Pharmacokinetic Studies Research Articles

Highly sensitive liquid chromatography-mass spectrometry method for the quantitative analysis of mometasone furoate in human plasma: Method validation and application to clinical pharmacokinetic studies.

We report the development and the validation of a sensitive liquid chromatography-mass spectrometry (LC-MS/MS) method for mometasone furoate (MF) analysis in human plasma. Plasma samples were processed through liquid-liquid extraction and analyzed using LC-MS/MS operating in positive mode using multiple reaction monitoring of transitions m/z 520.9→ 355.0 and m/z 525.8→ 355.0 for MF and the internal standard (IS), respectively. Separation was achieved at 1.0mL/min on a C18 column using a gradient elution of mobile phase of 0.05% ammonia in water (phase A) and acetonitrile (phase B). The assay range was 0.250-100 pg/mL and proved to be accurate and precise MF. Normalized recoveries were consistent and reproducible with a coefficient of variation (CV%) value of 6.0. The CV (%) of the IS normalized matrix factor was not observed in normal, lipemic, and hemolyzed plasmas. Dilutions of 1:10 were accurately quantified. A cycle of three freeze and thaw and stabilities at room temperature and on the autosampler were demonstrated. In addition, MF in the presence of indacaterol and glycopyrronium was proven to be stable at -70°C for at least 157 days. The present method was successfully applied to quantify MF in patients receiving MF, indacaterol, and glycopyrronium as a fixed-dose combination.

Pharmacokinetic Study of Tilianin After Oral Administration in Wistar Rats by HPLC

Pharmacokinetic Study of Tilianin After Oral Administration in Wistar Rats by HPLC

Method development and validation for the estimation of gedatolisib in mouse plasma by tandem mass spectrometry and its application to pharmacokinetics studies.

A simple and a sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of gedatolisib in mouse plasma. The extraction technique involved a simple precipitation method to extract gedatolisib and idelalisib (internal standard) from mouse plasma. A clean chromatographic separation of gedatolisib and the internal standard was achieved on an Atlantis dC18 column using an isocratic mobile phase (10mm ammonium formate and acetonitrile; 30:70% v/v, both supplemented with 0.1% formic acid) delivered at a flow rate of 0.7ml/min. The total run time was 2.0min, and gedatolisib and idelalisib were eluted at 0.80 and 0.95 min, respectively. Gedatolisib was monitored at m/z 616.40 → 488.20 and idelalisib at 416.05 → 176.10. All the required parameters for the method validation were performed as per US Food and Drug Administration guidelines, and the results were within the acceptance criteria. The method was accurate and proved to be precise at a linearity range of 1.33-2667 ng/ml. The accuracy for gedatolisib in mouse plasma was in the ranges 0.99-1.06% (intra-day) and 0.96-1.04% (inter-day). Gedatolisib appeared to be stable in a series of stability conditions. Gedatolisib showed a good intravenous profile when administered through a solution formulation.

Cefadroxil and cephalexin pharmacokinetics and pharmacodynamics in children with musculoskeletal infections.

Cephalexin, a first-generation cephalosporin, is the first-line oral therapy for children with musculoskeletal infections due to methicillin-susceptible Staphylococcus aureus (MSSA). Cefadroxil, a similar first-generation cephalosporin, is an attractive alternative to cephalexin given its longer half-life. In this study, we describe the comparative pharmacokinetics (PK) and pharmacodynamics (PD) of cephalexin and cefadroxil in children with musculoskeletal infections. Children aged 6 months to 18 years with a musculoskeletal infection were enrolled in a prospective, open-label, crossover PK study and given single oral doses of cefadroxil (50-75 mg/kg up to 2,000 mg) and cephalexin (50 mg/kg up to 1,375 mg). Population PK models were developed and used for dosing simulations. Our primary PD target was the achievement of free antibiotic concentrations above the minimum inhibitory concentration (fT >MIC) for 40% of the day for MICs ≤ 4 mg/L. PK of cephalexin (n = 15) and cefadroxil (n = 14) were best described using a one-compartment, first-order absorption model, with a lag time component for cefadroxil. PK parameters were notable for cefadroxil's longer half-life (1.61 h) than cephalexin's (1.10 h). For pediatric weight bands, our primary PD target was achieved by cephalexin 25 mg/kg/dose, maximum 750 mg/dose, administered three times daily and cefadroxil 40 mg/kg/dose, maximum 1,500 mg/dose, administered twice daily. More aggressive dosing was required to achieve higher PD targets. Among children with musculoskeletal infections, oral cephalexin and cefadroxil achieved PD targets for efficacy against MSSA. Given less frequent dosing, twice-daily cefadroxil should be further considered as an alternative to cephalexin for oral step-down therapy for serious infections due to MSSA.

