Plasma AUC Research Articles

EXTH-56. CSF PENETRATION COMPARISON OF TWO ORAL FORMULATIONS OF APL-101 IN A PRE-CLINICAL NON-HUMAN PRIMATE MODEL

Abstract Vebreltinib (APL-101) is a potent c-Met inhibitor which has shown efficacy in murine pre-clinical models and is under clinical trial evaluation for several cancer types, including adult high-grade glioma. The capsule formulation (APL-101-Cap) was reformulated as a pill (APL-101-Pill) with the expectation of increasing bioavailability. We determined and compared the plasma pharmacokinetics (PK) and cerebrospinal fluid (CSF) penetration of APL-101-Cap and APL-101-Pill in a non-human primate (NHP) model. METHODS: Seven animals, previously developed as serial CSF access models, were utilized across all studies. One NHP was studied with both formulations. Both formulations were administered orally as a single drug/single dose in serial studies, followed by serial plasma and CSF sample collections from 0-96 hours. Dosages: APL-101-Cap 3.25 mg/kg (n = 3) or 6.5 mg/kg (n = 4) and APL-101-Pill 5 mg/kg (n = 4). The resulting plasma concentrations from each formulation were quantified by LC-MS/MS. PK parameters were calculated via noncompartmental methods, and results were analyzed to assess CNS penetration (AUCCSF:AUCPlasma) and compare formulations. RESULTS: Mean (range) for plasma and CSF PK exposure [AUCLAST (hr*ng/mL)] reported. APL-101-Cap plasma exposure, regardless of dose, was more variable than APL-101-Pill. APL-101-Pill had lower exposure in both plasma (AUC 1893.0 (841-2865)] and CSF [AUC 27.7 (5.0-65.0)] than APL-101-Cap regardless of dose [(3.25 mg/kg): plasma AUC 9621.0 (1331-23132) and CSF AUC 688.0 (24-1352); 6.5 mg/kg: plasma AUC 6208.0 (1424-19800) and CSF AUC 606.0 (34-1179)]. CNS penetrance was higher with APL-101-Cap (3.2% [0.5-5.8%] at 3.25mg/kg; 4.2% (2.4-6%) at 6.5 mg/kg), but also more variable when compared to APL-101-Pill (1.2% [0.6-2.3%]). For APL-101-Cap, one animal at 3.25 mg/kg and two animals at 6.25 mg/kg had undetectable CSF concentrations. CONCLUSION: In this NHP model, single-dose oral administration of APL-101-Pill resulted in lower, but less variable plasma and CSF exposure compared to APL-101-Cap. APL-101-Cap CSF exposure was unaffected by dose escalation.

Oral Drug Absorption and Drug Disposition in Critically Ill Cardiac Patients.

(1) Background: In critically ill cardiac patients, parenteral and enteral food and drug administration routes may be used. However, it is not well known how drug absorption and metabolism are altered in this group of adult patients. Here, we analyze drug absorption and metabolism in patients after cardiogenic shock using the pharmacokinetics of therapeutically indicated esomeprazole. (2) Methods: The pharmacokinetics of esomeprazole were analyzed in a consecutive series of patients with cardiogenic shock and controls before and after elective cardiac surgery. Esomeprazole was administered orally or with a nasogastric tube and once as an intravenous infusion. (3) Results: The maximum plasma concentration and AUC of esomeprazole were, on average, only half in critically ill patients compared with controls (p < 0.005) and remained lower even seven days later. Interestingly, esomeprazole absorption was also markedly compromised on day 1 after elective surgery. The metabolites of esomeprazole showed a high variability between patients. The esomeprazole sulfone/esomeprazole ratio reflecting CYP3A4 activity was significantly lower in critically ill patients even up to day 7, and this ratio was negatively correlated with CRP values (p = 0.002). The 5'-OH-esomeprazole and 5-O-desmethyl-esomeprazol ratios reflecting CYP2C19 activity did not differ significantly between critically ill and control patients. (4) Conclusions: Gastrointestinal drug absorption can be significantly reduced in critically ill cardiac patients compared with elective patients with stable cardiovascular disease. The decrease in bioavailability indicates that, under these conditions, any vital medication should be administered intravenously to maintain high levels of medications. After shock, hepatic metabolism via the CYP3A4 enzyme may be reduced.

