Clinical Pharmacokinetics Research Articles

Physiologically Based Biopharmaceutics Modeling for Gefapixant IR Formulation Development and Defining the Bioequivalence Dissolution Safe Space.

Gefapixant is a weakly basic drug which has been formulated as an immediate release tablet for oral administration. A physiologically based biopharmaceutics model (PBBM) was developed based on gefapixant physicochemical properties and clinical pharmacokinetics to aid formulation selection, bioequivalence safe space assessment and dissolution specification settings. In vitro dissolution profiles of different free base and citrate salt formulations were used as an input to the model. The model was validated against the results of independent studies, which included a bioequivalence and a relative bioavailability study, as well as a human ADME study, all meeting acceptance criteria of prediction errors ≤ 20% for both Cmax and AUC. PBBM was also applied to evaluate gastric pH-mediated drug-drug-interaction potential with co-administration of a proton pump inhibitor (PPI), omeprazole. Model results showed good agreement with clinical data in which omeprazole lowered gefapixant exposure for the free base formulation but did not significantly alter gefapixant pharmacokinetics for the citrate based commercial drug product. An extended virtual dissolution bioequivalence safe space was established. Gefapixant drug product batches are anticipated to be bioequivalent with the clinical reference batch when their dissolution is > 80% in 60 minutes. PBBM established a wide dissolution bioequivalence space as part of assuring product quality.

Investigating clinical pharmacokinetics of brivaracetam by using a pharmacokinetic modeling approach

The development of technology and the processing speed of computing machines have facilitated the evaluation of advanced pharmacokinetic (PK) models, making modeling processes simple and faster. The present model aims to analyze the PK of brivaracetam (BRV) in healthy and diseased populations. A comprehensive literature review was conducted to incorporate the BRV plasma concentration data and its input parameters into PK-Sim software, leading to the creation of intravenous (IV) and oral models for both populations. The developed physiologically based pharmacokinetic (PBPK) model of BRV was then assessed using the visual predictive checks, mean observed/predicted ratios (Robs/pre), and average fold error for PK parameters including the maximum systemic concentration (Cmax), the area under the curve at time 0 to t (AUC0–∞), and drug clearance (CL). The PBPK model of BRV demonstrated that mean Robs/pre ratios of the PK parameters remained within the acceptable limits when assessed against a twofold error margin. Furthermore, model predictions were carried out to assess how AUC0–∞ is affected following the administration of BRV in individuals with varying degrees of liver cirrhosis, ranging from different child–pugh (CP) scores like A, B, and C. Moreover, dose adjustments were recommended by considering the variations in Cmax and CL in various kidney disease stages (mild to severe).

Clinical pharmacokinetics and pharmacodynamics of empagliflozin in patients with heart failure.

The aim of this work is to compare empagliflozin systemic exposure between patients with heart failure (HF) and patients with type 2 diabetes (T2D). Analysis of covariance (ANCOVA) compared steady state trough concentrations of empagliflozin 10mg in EMPEROR-reduced (patients with HF with reduced ejection fraction [HFrEF]) and EMPA-REG OUTCOME (patients with T2D at high cardiovascular risk) after adjusting for eGFR and body weight. The difference in geometric Mean (gMean) empagliflozin steady state trough concentration of 10mg empagliflozin between EMPEROR-reduced and EMPA-REG OUTCOME was 1.47-fold (95% confidence interval [CI]: 1.33, 1.63). Additionally, ANCOVA for the sub-group of patients with both T2D and HF conditions revealed a difference in gMean steady state trough concentration of 1.53-fold (95% CI: 1.26, 1.85). In both patients with HFrEF and HF with preserved EF (HFpEF), there was no major difference in empagliflozin steady state trough exposure by New York Heart Association (NYHA) classification or by use of angiotensin receptor-neprilysin inhibitor as comedication. A weak positive correlation was observed for NT-proBNP at Week 12 and empagliflozin steady state trough concentration in both patients with HFrEF and HFpEF (Pearson correlation r = 0.19). Plasma concentrations of empagliflozin in patients with HF were higher compared to patients with T2D, but the exposure resulting from the 10mg dose was still below the exposure resulting from the dose of 25 mg approved in patients with T2D. The difference in exposure was attributable to demographic characteristics and HF-induced pathophysiological changes. Overall, the results confirm 10mg as the appropriate empagliflozin dose in patients with HF.

