and FDA guidelines on bioanalytical method validation. Linearity was confirmed on 10 independent tests (R² within 0.997-1.000) over the concentration ranges of 40-800 ng/mL for ABEMA, 10-200 ng/mL for M2 and M20, 20-400 ng/mL for LETRO. The method was applied to analyze plasma samples from patients enrolled in a clinical trial, collected at C_min. Incurred sample reanalysis was performed on a set of 30 samples, confirming the reproducibility of the analytical method.

An UHPLC-MS/MS method for quantification of the CDK4/6 inhibitor abemaciclib in human serum

BACKGROUND

Abemaciclib is a new oral targeted treatment option for patients with advanced breast cancer. The emerging field of oral antitumor therapeutics presents challenges for both patients and healthcare teams; non-adherence and high inter-individual pharmacokinetic variability can influence response rates.

METHODS

For monitoring abemaciclib in human sera, a rapid novel ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed and fully validated. Sample preparation was based on a protein precipitation step followed by on-line solid phase extraction. Chromatographic separation was achieved using a biphenyl column and the isotope labeled standard abemaciclib-d8 was used for quantification.

RESULTS

The method showed linearity over a wide calibration range from 20.0 to 2500 ng/mL. With accuracies and precisions of ≤13.9% and ≤4.42%, respectively, the validation results were within the criteria of acceptance. The fitness of the method was tested by monitoring abemaciclib levels under compassionate use for a single individual.

CONCLUSIONS

The novelty of the presented two dimensional isotope dilution UHPLC-MS/MS method is in the semi-automated sample preparation, which results in negligible matrix effects, thereby allowing the introduction of abemaciclib into robust routine therapeutic drug monitoring (TDM). This method provides an efficient tool to verify the usefulness of personalized anticancer therapy in clinical practice.

ABCB1 and ABCG2 limit brain penetration and, together with CYP3A4, total plasma exposure of abemaciclib and its active metabolites

Abemaciclib is the third cyclin-dependent kinase (CDK) 4/6 inhibitor approved for the treatment of breast cancer and currently under investigation for other malignancies, including brain cancer. Primarily CYP3A4 metabolizes abemaciclib, forming three active metabolites (M2, M20 and M18) that are likely relevant for abemaciclib efficacy and toxicity. We investigated the impact of ABCB1 (P-gp), ABCG2 (BCRP) and CYP3A on the pharmacokinetics and tissue distribution of abemaciclib and its metabolites using genetically modified mice. In vitro, abemaciclib was efficiently transported by hABCB1 and mAbcg2, and slightly by hABCG2, but the active metabolites were transported even better. Upon oral administration of 10mg/kg abemaciclib, absence of Abcg2 and especially Abcb1a/1b significantly increased the plasma AUC_0-24h and C_max of M2 and M18. Furthermore, the relative brain penetration of abemaciclib, M2 and M20 was dramatically increased by 25-, 4- and 60-fold, respectively, in Abcb1a/1b;Abcg2^-/- mice, and to a lesser extent in single Abcb1a/1b- or Abcg2-deficient mice. The recovery of all active compounds in the small intestine content was profoundly reduced in Abcb1a/1b;Abcg2^-/- mice, with smaller effects in single Abcb1a/1b^-/- and Abcg2^-/- mice. Our results indicate that Abcb1a/1b and Abcg2 cooperatively and profoundly limit the brain penetration of abemaciclib and its active metabolites, and likely also participate in their hepatobiliary or direct intestinal elimination. Moreover, transgenic human CYP3A4 drastically reduced the abemaciclib plasma AUC_0-24h and C_max by 7.5- and 5.6-fold, respectively, relative to Cyp3a^-/- mice. These insights may help to optimize the clinical development of abemaciclib, especially for the treatment of brain malignancies.