CYP Inhibition and Low-Dose Dasatinib for Chronic Myeloid Leukemia: Preliminary Results of a Promising, Cost-Effective Treatment Option

Introduction The standard treatment for newly diagnosed (ND)-CML is tyrosine kinase inhibitors (TKIs) such as dasatinib. However, the cost of treatment with these drugs can be prohibitively high. The CYP inhibition strategy involves intentionally inhibiting a specific enzyme, in this case CYP3A4, to increase plasma concentration of dasatinib and reduce the required dose from 100mg to 25mg daily. Patients and methods Five consecutive patients older than 18 years, with ND-CML in chronic phase and Eastern Cooperative Oncology Group (ECOG) of 0-2.The diagnosis and classification of CML followed the ESMO guidelines. After diagnostic confirmation, patients continuously received half pill of dasatinib (25mg orally daily) and a strong CYP3A4 inhibitor (ketoconazole, 200mg orally twice daily). Patients were monitored weekly during the first month and then monthly after that. The response to treatment was established according to the ESMO guidelines. Statistical analysis We examined the distribution of variables using the Shapiro-Wilk test, and descriptive analyses were conducted for demographic and clinical characteristics. The proportion of hematological and non-hematological side effects and the proportion of hematological response were obtained. To demonstrate the effect of dasatinib on hematological cells, we constructed a line plot showing the values of hemoglobin, leukocytes, and platelets in each visit. We compared basal hemoglobin, leukocytes, and platelets vs. follow-up counts at each visit with the Kruskal-Wallis test Results The median age of the patients was 42 years. All patients had a median ECOG score of 0. Three patients (60%) presented with thrombocytosis, three (60%) with splenomegaly, and two patients (40%) had B symptoms. Basal median (range) hemoglobin, leukocytes, and platelets counts were 9.9 g/dL , 272×10 9/L and 451×10 9/L, respectively. Three patients (60%) had low-risk CML, and two patients (40%) had high-risk disease, with a median EUTOS score of 71 points. Dasatinib treatment was initiated within a median of 9 days from diagnosis. In the first 28 days of treatment, median leukocytes and platelets were significantly reduced compared to baseline, with a reduction in leukocytes of 93.7% (125×10 9/L vs. 7.9×10 9/L, p=0.005) and in platelets of 64.6% (407×10 9/L, vs. 144×10 9/L, p=0.027). Hemoglobin levels significantly increased by the second month of treatment, with an increase of 26.4% from baseline (10.2 g/dL vs. 12.9 g/dL, p=0.023). All patients (100%) achieved major hematological response within a median of 22 days. Patient number 1 achieved the 3-month and 6-month treatment goals with 6.4% and &amp;lt;1% reduction in BCR-ABL transcript levels, respectively. After 3 months of treatment, 60% of patients achieved the BCR/ABL1 transcript level on the IS &amp;lt;10%, which is the optimal response according to guidelines, in the rest of the patients the time of evaluation has not been reached. Mild and self-limited adverse events were reported in 40% of patients at some point in their treatment. Non-hematological toxicity occurred in one patient (20%) with nausea and galactorrhea due to ketoconazole. Hematological toxicity occurred in (20%) of patients; the platelet count returned to normal after suspending ketoconazole for one week. No serious adverse events were reported. Conclusion Apart from this preliminary study, there is currently no evidence supporting the intentional use of CYP inhibition to reduce the dosage and cost of dasatinib for patients with ND-CML. Dasatinib is primarily metabolized using the CYP3A4 isoenzyme, and studies have shown that ketoconazole, an accessible antifungal, can strongly inhibit CYP3A4, increase dasatinib's plasma concentration and AUC by 5-fold and 385%, respectively, and allow for a reduction in dosage while maintaining therapeutic efficacy. The CYP inhibition strategy can decrease the cost of dasatinib to a point where it is cheaper than full-dose imatinib -the cheapest TKI- and represent a treatment option for patients who cannot afford full-dose dasatinib in low income countries. The CYP inhibition strategy can be of added value to the lower effective dose concept and give rise to ultra-low-dose schemes. This strategy could significantly increase dasatinib accessibility in many countries by reducing costs from $1,343.7 to $40.3-$100.8 monthly

Predicting Maternal and Infant Tetrahydrocannabinol Exposure in Lactating Cannabis Users: A Physiologically Based Pharmacokinetic Modeling Approach.