Iodine-induced synthetic method and pharmacokinetic study of cis- and trans-crocetin.

This experiment aimed to obtain the relatively rare cis-crocetin isomer from natural plants, which predominantly exist in the more stable all-trans configuration. This was achieved through iodine-induced isomerization, followed by purification and structural identification. The study also aimed to compare the pharmacokinetic differences between cis- and trans-crocetin in vivo. Trans-crocetin of high purity was extracted by hydrolysis from gardenia yellow pigment. Cis-crocetin was then synthesized through an optimized electrophilic addition reaction induced by elemental iodine, and subsequently separated and purified via silica gel column chromatography. Structural identification of cis-crocetin was determined using IR, UV, and NMR techniques. In vivo pharmacokinetic studies were conducted for both cis- and trans-crocetin. In addition to this, we have conducted a comparative study on the in vivo anti-hypoxic activity of trans- and cis-crocetin. Under the selected reaction conditions using DMF as the solvent, with a concentration of 2.5mg/mL for both trans-crocetin and the iodine solution, and adjusting the illumination time according to the amount of trans-crocetin, the rate of iodine-induced isomerization was the fastest. Cis-crocetin was successfully obtained and, after purification, its structure was identified and found to be consistent with reported data. Cis-crocetin exhibited a faster absorption rate and higher bioavailability, and despite its shorter half-life, it could partially convert to trans-crocetin in the body, thereby extending the duration of the drug's action within the body to some extent. This study accomplished the successful preparation and structural identification of cis-crocetin. Additionally, through pharmacokinetic studies, it uncovered notable variations in bioavailability between cis- and trans-crocetin. These findings serve as a solid scientific foundation for future functional research and practical applications in this field.

Impact of covariate model building methods on their clinical relevance evaluation in population pharmacokinetic analyses: comparison of the full model, stepwise covariate model (SCM) and SCM+ approaches.

Covariate analysis in population pharmacokinetics is key for adjusting doses for patients. The main objective of this work was to compare the adequacy of various modeling approaches on covariate clinical relevance decision-making. The full model, stepwise covariate model (SCM) and SCM+ PsN algorithms were compared in a clinical trial simulation of a 383-patient population pharmacokinetic study mixing rich and sparse designs. A one-compartment model with first-order absorption was used. A base model including a body weight effect on CL/F and V/F and a covariate model including 4 additional covariates-parameters relationships were simulated. As for forest plots, ratios between covariates at a specific value and that of a typical individual were calculated with their 90% confidence interval (CI90) using standard errors. Covariates on CL, V and KA were considered relevant if their CI90 fell completely outside the reference area [0.8-1.2]. All approaches provided unbiased covariate ratio estimates. For covariates with a simulated effect, the 3 approaches correctly identify their clinical relevance. However, significant covariates were missed in up to 15% of cases with SCM/SCM+. For covariate with no simulated effects, the full model mainly identified them as non-relevant or with insufficient information while SCM/SCM+ mainly did not select them. SCM/SCM+ assume that non-selected covariates are non-relevant when it could be due to insufficient information, whereas the full model does not make this assumption and is faster. This study must be extended to other methods and completed by a more complex high-dimensional simulation framework.

View on Metformin: Antidiabetic and Pleiotropic Effects, Pharmacokinetics, Side Effects, and Sex-Related Differences.

Metformin is a synthetic biguanide used as an antidiabetic drug in type 2 diabetes mellitus, achieved by studying the bioactive metabolites of Galega officinalis L. It is also used off-label for various other diseases, such as subclinical diabetes, obesity, polycystic ovary syndrome, etc. In addition, metformin is proposed as an add-on therapy for several conditions, including autoimmune diseases, neurodegenerative diseases, and cancer. Although metformin has been used for many decades, it is still the subject of many pharmacodynamic and pharmacokinetic studies in light of its extensive use. Metformin acts at the mitochondrial level by inhibiting the respiratory chain, thus increasing the AMP/ATP ratio and, subsequently, activating the AMP-activated protein kinase. However, several other mechanisms have been proposed, including binding to presenilin enhancer 2, increasing GLP1 release, and modification of microRNA expression. Regarding its pharmacokinetics, after oral administration, metformin is absorbed, distributed, and eliminated, mainly through the renal route, using transporters for cationic solutes, since it exists as an ionic molecule at physiological pH. In this review, particular consideration has been paid to literature data from the last 10 years, deepening the study of clinical trials inherent to new uses of metformin, the differences in effectiveness and safety observed between the sexes, and the unwanted side effects. For this last objective, metformin safety was also evaluated using both VigiBase and EudraVigilance, respectively, the WHO and European databases of the reported adverse drug reactions, to assess the extent of metformin side effects in real-life use.