Ceftobiprole quantification in human serum by HPLC-UV to implement routine TDM in clinical practice

Background and aimsCeftobiprole is a recent 5th generation parenteral cephalosporin with antibacterial activity against a large range Gram+ and Gram− bacteria. Therapeutic drug monitoring (TDM) is an essential tool for maintaining plasma concentrations of antibiotics above the MIC by the end of the dosing interval, thus preventing the resistant strain diffusion. TDM is already recommended for other cephalosporins, and it is a reasonable tool contributing to the safety and efficacy of these drugs. During the treatment of patients in real-life, a number of pharmacokinetic (PK) changes not normally seen in healthy volunteers can occur which can impair the pharmacokinetic/pharmacodynamic target attainment.We aimed to develop simple and rapid HPLC-UV method for determination of ceftobiprole in human serum to implement TDM in clinical practice and support PKs and pharmacokinetic/pharmacodynamic (PK/PD) studies. Materials and methodsSamples preparation of calibration standards, QC, and anonymous patients serum samples was performed by protein precipitation by adding 0.01 ml of sulphosalicylic acid at 30 % to 0.1 ml of each sample. Then samples were vortexed and the centrifuged at 12,000 rpm for 10 min at 4 °C. Fifty microlitres of clear supernatant were diluted 1:1 with mobile phase and transferred into HPLC autosampler held at 8 °C. Chromatographic separation was carried out in a gradient mode at 35 °C on an ultra-Biphenyl column using a Thermo Scientific chromatographic system with a Diode array. Data management was performed with Chromeleon 7.4 software. ResultsThe HPLC-UV method proved to be linear over wide concentration ranges (0.5–50.0 mg/L) and was accurate and reproducible in the absence of matrix effects, allowing for robust, specific, and rapid quantification of ceftobiprole from a low amount of serum (0.1 mL). The mean steady state Ctrough and Cend values measured in the anonymous patients’ samples were 6.26 ± 3.81 mg/L and 22.56 ± 15.69 mg/L, respectively. ConclusionsWe report a broadened simple and fast HPLC with UV detection method for quantification of ceftobiprole in human serum to implement ceftobiprole TDM as clinical routine, and support future (PK/PD) studies in special patients’ population.

Integrated PBPK-EO modeling of osimertinib to predict plasma concentrations and intracranial EGFR engagement in patients with brain metastases

The purpose of this study was to develop and validate a physiologically based pharmacokinetic (PBPK) model combined with an EGFR occupancy (EO) model for osimertinib (OSI) to predict plasma trough concentration (Ctrough) and the intracranial time-course of EGFR (T790M and L858R mutants) engagement in patient populations. The PBPK model was also used to investigate the key factors affecting OSI pharmacokinetics (PK) and intracranial EGFR engagement, analyze resistance to the target mutation C797S, and determine optimal dosing regimens when used alone and in drug-drug interactions (DDIs). A population PBPK-EO model of OSI was developed using physicochemical, biochemical, binding kinetic, and physiological properties, and then validated using nine clinical PK studies, observed EO study, and two clinical DDI studies. The PBPK-EO model demonstrated good consistency with observed data, with most prediction-to-observation ratios falling within the range of 0.7 to 1.3 for plasma AUC, Cmax, Ctrough and intracranial free concentration. The simulated time-course of C797S occupancy by the PBPK model was much lower than T790M and L858R occupancy, providing an explanation for OSI on-target resistance to the C797S mutation. The PBPK model identified ABCB1 CLint,u, albumin level, and EGFR expression as key factors affecting plasma Ctrough and intracranial EO for OSI. Additionally, PBPK-EO simulations indicated that the optimal dosing regimen for OSI in patients with brain metastases is either 80 mg once daily (OD) or 160 mg OD, or 40 mg or 80 mg twice daily (BID). When used concomitantly with CYP enzyme perpetrators, the PBPK-EO model suggested appropriate dosing regimens of 80 mg OD with fluvoxamine (FLUV) itraconazole (ITR) or fluvoxamine (FLUC) for co-administration and an increase to 160 mg OD with rifampicin (RIF) or efavirenz (EFA). In conclusion, the PBPK-EO model has been shown to be capable of simulating the pharmacokinetic concentration–time profiles and the time-course of EGFR engagement for OSI, as well as determining the optimum dosing in various clinical situations.

Randomized controlled, open-label, phase IIb/III study of lurbinectedin in combination with doxorubicin versus doxorubicin alone as first-line treatment in patients with metastatic leiomyosarcoma.