A knowledge gap exists in infant tetrahydrocannabinol (THC) data to guide breastfeeding recommendations for mothers who use cannabis. In the present study, a paired lactation and infant physiologically based pharmacokinetic (PBPK) model was developed and verified. The verified model was used to simulate one hundred virtual lactating mothers (mean age: 28 years, body weight: 78 kg) who smoked 0.32 g of cannabis containing 14.14% THC, either once or multiple times. The simulated breastfeeding conditions included one-hour post smoking and subsequently every three hours. The mean peak concentration (Cmax) and area under the concentration-time curve (AUC(0-24 h)) for breastmilk were higher than in plasma (Cmax: 155 vs. 69.9 ng/mL; AUC(0-24 h): 924.9 vs. 273.4 ng·hr/mL) with a milk-to-plasma AUC ratio of 3.3. The predicted relative infant dose ranged from 0.34% to 0.88% for infants consuming THC-containing breastmilk between birth and 12 months. However, the mother-to-infant plasma AUC(0-24 h) ratio increased up to three-fold (3.4-3.6) with increased maternal cannabis smoking up to six times. Our study demonstrated the successful development and application of a lactation and infant PBPK model for exploring THC exposure in infants, and the results can potentially inform breastfeeding recommendations.

Preclinical safety, toxicokinetics and metabolism of BIIB131, a novel prothrombolytic agent for acute stroke

BIIB131, a small molecule, is currently in Phase 2 for the treatment of acute ischemic stroke. Safety and metabolism of BIIB131 were evaluated following intravenous administration to rats and monkeys. Exposure increased dose-proportionally in rats up to 60 mg/kg and more than dose-proportionally in monkeys at greater than 10 mg/kg accompanied by prolonged half-life and safety findings. The BIIB131 was poorly metabolized in microsomes with no inhibition of CYPs. BIIB131-glucuronide, formed by UGT1A1, accounted for 21.5% metabolism in human hepatocytes and 28–40% in rat bile. In rats, excretion was primarily via the bile. BIIB131 inhibited the hERG and Nav1.5 cardiac channels by 39% but showed no effect on cardiovascular parameters in monkeys. Toxicology findings were limited to reversable hematuria, changes in urinary parameters and local effects. A MTD of 30 mg/kg was established in monkeys, the most sensitive species, at total plasma Cmax and AUC of 6- and 14-fold, respectively, greater than the NOAEL. The Phase 1 study started with intravenous 0.05 mg/kg and ascended to 6.0 mg/kg which corresponded to safety margins of 147- to 0.9-fold (for Cmax) within the linear drug exposure. Thus, the preclinical profile of BIIB131 has been appropriately characterized and supports its further clinical development.

Pharmacokinetics of the KRASG12C inhibitor adagrasib is limited by CYP3A and ABCB1, and influenced by binding to mouse plasma carboxylesterase 1c

Adagrasib (Krazati™) is the second FDA-approved specific KRASG12C inhibitor for non-small cell lung cancer (NSCLC) patients harboring this mutation. The impact of the drug efflux transporters ABCB1 and ABCG2, and the drug-metabolizing enzymes CYP3A and carboxylesterase 1 (CES1) on the pharmacokinetics of oral adagrasib were studied using genetically modified mouse models. Adagrasib was potently transported by human ABCB1 and modestly by mouse Abcg2 in vitro. In Abcb1a/b-/- and Abcb1a/b;Abcg2-/- mice, the brain-to-plasma ratios were enhanced by 33- and 55-fold, respectively, compared to wild-type mice, whereas ratios in Abcg2-/- mice remained unchanged. The influence of ABC transporters was completely reversed by coadministration of the dual ABCB1/ABCG2 inhibitor elacridar, increasing the brain penetration in wild-type mice by 41-fold while no signs of acute CNS toxicity were observed. Tumor ABCB1 overexpression may thus confer adagrasib resistance. Whereas the ABC transporters did not affect adagrasib plasma exposure, CYP3A and Ces1 strongly impacted its apparent oral availability. The plasma AUC0–8 h was significantly enhanced by 2.3-fold in Cyp3a-/- compared to wild-type mice, and subsequently 4.3-fold reduced in transgenic CYP3A4 mice, indicating substantial CYP3A-mediated metabolism. Adagrasib plasma exposure was strongly reduced in Ces1-/- compared to wild-type mice, but tissue exposure was slightly increased, suggesting that adagrasib binds to plasma Ces1c in mice and is perhaps metabolized by Ces1. This binding could complicate interpretation of mouse studies, especially since humans lack circulating CES1 enzyme(s). Our results may be useful to further optimize the clinical safety and efficacy of adagrasib, and give more insight into potential drug-drug interactions risks.