Distribution of Bevacizumab into the Cerebrospinal Fluid of Children and Adolescents with Recurrent Brain Tumors.

To date, evidence has been lacking regarding bevacizumab pharmacokinetics in the cerebrospinal fluid (CSF). This study assessed the penetration of bevacizumab, as part of a metronomic antiangiogenic treatment regimen, into the CSF of children, adolescents, and young adults with recurrent brain tumors. Serum and CSF concentrations, malignant cells, and vascular endothelial growth factor A (VEGF-A) were analyzed in 12 patients (5-27 years) following 10 mg/kg bevacizumab intravenous biweekly administration (EudraCT number 2009-013024-23). A population pharmacokinetic model including body weight, albumin, and tumor type as influential factors was extended to quantify the CSF penetration of bevacizumab. Apart from in serum (minimum concentration/maximum concentration [Cmin/Cmax] 77.0-305/267-612 mg/L, median 144/417mg/L), bevacizumab could be quantified in the CSF (0.01-2.26mg/L, median 0.35 mg/L). The CSF/serum ratio was 0.16 and highly variable between patients. Malignant cells could be detected in CSF before initiation of treatment in five of 12 patients; after treatment, the CSF was cleared in all patients. VEGF-A was detected in three patients before treatment (mean ± SD: 20 ± 11 pg/mL), and was still measurable in one of these patients despite treatment (16 pg/mL). This pharmacokinetic pilot study indicated penetration of bevacizumab into the CSF in a population of children, adolescents, and young adults with recurrent brain tumors.

A rapid and sensitive LC-MS/MS method for quantifying oxycodone, noroxycodone, oxymorphone and noroxymorphone in human plasma to support pharmacokinetic drug interaction studies of oxycodone.

A sensitive and reliable LC-MS/MS method was developed and validated for the quantification of oxycodone and metabolites in human plasma. The method has a runtime of 6min and a sensitivity of 0.1μg/L for all analytes. Sample preparation consisted of protein precipitation. Separation was performed on a Kinetix biphenyl column (2.1 × 100 mm, 1.7μm), using ammonium formate 5mm in 0.1% aqueous formic acid and methanol LC-MS grade 100% in gradient elution at a flow rate of 0.4ml/min. Detection was performed in multiple reaction monitoring mode using positive electrospray ionization. The method was linear over the calibration range of 0.1-25.0μg/L for oxycodone, noroxycodone and noroxymorphone and 0.1-5.0μg/L for oxymorphone. The method demonstrated good performance in terms of intra- and interday accuracy (86.5-110.3%) and precision (CV 1.7-9.3%). The criteria for the matrix effect were met (CV < 15%) except for noroxymorphone, for which an additional method was applied to compensate for the matrix effect. Whole blood samples were stable for 4h at room temperature. Plasma samples were stable for 24 h at room temperature and 3months at -20°C. Furthermore, the method was successfully applied in a pharmacokinetic drug interaction study of oxycodone and enzalutamide in patients with prostate cancer.

Pegylated liposome encapsulating docetaxel using microfluidic mixing technique: Process optimization and results in breast cancer models