TPS11590 Background: Lurbinectedin (LUR) is a synthetic chemical entity structurally related to trabectedin that inhibits oncogenic transcription and is active in tumors addicted to transcription. Synergistic activity of the combination of LUR with Doxorubicin (DOX) was found in solid tumors. Preliminary results from two trials showed efficacy for LUR/DOX in anthracycline-naïve advanced Leiomyosarcoma (LMS) (1st or 2nd line) at different doses. In a phase 2 trial in soft tissue sarcoma (STS) patients (pts) (mostly with LMS: 12/20 pts), a combination of DOX 50 mg/m2 + LUR 2 mg/m2 Day (D)1 q3wk resulted in a response rate (RR) of 35% (4/7 LMS pts responding) and a disease control rate (DCR) at 24 wks of 40% (1). A phase 1b/2 trial in 10 advanced STS pts found a RR of 60% (5 were LMS, with 3 partial responses) treated at DOX 25 mg/m2 D1 or D1,D8 + LUR 3.2 mg/m2 D1 q3wk, (2). The promising results of these trials provide a rationale for further exploring this combination in a phase 2b/3 trial as first-line therapy for metastatic LMS (SaLuDo - NCT06088290). Methods: SaLuDo is a randomized, open-label study evaluating LUR in combination with DOX compared to DOX alone as first-line treatment of pts with metastatic LMS. The primary endpoint is progression-free survival (PFS) according to Independent Radiological committee (IRC). Secondary endpoints include overall survival, PFS according to Investigator assessment (IA), overall response rate, duration of response, and clinical benefit rate (according to IRC and IA), safety profile, patient-reported outcomes, pharmacokinetics, and exploratory pharmacogenomic analysis. Main inclusion criteria include age ≥ 18 years, confirmed diagnosis of metastatic LMS, and no prior systemic treatment for metastatic disease. Exclusion criteria include prior treatment with anthracyclines, lurbinectedin or trabectedin. The phase 2b part of the study will randomize approximately 120 pts into 3 arms (1:1:1): Control arm (DOX 75 mg/m2 D1 q3wk; experimental ARM A (DOX 50 mg/m2 D1 + LUR 2.2 mg/m2 D1 + 1ry GCSF prophylaxis q3wk), and experimental ARM B (DOX 25 mg/m2 D1 + LUR 3.2mg/m2 D1 + 1ry GCSF prophylaxis q3wk). Stratification will be done according to site of primary tumor (uterine vs. soft tissue), sites of metastatic disease (lung as unique site vs. other) and time from diagnosis to study entry (≤ 12 months vs. >12 months). One of the two experimental arms will be dropped out at the end of phase 2b. The study will then enter the phase 3 part and approximately 120 pts will be randomized 1:1 between the control arm and the selected experimental arm. An Independent Data Monitoring Committee will oversee the conduct of the study. The first patient was randomized in 09/2023. The phase 2b part of the study is ongoing and recruiting patients in Europe and the USA. 1. Cote EJC 2020; 126:21-32. 2. Cote. JCO 2023; 41: Abst 11507. Clinical trial information: NCT06088290 .

Breaking from the paradigm of antibody-drug conjugates: Evaluation of clinical pharmacokinetics and safety of bicycle toxin conjugates (BTCs).

3088 Background: Bicycle toxin conjugates (BTCs) are chemically synthesized molecules comprising a small (~4.5 kDa) bicyclic peptide linked to a cytotoxin. BT8009 and BT5528 are BTCs linked to monomethyl auristatin E (MMAE) targeting nectin-4 and EphA2, respectively, and have shown preliminary activity. BTCs are a unique therapeutic class of small size, with corresponding pharmacokinetic (PK) properties distinct from antibody-drug conjugates (ADCs). MMAE-containing ADCs demonstrate anti-tumor efficacy but substantial safety issues attributable to the slow clearance of ADCs, which increases uptake into off-target tissues and exposure to plasma proteases (ie, payload release).To evaluate BTC PK and safety relative to ADCs, we present results of the ongoing Phase I/II trials for BT8009 (NCT04561362) and BT5528 (NCT04180371). Methods: Patients with advanced solid tumors receiving IV BT8009 (n=147) or BT5528 (n=109) monotherapy were evaluated. Doses were given as 2.5–10 mg/m2 weekly (QW), every 2 weeks (Q2W), or 2 weeks on/1 week off for BT8009 and 2.2–10 mg/m2 QW or Q2W for BT5528. Population PK (PPK) models for BT8009 and BT5528 were developed. PK exposures (Cycle 1 area under the concentration curve [AUC]) for BTCs, conjugated MMAE, and unconjugated MMAE were simulated for 5 mg/m2 QW BT8009 and BT5528 and compared with those of an MMAE-containing ADC (approved regimen, using the PPK model in the literature). Treatment-related adverse events (TRAEs) were tabulated for BT8009 and BT5528. Results: BTCparent drugs were rapidly eliminated (half-life [t1/2] <1 hour) while unconjugated MMAE exhibited persistent exposures and gradual elimination (MMAE t1/2, 1.9 days [D] for both BT8009 and BT5528), in contrast with the ADC (parent drug t1/2, 3.6 D; MMAE t1/2, 2.6 D). Conjugated MMAE exposures for the ADC were higher than for BT8009 and BT5528 (75- and 73-fold, respectively). Unconjugated MMAE exposures for BT8009 and BT5528 were comparable to the ADC (25% and 8% higher, respectively). Among the BTC regimens most thoroughly evaluated (BT8009 5 mg/m2 QW and BT5528 6.5 mg/m2 Q2W), TRAEs of interest occurred with low frequency and severity (Table). Conclusions: Preliminary data show substantial differences between BTC and ADC PK, and a promising BTC safety profile, possibly resulting from the distinct PK and selectivity (and specificity) of Bicycle peptides. These data highlight the potential value of BTCs as a platform for developing therapies against advanced malignancies. Clinical trial information: NCT04561362 and NCT04180371 . [Table: see text]

Physiologically based pharmacokinetic modeling of CYP2C8 substrate rosiglitazone and its metabolite to predict metabolic drug-drug interaction

Rosiglitazone is an activator of nuclear peroxisome proliferator-activated (PPAR) receptor gamma used in the treatment of type 2 diabetes mellitus. The elimination of rosiglitazone occurs mainly via metabolism, with major contribution by enzyme cytochrome P450 (CYP) 2C8. Primary routes of rosiglitazone metabolism are N-demethylation and hydroxylation. Modulation of CYP2C8 activity by co-administered drugs lead to prominent changes in the exposure of rosiglitazone and its metabolites. Here, we attempt to develop mechanistic parent-metabolite physiologically based pharmacokinetic (PBPK) model for rosiglitazone. Our goal is to predict potential drug-drug interaction (DDI) and consequent changes in metabolite N-desmethyl rosiglitazone exposure. The PBPK modeling was performed in the PKSim® software using clinical pharmacokinetics data from literature. The contribution to N-desmethyl rosiglitazone formation by CYP2C8 was delineated using vitro metabolite formation rates from recombinant enzyme system. Developed model was verified for prediction of rosiglitazone DDI potential and its metabolite exposure based on observed clinical DDI studies. Developed model exhibited good predictive performance both for rosiglitazone and N-desmethyl rosiglitazone respectively, evaluated based on commonly acceptable criteria. In conclusion, developed model helps with prediction of CYP2C8 DDI using rosiglitazone as a substrate, as well as changes in metabolite exposure. In vitro data for metabolite formation can be successfully utilized to translate to in vivo conditions.

Nicotine flux and pharmacokinetics-based considerations for early assessment of nicotine delivery systems

In the past few years, technological advancements enabled the development of novel electronic nicotine delivery systems (ENDS). Several empirical measures such as “nicotine flux” are being proposed to evaluate the abuse liability potential of these products. We explored the applicability of nicotine flux for clinical nicotine pharmacokinetics (PK) and 52-week quit success from cigarettes for a wide range of existing nicotine delivery systems. We found that the differences in nicotine flux for various nicotine delivery systems are not related to changes in PK, as nicotine flux does not capture key physiological properties such as nicotine absorption rate. Further, the 52-week quit success and abuse liability potential of nicotine nasal sprays (high nicotine flux product), and nicotine inhalers (nicotine flux similar to ENDS) are low, suggesting that nicotine flux is a poor metric for the assessment of nicotine delivery systems. PK indices are more dependable for characterizing nicotine delivery systems, and a nicotine plasma CmaxTmax > 1 could improve 52-week quit success from cigarettes. However, a single metric may be inadequate to fully assess the abuse liability potential of nicotine delivery systems and needs to be further studied. A combination of in vitro and in silico approaches could potentially address the factors influencing the inhaled aerosol dosimetry and resulting PK of nicotine to provide early insights for ENDS assessments. Further research is required to understand nicotine dosimetry and PK for ad libitum product use, and abuse liability indicators of nicotine delivery systems. This commentary is intended to (1) highlight the need to think beyond a single empirical metric such as nicotine flux, (2) suggest potential PK-based metrics, (3) suggest the use of in vitro and in silico tools to obtain early insights into inhaled aerosol dosimetry for ENDS, and (4) emphasize the importance of considering comprehensive clinical pharmacology outcomes to evaluate nicotine delivery systems.