The development of nanoparticles could help to improve the efficacy/toxicity balance of drugs. This project aimed to develop liposomes and immunoliposomes using microfluidic mixing technology.Various formulation tests were carried out to obtain liposomes that met the established specifications. The liposomes were then characterized in terms of size, polydispersity index (PDI), docetaxel encapsulation rate and lamellarity. Antiproliferative activity was tested in human breast cancer models ranging from near-negative (MDA-MB-231), positive (MDA-MB-453) to HER2 positive. Pharmacokinetic studies were performed in C57BL/6 mice.Numerous batches of liposomes were synthesised using identical molar ratios and by varying the microfluidic parameters TFR, FRR and buffer. All synthesized liposomes have a size < 200 nm, but only Lipo-1, Lipo-6, Lipo-7, Lipo-8 have a PDI < 0.2, which meets our initial requirements. The size of the liposomes was correlated with the total FRR, for a 1:1 FRR the size is 122.2 ± 12.3 nm, whereas for a 1:3 FRR the size obtained is 163.4 ± 34.0 nm (p = 0.019. Three batches of liposomes were obtained with high docetaxel encapsulation rates > 80 %. Furthermore, in vitro studies on breast cancer cell lines demonstrated the efficacy of liposomes obtained by microfluidic mixing technique. These liposomes also showed improved pharmacokinetics compared to free docetaxel, with a longer half-life and higher AUC (3-fold and 3.5-fold increase for the immunoliposome, respectively).This suggests that switching to the microfluidic process will produce batches of liposomes with the same characteristics in terms of in vitro properties and efficacy, as well as the ability to release the encapsulated drug over time in vivo. This time-efficiency of the microfluidic technique is critical, especially in the early stages of development.

Development and validation of a dried blood spots assay for metabolic profiling of ginsenosides using ultra-high performance liquid chromatography-mass spectrometry

Ethnopharmacological relevancePanax ginseng C.A. Meyer., a famous and valuable traditional Chinese medicine with thousand years of history for its healthcare and therapeutic effects. It is necessary and meaningful to study the pharmacokinetic behavior of ginsenosides in vivo as they are the most active components. Dried blood spots (DBS) are a mature and advanced blood collection method with meet the needs for the measurement of numerous analytes. Aim of the studyThis study aimed to explore the feasibility on DBS in the metabolic profile analysis of complex herbal products. Materials and methodsAn ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) method was developed and validated for the determination of ginsenosides. The preparation of DBS samples was conducted by spiking the whole blood with analytes to obtain 20 μL of blood spots on Whatman 903 collection card. A punched dish of 10 mm in diameter was extracted with 70 % methanol aqueous solution, digoxin was used as an internal standard. Target compounds were separated on a Waters T3 column (2.1 × 100 mm, 1.8 μm) with acetonitrile and water (0.1 % formic acid) at a flow rate of 0.4 mL/min. ResultsThe various ginsenosides showed good linearity in the range of 1–2000 ng/mL. The extraction recoveries and matrix effects of the target analytes were above 82.2%. The intra- and inter-batch accuracy and precision were within the limits of ≤15% for all tested concentrations. Moreover, the collected dried blood spot samples could be stably stored at room temperature for 14 days and 4 °C for 1 month without being affected. And it is delightful that the DBS-based analysis is compatible or even superior to the conventional protein precipitation in terms of sensitivity, linearity, and stability. In particular, the target analytes are stable in the DBS sampling under normal storing condition and the sensitivity for some trace metabolites of ginsenosides, such as 20(S)-Rg3, 20(R)-Rg3, F1, Rk1, Rg5, etc. increases 3–4 folds as evaluated by LLOQ. ConclusionsThe established method was successfully applied to pharmacokinetic studies of ginseng extract in mice, this suggests a more feasible strategy for pharmacokinetic study of traditional and natural medicines both in animal tests and clinical trials.

Abstract CT167: Trial in progress: Phase 1 dose escalation study of T-1101, a first-in-class oral Hec1/Nek2 inhibitor, in patients with advanced refractory solid tumors

Abstract Background: T-1101, a novel small molecule, is the first-in-class oral agent that specifically disrupts the interaction between two commonly overexpressed, critical mitotic regulators, Hec1 and Nek2, within cancer cells. Such disruption leads to abnormal mitosis followed by apoptosis of cancer cells and provides a potential therapeutic strategy for cancer treatment. T-1101, with growth inhibition concentrations (IC50) ranging from14 to 74 nM across various human cancer cell lines, exhibited potent anti-liver and breastcancer activities in vivo, and highly active (IC50 7-19 nM) in MDR (multiple drugresistance) expressing cell lines. The effective inhibitory dose of T-1101 was determined to be between 10 and 25 mg/kg twice a day in xenograft animal models. Moreover, T-1101 has synergistic activity when combined with other anticancer drugs such as doxorubicin, topotecan and paclitaxel etc. Clinically, oral powder for constitution (OPC) form was first used in the initial study. To improve better patient compliance, the capsule (CAP) form is then deployed in current T-1101’s phase 1 study. Methods: Two T-1101 oral formulations (OPC and CAP) have been designed for the first-in-human, multi-center, open-label, dose-escalation studies to evaluate the safety, tolerability and establish the Recommended Phase 2 Dose (RP2D) in subjects with advanced refractory solid tumors. The secondary objectives are to assess the pharmacokinetics (PK) and therapeutic response after receiving treatment. DLT was determined within the first treatment cycle. Patients showing clinical benefit after first 2cycles of T-1101may enter extension cohort to continue the treatment. In OPC 3+3 escalation study (NCT03195764, NCT03349073), T-1101 was administered orally once daily, days 1 to 14 every 21 days per cycle with 8 planned dose levels at dose of 9, 18, 36, 54, 72, 90, 108 to 126 mg/m2. The OPC study was terminated at 36 mg/m2 before the primary endpoint (determination of maximum tolerated dose; MTD) was reached and subsequent dosing level will be evaluated with the CAP formulation. Based on the 52% of relative oral bioavailability (%F) of CAP versus OPC in preclinical Beagle dogs’ PK study, the starting dose of CAP form of T-1101 was determined at 100 mg daily forconsecutive 28-day per cycle for 2 cycles with dose levels of 100, 200, 225, 250, 300 and 350 mg/day. The accelerated titration and Bayesian Optimal Interval (BOIN) designs are used for the T-1101 capsule dose escalation study (NCT04685473), in which one subject will be enrolled per dose level until one subject have DLT or two subjects experience ≥ Grade 2 drug-related AE during Cycle 1 at any dose level, then the dose escalation will follow the BOIN design. Cohorts 1 (100 mg/day) 2 (200 mg/day) and 3 (225 mg/day) have been completed without DLT. As of November 2023, the trial remains open to enrollment. Citation Format: Wu-Chou Su, Li-Yuan Bai, Hui-Hua Hsiao, Her-Shyong Shiah, Yu-Min Yeh, Shang-Hung Chen, Shang-Yin Wu, Hui-Ching Wang, Hui-Jen Tsai, Kwang-Yu Chang, Jui-Hung Tsai, Chun-Hui Lee, Chieh Hua Lee, Yu-Sheng Chao, Li-Tzong Chen. Trial in progress: Phase 1 dose escalation study of T-1101, a first-in-class oral Hec1/Nek2 inhibitor, in patients with advanced refractory solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT167.

Abstract LB124: Targeting NaPi2b with a novel dual TOP1i ADC that shows excellent biophysical properties and high efficacy in vivo

Abstract The Araris site-specific and one-step linker conjugation technology aims at generating stable, safe and highly potent ADCs without the need for antibody engineering prior to payload conjugation. Here, we generated an anti-NaPi2b ADC with two different Topoisomerase-1 inhibitors (TOP1i) as payloads that shows excellent efficacy vs anti-NaPi2b ADCs that were unsuccessful in clinical trials due to low therapeutic indices (TI), preventing administration at therapeutically active doses. The Araris ADC was designed to combine two features in one ADC to maximize tumor-specific activity by using two different TOP1i payloads: one potent TOP1i that is able to exert bystander activity to address tumor heterogeneity and low-target expression and one exatecan derivative (DAR2) that accumulates in cells (low bystander activity) to achieve greater potency. This novel ADC is characterized by a well-defined drug-to-antibody ratio (DAR) of 4 (DAR2+2), high homogeneity and purity and shows high stability under stressed conditions. In in vitro assays on various target-positive cell lines with different NaPi2b expression levels, the Araris ADC demonstrated nM-potency in cell cytotoxicity assays, similar to the clinical NaPi2b ADCs lifastuzumab vedotin and upifitamab rilsodotin but being much less toxic to target-negative cells. Moreover, this ADC showed excellent stability in mouse and human sera, exemplified by the absence of payload deconjugation or linker cleavage. Most importantly, the ADC was extremely stable in circulation as shown in pharmacokinetic studies in rodents, demonstrating an exposure profile comparable to the unmodified parent antibody. Strikingly, in a high-expressing OVCAR-3 xenograft model, the Araris ADC administered as a single dose at 9 mg/kg on day 0 led to very high anti-tumor activity, essentially leading to tumor eradication and a long lasting anti-tumor response in all treated animals. We here show first encouraging results on a novel concept of combining TOP1i payloads that have two different features in one ADC to maximize efficacy and tolerability. We believe that this concept in combination with a stable payload attachment at low DAR and an excellent exposure may help to develop ADCs with an improved therapeutic index for various solid tumor indications. The initial results indicate that this ADC may overcome the limitations of current clinical programs against NaPi2b and has the potential to be a first-in-class ADC. Citation Format: Isabella Attinger-Toller, Philipp Probst, Lia Kallenberger, Emma Renard, Romain Bertrand, Rachael Fay, Roger Santimaria, Patrick Maurhofer, Dragan Grabulovski, Bernd Schlereth, Philipp Rene Spycher. Targeting NaPi2b with a novel dual TOP1i ADC that shows excellent biophysical properties and high efficacy in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB124.