#606 Impact of real-world off-label dose of apixaban on long-term clinical outcomes in patients with atrial fibrillation and chronic kidney disease

Abstract Background and Aims Apixaban represent one of the cornerstone treatments to prevent cardioembolic events in patients with nonvalvular atrial fibrillation (NVAF). However, the choices of Apixaban dose guided by the decision-making process of the physician, which considers specific according to kidney functions are inconsistent in the real-world practice. The objective of the present study is to evaluate the effects of real-world Off-label dose of Apixaban on long-term clinical outcomes in NVAF patients with chronic kidney disease (CKD). Method Our database of AF patients diagnosed with CKD from 2018 to 2023 was used to obtain laboratory, echocardiography, electrocardiogram (ECG), and clinical outcomes data. Inclusion criteria were all AF patients with CKD using Apixaban. And we compared bleeding, systemic thrombotic events including stroke/systemic embolism and death according to off-label real -world dose of Apixaban. Results Among 635 patients with AF and CKD (76.9 ± 10.4 years), 335 (52.8%) patients took off-label underdosed Apixaban. Difference in the baseline characteristics was not observed among patients including CHA2DS2 VASc score and HASBLED score. During the median 18-month follow-up, a lower incidence of bleeding events (P = 0.001) was observed in the off-label underdosed Apixaban group compared to those with standard dose or off-label overdosed Apixaban. However, there was no significant difference of systemic thrombotic events including stroke/systemic embolism and death according to off-label real-world dose of Apixaban (off-label underdose vs. standard dose, P = 1.000; off-label overdose vs. standard dose, P = 1.000; off-label underdose vs. off-label overdose, P = 0.609). In multivariate analysis, HASBLED score was independent risk factors for bleeding events (OR 9.650; CI 1.998-46.622; P = 0.005). Conclusion Compared with standard or off-label overdose of Apixaban, off-label underdose of Apixaban was associated with a lower risk of bleeding in patients with AF and CKD, with no difference in the risk of stroke/systemic embolism or death, supporting the apixaban dosing tailored to specific clinical features and drug pharmacokinetics of the Asian patients.

The 1st International Babylon Conference on Clinical and Experimental Pharmacological Research: mapping the Iraqi pharmacological research activity and priorities

The proceedings of the 1st International Babylon Conference on Clinical and Experimental Pharmacological Research (taking place at the College of Pharmacy of the University of Babylon, in Hillah, Iraq; May 4-5, 2024) are hereby hosted by the Review of Clinical Pharmacology and Pharmacokinetics – International Edition; a journal that has provided a significant service to the international pharmacological community since 1987. These proceedings include a total of 50 papers (including this editorial) and provide a representative overview of the conference’s rich scientific pro¬gramme. The latter has served two objectives: (i) to facilitate the mapping of the Iraqi pharmacological research and priorities, and (ii) to enable the establishment of international collaborations in the field. In that respect, the proceed¬ings host the inspiring messages of several conference keynote speakers from abroad, and feature a variety of clinical and experimental studies that well relate to the priorities currently set by the Iraqi pharmacological community.

Clinical pharmacokinetics and pharmacodynamics of venetoclax, a selective B-cell lymphoma-2 inhibitor.

Venetoclax, a highly potent BCL-2 inhibitor, is indicated for treatment of some hematologic malignancies as monotherapy, and/or in combination with other agents. Venetoclax pharmacokinetics has been extensively characterized in patients and healthy participants. After oral dosing, the median time to reach maximum plasma concentration ranged from 5 to 8 h and harmonic mean half-life ranged from 14 to 18 h. Food increases venetoclax bioavailability by 3-5-fold and venetoclax should be administered with food to ensure adequate and consistent bioavailability. Venetoclax is eliminated via cytochrome P450 (CYP)3A metabolism, and a negligible amount of unchanged drug is excreted in urine. Strong CYP3A/P-glycoprotein inhibitors increased venetoclax exposures (AUC) by 1.44- to 6.90-fold while a significant decrease (71%) has been observed when dosed with strong CYP3 inducers. Venetoclax does not inhibit or induce CYP enzymes or transporters. Venetoclax pharmacokinetics is not appreciably altered by age, weight, sex, but the exposure is up to twofold higher in participants from Asian countries. Mild-to-severe renal impairment or end-stage renal disease do not alter venetoclax exposures, and venetoclax is not cleared by dialysis. Although mild-to-moderate hepatic impairment does not affect venetoclax exposures, twofold higher exposure was observed in subjects with severe hepatic impairment. Venetoclax exposure is comparable across patients with different hematologic malignancies and healthy participants. Overall, venetoclax exposure is only affected by food and CYP3A modulators and is only higher in Asian subjects and subjects with severe hepatic impairment. Venetoclax exposure-response relationships are malignancy-dependent and can be different between monotherapy and combination therapy.

Venetoclax Clinical Pharmacokinetics After Administration of Crushed, Ground or Whole Tablets

PurposeVenetoclax is a potent, orally bioavailable BCL-2 inhibitor used in the treatment of some hematological malignancies. Crushing tablets may be necessary to help with the administration of venetoclax to patients with swallowing difficulties or patients requiring nasogastric tube feeding. The study was conducted to assess the bioavailability of crushed and finely ground venetoclax tablets relative to whole tablets. MethodsAn open-label, randomized, 3-way, crossover study in 15 healthy adult females was conducted. Venetoclax tablets were administered orally in a crushed, ground or intact form on Day 1 of each period with water following a high-fat breakfast. Pharmacokinetic samples were collected up to 72 hours postdosing. FindingsThe crushed and ground tablets met the bioequivalence criteria (0.80–1.25) relative to the intact tablets with respect to area under the concentration-time curve to time of the last measurable concentration (AUCt) and to infinite time (AUCinf) but exhibited a slightly lower maximum plasma concentration (Cmax). This was not considered clinically significant as only venetoclax overall exposure (AUC) has been shown to correlate with clinical efficacy. There was no change in the physical appearance and the evaluated physicochemical properties of crushed and ground venetoclax tablets after 72 hours of storage at 25°C/60% relative humidity. ImplicationsCrushing or grinding venetoclax tablets before administration could be considered as a viable alternative method of administration for patients who have difficulty swallowing whole venetoclax tablets or patients requiring nasogastric tube feeding. ClinicalTrials.gov identifiersNCT05909553, registered June 12, 2023.

Glycopeptides: Insights Towards Resistance, Clinical Pharmacokinetics and Pharmacodynamics

Glycopeptides: Insights Towards Resistance, Clinical Pharmacokinetics and Pharmacodynamics

Impedimetric sensor based on molecularly imprinted polythionine from deep eutectic solvent for epinephrine determination

Deep eutectic solvents have obtained growing interest in analytical chemistry due to opportunities related the green chemistry paradigm, i.e., substitution of organic solvents, application of nontoxic ingredients and minimal quantities of wastes formed in their synthesis and usage. In this work, the advantages of deep eutectic solvents were shown in the development of electrochemical sensor for epinephrine determination. Polythionine molecularly imprinted with epinephrine (PTNMIP) was electrodeposited from natural deep eutectic solvent (NADES) consisted of citric acid, glucose, and water in 1:1:6 molar ratio and tested with standard solutions of epinephrine, pharmaceutical preparations, and artificial samples of biological liquids. Only one drop (100 µL) of the monomer dissolved in NADES was applied for sensor preparation on the platform of screen-printed carbon electrode. Electropolymerization was performed by multiple scanning of the potential. The formation of molecular imprints was confirmed by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). After the template removal, the charge transfer resistance of the surface layer depended on the epinephrine concentration in the range from 100 nM to 316 µM (limit of detection 50 nM). Selectivity of the signal was confirmed against serotonin and norepinephrine commonly present in biological liquids. Sensor was successfully tested for the determination of epinephrine in spiked solutions mimicking influence of the plasma electrolytes, serum proteins, and in real saliva samples. The recoveries calculated for 10 μM epinephrine ranged from 98.3 to 102.6%. Insignificant influence of the additives and stabilizers present in medications was eliminated by sample dilution. Impedimetric sensor developed showed good opportunities for further application in clinical diagnostics, pharmacokinetics studies and medication manufacture control.

Development of a generalized pharmacokinetic model to characterize clinical pharmacokinetics of monomethyl auristatin E-based antibody-drug conjugates.