Abstract LB437: Development of a bladder cancer-on-a-chip assay to assess the invasive potential of bladder cancer cells

Abstract Goals: The primary goal of this study was to develop a 3D functional bioassay to assess the relative invasiveness of bladder cancer cells. This model will support the testing of migrastatic drugs and investigation of the molecular mechanisms which allow for bladder cancer cell invasion to occur. Methods: Our model uses an organ-on-a-chip platform to assess bladder cancer cell invasiveness. This platform supports 3D culture of cells as well as pharmacokinetic studies. Our chips were designed to have a center channel to hold cells supported in Matrigel®, 2 adjacent side channels filled with Matrigel® only, and 2 outer media channels. Total cell and Matrigel® side channel length is 3 cm, channel height is 150 µm, and each channel width is 1 mm. Four bladder cancer cell lines (MB49, T24, J82, RT4) and cells isolated from a mouse bladder were used to develop our model. Cells were mixed with 1:1 media and Matrigel® and a total of 5,000 cells/µl introduced into the center channel. The 2 adjacent side channels were then filled with Matrigel®. The upper media channel was filled with 10% FBS cell culture media while the lower media channel was filled with 1% charcoal stripped cell culture media to thereby create a nutrient and growth factor gradient. Invasion of cells into the Matrigel®-containing side channels was assessed every 24 hours. Using the ImageXpress machine (Molecular Dynamics), we measured the furthest distance travelled by the cells. The chips were then fixed in 4% paraformaldehyde and stained using FITC-phalloidin and DAPI. Results: J82 and T24 cell lines, derived from patients with muscle invasive bladder cancer, and the MB49 cell line, a highly invasive mouse bladder cancer cell line, started invading into the Matrigel® side channels within 24 hours. T24, J82, and MB49 cells moved a maximum of 110, 87, and 170 µm by 48 hours, respectively. In contrast, RT4 cells, derived from a patient with non-invasive bladder cancer, took 48 hours to invade the Matrigel® channels and only invaded a maximum of 3 µm. Cells isolated from a mouse bladder did not invade into the Matrigel® side channels but survived within the chips for over 20 days. Staining of chips with DAPI and FITC-phalloidin allowed for clear visualization of cells and the actin cytoskeleton and demonstrated that immunostaining of cells within chips is possible. Conclusions: Our chip model allows for studying the invasiveness of bladder cancer cells and immunostaining experiments which can be used to assess the molecular mechanisms which drive invasion. It can also support the growth and assessment of primary cells. This model has the potential to improve bladder cancer patient treatments and outcomes by providing a physiologically relevant system to test new and existing drug combinations and to better understand the molecular mechanisms which drive bladder cancer cell invasion. Citation Format: Desiree Ewell, Nita Vue, Sakib Moinuddin, Tanoy Sarkar, Fakhrul Ahsan, Ruth L. Vinall. Development of a bladder cancer-on-a-chip assay to assess the invasive potential of bladder cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB437.

Comparative Pharmacokinetics Study of the Leutragin Peptide Drug in Blood Serum and Lung Tissue in C57BL/6Y Mice after Single Inhalation Administration

This paper presents a study into the pharmacokinetics of a new inhaled anti-inflammatory hexapeptide, registered as “Leutragin”. This drug is used as a new treatment approach for viral pneumonias, whose severe course is directly related to the cytokine inflammatory cascade referred to as a cytokine storm. The study involved investigation of lung tissue and serum after a single inhalation administration of Leutragin to mice of the C57BL/6Y line at a dose of 150 mg/kg. The time required to reach the maximum concentration (Tmax) of Leutragin in serum and lung was 30 min and 10 min, respectively. The maximum concentration (Cmax) in lung was 358.5 ng/g, which exceeded the concentration maximum for blood (53.84 ng/g) by over six times. It was found that, after inhalation administration, Leutragin is rather rapidly eliminated from the body with the half-life of the drug (t1/2el) from blood serum and lungs ranging from 25.8 to 38.9 min.

Abstract LB034: First-in-class compounds targeting the MIEN1 signaling pathway: A breakthrough approach for breast and prostate cancer therapy

Abstract We report the identification and complete characterization of first-in-class molecules targeting the MIEN1 signaling pathway in cancer. Migration and invasion enhancer 1 (MIEN1) overexpression characterizes several cancers and facilitates cancer cell migration and invasion. Leveraging conserved ITAM and prenylation motifs within MIEN1, we identified potent anti-cancer peptides. Among them, bioactive peptides LA3IK and RP-7 induced pronounced transcriptomic and protein expression changes at sub-IC50 concentrations. The peptides effectively inhibited genes and proteins driving cancer cell migration, invasion, and EMT pathways, concurrently suppressing EGF-induced NF-kB nuclear translocation in metastatic breast cancer cells. Specifically, peptides targeted the same signal transduction pathway initiated by MIEN1. Molecular docking and circular dichroism spectroscopy indicated the formation of MIEN1-peptide complexes. The third-positioned isoleucine in LA3IK and CVIL motif in RP-7 were crucial for inhibiting breast cancer cell migration. This is evident from the limited migration inhibition observed when MDA-MB-231 cells were treated with scrambled peptides LA3IK-SCR and RP-7-SCR. Additionally, LA3IK and RP-7 effectively suppressed tumor growth in an orthotopic breast cancer model. Notably, mice tolerated high peptide doses of up to 90 mg/Kg well, surpassing significantly lower doses of 5 mg/Kg intravenously (iv) and 30 mg/Kg intraperitoneally (ip) used in both in vivo pharmacokinetic studies and orthotopic mouse model assays. D-isomers of LA3IK and RP-7 showed enhanced anti-cancer activity compared to their L-isomers. D-LA3IK remained stable in mouse plasma for 24 h with 75% remaining, exhibiting superior pharmacokinetic properties over D/L-RP-7. In summary, our findings mark the first report of short peptides based on MIEN1 protein sequence capable of inhibiting cancer signaling pathways, effectively impeding cancer progression both in vitro and in vivo. Citation Format: Amit Kumar Tripathi, Jamboor K. Vishwanatha. First-in-class compounds targeting the MIEN1 signaling pathway: A breakthrough approach for breast and prostate cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB034.

Twice-Daily Dolutegravir Based Antiretroviral Therapy with One Month of Daily Rifapentine and Isoniazid (1HP) for TB Prevention.

One month of daily rifapentine + isoniazid (1HP) is an effective, ultrashort option for TB prevention in people with HIV (PWH). However, rifapentine may decrease antiretroviral drug concentrations and increase the risk of virologic failure. ACTG A5372 evaluated the effect of 1HP on the pharmacokinetics of twice daily dolutegravir. A5372 was a multicenter, pharmacokinetic study in PWH (≥18 years) already on dolutegravir-containing antiretroviral therapy with HIV RNA < 50 copies/mL. Participants received daily rifapentine/isoniazid (600mg/300mg) for 28 days as part of 1HP. Dolutegravir was increased to 50mg twice daily during 1HP and intensive pharmacokinetic sampling was performed on day 0 (before 1HP) and on the final day of 1HP treatment. Thirty-two participants (41% female; 66% Black/African; median (Q1, Q3) age 42 (34, 49) years) were included in the pharmacokinetic analysis. Thirty-one of 32 had HIV RNA levels <50 copies/mL at the end of 1HP dosing. One participant had an HIV RNA of 160 copies/mL at day 28, with HIV RNA <50 copies/mL upon repeat testing on day 42. The median (Q1, Q3) dolutegravir trough concentration was 1751 ng/mL (1195, 2542) on day 0 vs. 1987ng/mL (1331, 2278) on day 28 (day 28:day 0 GMR 1.05, [90% CI 0.93-1.2]; p = 0.43). No serious adverse events were reported. Dolutegravir trough concentrations with 50mg twice daily dosing during 1HP treatment were greater than those with standard dose dolutegravir once daily without 1HP. These pharmacokinetic, virologic, and safety data provide support for twice daily dolutegravir use in combination with 1HP for TB prevention.