This study aims to develop a generalized pharmacokinetic (PK) model for monomethyl auristatin E (MMAE)-based antibody-drug conjugates (ADCs) that can simultaneously capture the PK of multiple ADC analytes commonly measured in the clinic. A comprehensive literature review was conducted to collect PK data on MMAE-based ADCs from clinical trials. From each study, PK profiles of total antibody, the ADC, conjugated MMAE, and unconjugated MMAE, were extracted. These data were pooled and dose-normalized to evaluate the generalizability of PK across various ADCs and dose levels. Upon confirming PK generalizability, a generalized PK model for MMAE-based ADCs was developed using the entire dataset. Furthermore, exposure metrics ( and AUC) reported across the range of doses were combined to establish linear relationships between dose and exposure metrics for MMAE-based ADCs. A total of 109 PK profiles from 18 distinct MMAE-based ADCs were gathered. The dose-normalized PK profiles supported the generalizability of PK for MMAE-based ADCs. A generalized PK model was developed, which enabled capturing the PK data for 4 ADC analytes across all collected MMAE-based ADCs. A linear relationship between dose and PK exposure metrics was established, enabling the prediction of typical exposure values across different doses for MMAE-based ADCs. This study comprehensively analysed clinical PK data from different valine-citrulline (vc)-MMAE-based ADCs. The generalized PK model developed here serves as an important tool for a priori prediction of the PK for multiple ADC analytes in clinical settings and lays the foundation for establishing generalized exposure-response and exposure-toxicity correlations for MMAE-based ADCs.

Simulated cost-effectiveness of a novel precision-guided dosing strategy in adult patients with Crohn's disease initiating infliximab maintenance therapy.

Patients with Crohn's disease (CD) who lose response to biologics experience reduced quality of life (QoL) and costly hospitalizations. Precision-guided dosing (PGD) provides a comprehensive pharmacokinetic (PK) profile that allows for biologic dosing to be personalized. We analyzed the cost-effectiveness of infliximab (IFX) PGD relative to two other dose intensification strategies (DIS). We developed a hybrid (Markov and decision tree) model of patients with CD who had a clinical response to IFX induction. The analysis had a US payer perspective, a base case time horizon of 5 years, and a 4-week cycle length. There were three IFX dosing comparators: PGD; dose intensification based on symptoms, inflammatory markers, and trough IFX concentration (DIS1); and dose intensification based on symptoms alone (DIS2). Patients that failed IFX initiated ustekinumab, followed by vedolizumab, and conventional therapy. Transition probabilities for IFX were estimated from real-world clinical PK data and interventional clinical trial patient-level data. All other transition probabilities were derived from published randomized clinical trials and cost-effectiveness analyses. Utility values were sourced from previous health technology assessments. Direct costs included biologic acquisition and infusion, surgeries and procedures, conventional therapy, and lab testing. The primary outcomes were incremental cost-effectiveness ratios (ICERs). The robustness of results was assessed via one-way sensitivity, scenario, and probabilistic sensitivity analyses (PSA). PGD was the cost-effective IFX dosing strategy with an ICER of 122,932 $ per quality-adjusted life year (QALY) relative to DIS1 and dominating DIS2. PGD had the lowest percentage (1.1%) of patients requiring a new biologic through 5 years (8.9% and 74.4% for DIS1 and DIS2, respectively). One-way sensitivity analysis demonstrated that the cost-effectiveness of PGD was most sensitive to the time between IFX doses. PSA demonstrated that joint parameter uncertainty had moderate impact on some results. PGD provides clinical and QoL benefits by maintaining remission and avoiding IFX failure; it is the most cost-effective under conservative assumptions.

Modeling the subcutaneous pharmacokinetics of antibodies co-administered with rHuPH20.

Predicting the subcutaneous (SC) pharmacokinetics (PK) of antibodies in humans is challenging, with clinical data currently being the only reliable data source for modeling SC absorption and bioavailability. Recombinant human hyaluronidase PH20 (rHuPH20) is an enzyme that facilitates SC delivery of high-dose, high-volume therapeutics. Numerous monoclonal antibodies have been co-administered SC with rHuPH20 in a clinical setting, establishing an extensive PK database. The goal of this work is to demonstrate how aggregated clinical data can be leveraged in a universal modeling framework for characterizing SC antibody PK, resulting in parameterization that can be used in predictive simulations of new antibodies. Data for 10 individual antibodies co-administered SC with rHuPH20 were obtained from publicly available sources. PK modeling of each antibody was conducted using the same model structure, but uniquely parameterized. The model structure consisted of a two-compartment model to capture linear kinetics, plus a target-binding mechanism to accommodate nonlinear kinetics driven by antibody-target complex formation and elimination. The clinical PK profiles for all antibodies were accurately described using the universal modeling framework. The SC PK parameters of absorption and bioavailability were consistent across the range of antibody and target properties evaluated. SC administration with rHuPH20 yielded a 30% increase in absorption rate on average and similar or better bioavailability. These parameter values can serve as initial conditions for model-based PK predictions for new antibodies co-administered SC with rHuPH20 to enable evaluation of optimal SC dose and schedule regimens prior to and during clinical development.