Unified Methodology for the Primary Preclinical In Vivo Screening of New Anticoagulant Pharmaceutical Agents from Hematophagous Organisms.

The development of novel anticoagulants requires a comprehensive investigational approach that is capable of characterizing different aspects of antithrombotic activity. The necessary experiments include both in vitro assays and studies on animal models. The required in vivo approaches include the assessment of pharmacokinetic and pharmacodynamic profiles and studies of hemorrhagic and antithrombotic effects. Comparison of anticoagulants with different mechanisms of action and administration types requires unification of the experiment scheme and its adaptation to existing laboratory conditions. The rodent thrombosis models in combination with the assessment of hemostasis parameters and hematological analysis are the classic methods for conducting preclinical studies. We report an approach for the comparative study of the activity of different anticoagulants in vivo, including the investigation of pharmacodynamics and the assessment of hemorrhagic effects (tail-cut bleeding model) and pathological thrombus formation (inferior vena cava stenosis model of venous thrombosis). The reproducibility and uniformity of our set of experiments were illustrated on unfractionated heparin and dabigatran etexilate (the most common pharmaceuticals in antithrombic therapy) as comparator drugs and an experimental drug variegin from the tick Amblyomma variegatum. Variegin is notorious since it is a potential analogue of bivalirudin (Angiomax, Novartis AG, Basel, Switzerland), which is now being actively introduced into antithrombotic therapy.

Quantification of the aromatase inhibitor letrozole and its carbinol metabolite in mouse plasma by UHPLC-MS/MS

A liquid chromatography - electrospray ionization-mass spectrometry (LC-ESI-MS) method was developed for the quantification of letrozole, a third-generation aromatase inhibitor, and its main carbinol metabolite (CM) in support of murine pharmacokinetic studies. Using polarity switching, simultaneous ESI-MS measurement of letrozole and CM was achieved in positive and negative mode, respectively. The assay procedure involved a one-step protein precipitation and extraction of all analytes from mouse plasma requiring only 5 μL of sample. Separation was optimized on an Accucore aQ column with gradient elution at a flow rate of 0.4 mL/min in 5 min. Two calibration curves per day over four consecutive measurement days showed satisfactory linear responses (r2 > 0.99) over concentration ranges of 5–1000 ng/mL and 20–2000 ng/mL for letrozole and CM, respectively. No matrix effect was found, and the mean extraction recoveries were 103–108 % for letrozole and 99.8–107 % for CM. Precision and accuracy within a single run and over four consecutive measurement days were verified to be within acceptable limits. Application of the developed method to preclinical pharmacokinetic studies in mice receiving oral letrozole at a dose 1 or 10 mg/kg revealed that the systemic exposure to letrozole was dose-, formulation-, and strain-dependent. These findings may inform the future design of preclinical studies aimed at refining the pharmacological profile of this clinically important drug.

Development of an ELISA with acidification treatment for an antibody conjugate incorporating Exatecans

The successful development of Sacituzumab Govitecan and Trastuzumab Deruxtecan has made camptothecin derivatives one of the most popular payloads for antibody-drug conjugates (ADCs). Camptothecin and its derivatives all exist in a pH-dependent equilibrium between the carboxylate and lactone forms. Such transformation may lead to differences in the ratio of the two molecular forms in calibration standards and biological matrix (bio-matrix) samples, thereby leading to inaccurate conjugated antibody results. In this study, we reported an enzyme-linked immunosorbent assay (ELISA) free of the aforementioned influence for the detection of the Exatecans-conjugated antibody (conjugated SM001) in cynomolgus monkey serum. The assay was developed by first acidifying all samples with glacial acetic acid (HAc), then performing neutralization and thereafter capturing conjugated SM001 with anti-Exatecan monoclonal antibody (mAb) and detecting it with biotinylated Nectin4 (hNectin4-Bio) and horseradish peroxidase-labeled streptavidin (SA-HRP). Results showed that all tested performance parameters met the acceptance criteria. The conjugated SM001 concentrations obtained were in parallel to but slightly lower than total antibody (TAb) throughout the pharmacokinetic (PK) study, revealing that the assay strategy implemented for conjugated SM001 measurement worked well for the elimination of interference triggered by the heterogeneous existence of the lactone and carboxylate forms of Exatecan (lactone-Exatecan and carboxylate-Exatecan).