Clinical pharmacokinetics of leriglitazone and a translational approach using PBPK modeling to guide the selection of the starting dose in children.

Leriglitazone is a unique peroxisome proliferator-activated receptor-gamma (PPARγ) agonist that crosses the blood-brain barrier in humans and clinical trials have shown evidence of efficacy in neurodegenerative diseases. At clinical doses which are well-tolerated, leriglitazone reaches the target central nervous system (CNS) concentrations that are needed for PPARγ engagement and efficacy; PPARγ engagement is also supported by clinical and anti-inflammatory biomarker changes in the Cerebrospinal fluid in the CNS. Plasma pharmacokinetics (PK) of leriglitazone were determined in a phase 1 study in male healthy volunteers comprising a single ascending dose (SAD) and a multiple ascending dose (MAD) at oral doses of 30, 90, and 270 mg and 135 and 270 mg, respectively. Leriglitazone was rapidly absorbed with no food effect on overall exposure and showed a linear PK profile with dose-exposure correlation. A physiologically based pharmacokinetic (PBPK) model was developed for leriglitazone based on phase 1 data (SAD part) and incorporated CYP3A4 (fmCYP3A4 = 24%) and CYP2C8-mediated (fmCYP2C8 = 45%) metabolism, as well as biliary clearance (feBIL = 19.5%) derived from invitro data, and was verified by comparing the observed versus predicted concentration-time profiles from the MAD part. The PBPK model was prospectively applied to predict the starting pediatric doses and was preliminarily verified with data from five pediatric patients.

Abstract 6424: A patient centric full spectrum flow cytometry assay for comprehensive phenotyping of CAR T cells in clinical trials

Abstract Purpose While there is a strong desire to fully understand next generation CAR-T product characteristics in clinical trials, limited amounts of blood specimens are available as the enrolled patients are very sick and lymphodepleted. To address this high unmet need, we developed a single tube 20-color full spectrum flow cytometry assay for an in-depth characterization of CAR-T cells that support fulfilment of five key clinical trial endpoints, namely, manufacturing success (fitness and memory state), pharmacokinetics, response or resistance (ICIs), efficacy (gross tumor burden) and safety (B cell regeneration) for use across a broad range of CAR-T therapies and clinical indications. Study Design: The single tube 20-parameter full spectrum flow cytometry (FC) assay was designed to include CD45, HLA-DR, CD3, CD4, CD8, CD56 as backbone markers, CD45RA, CCR7, CD95, CD25 and CD127 antibodies allowed for the identification of all major subsets of CD4 and CD8 T cells. CXCR3, CD38, PD1, LAG3, and TIM3 were used for identification of activation/exhaustion phenotypes, while CD20 and HLA-DR were useful for identification of B cells and monocytes respectively. Additionally, we left two parameters (PE and AF647) open for customized CAR-T detection reagents or other customized markers. This assay was developed using Cytek® Northern Lights™ and frozen PBMCs. Results This robust 20-color full spectrum FC assay allowed a thorough analysis of the major T cell populations cells. FMO (Fluorescence-Minus-One) control studies confirmed the specificity of the antibodies and of the panel in identifying Naïve, EMRA, CM, EM, Th17, T stem cell memory and regulatory T cells with minimum background on all parameters. This method showed to be highly reproducible and can be adapted for use with many CAR-T detection reagents. Conclusion In summary, we developed a robust 20-parameter multiparameter full spectrum flow cytometry assay focused on different populations of T cells in a single tube. The inclusion of drop ins for prospective CAR-T cell detection reagents allows for easy integration of future advances in CAR-T cell research. This universal panel shows great potential for usage across CAR-T clinical trials, as it serves as a valuable tool understand product fitness, PK, biomarker monitoring and disease burden simultaneously. Citation Format: Keegan Vaughan, Selvam Muthusamy, Coral Zhao, Austin Carbajal, Charlie Fu, Naveen Dakappagari, Zeni Alfonso. A patient centric full spectrum flow cytometry assay for comprehensive phenotyping of CAR T cells in clinical trials [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6424.