Development of a Minimalistic Physiologically Based Pharmacokinetic (mPBPK) Model for the Preclinical Development of Spectinamide Antibiotics.

Spectinamides 1599 and 1810 are lead spectinamide compounds currently under preclinical development to treat multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis. These compounds have previously been tested at various combinations of dose level, dosing frequency, and route of administration in mouse models of Mycobacterium tuberculosis (Mtb) infection and in healthy animals. Physiologically based pharmacokinetic (PBPK) modeling allows the prediction of the pharmacokinetics of candidate drugs in organs/tissues of interest and extrapolation of their disposition across different species. Here, we have built, qualified, and refined a minimalistic PBPK model that can describe and predict the pharmacokinetics of spectinamides in various tissues, especially those relevant to Mtb infection. The model was expanded and qualified for multiple dose levels, dosing regimens, routes of administration, and various species. The model predictions in mice (healthy and infected) and rats were in reasonable agreement with experimental data, and all predicted AUCs in plasma and tissues met the two-fold acceptance criteria relative to observations. To further explore the distribution of spectinamide 1599 within granuloma substructures as encountered in tuberculosis, we utilized the Simcyp granuloma model combined with model predictions in our PBPK model. Simulation results suggest substantial exposure in all lesion substructures, with particularly high exposure in the rim area and macrophages. The developed model may be leveraged as an effective tool in identifying optimal dose levels and dosing regimens of spectinamides for further preclinical and clinical development.

Torsemide increases arsenic concentrations by inhibition of multidrug resistance protein 4 in arsenic trioxide treated acute promyelocytic leukemia patients

Torsemide is commonly used to relieve edema during the treatment of acute promyelocytic leukemia (APL) with arsenic trioxide (ATO). We explored the effect of torsemide on the plasma concentrations of inorganic arsenic (iAs), monomethylarsonic acid (MMAV) and dimethyarsinic acid (DMAV) in APL patients treated with ATO and clarified its molecular mechanism in rats and cells. The study included 146 APL patients treated with ATO. 60（41.1 %) of these 146 patients were co-administered with torsemide. The treatment of torsemide increased plasma concentrations of iAs (P < 0.05) and DMAV (P < 0.05) in APL patients. The single co-administration of ATO and torsemide in rats significantly increased the plasma concentrations and AUC(0−t) of iAs (P < 0.05) and MMAV (P < 0.05), decreased the urinary excretion rates and the urine concentrations of iAs (P < 0.05) and DMAV (P < 0.05), and enhanced iAs (P < 0.05) and MMAV (P < 0.05) concentrations in the kidneys of rats. In addition, torsemide decreased the expression of multidrug resistance protein 4 (MRP4) in rat kidneys after 7 days of continuous co-administration (P < 0.05). We also treated MRP4-overexpressing HEK293T cells with ATO and different concentrations of torsemide. Torsemide markedly increased the concentrations of iAs, MMAV and DMAV by inhibiting MRP4 compared with ATO alone (P < 0.05). In conclusion, torsemide increased the plasma concentrations of arsenic metabolites in APL patients treated with ATO by inhibiting the transporter MRP4 in a dose-dependent manner.

Individual Components of Polymyxin B Modeled via Population Pharmacokinetics to Design Humanized Dosage Regimens for a Bloodstream and Lung Infection Model in Immune-Competent Mice.

Polymyxin B is a "last-line-of-defense" antibiotic approved in the 1960s. However, the population pharmacokinetics (PK) of its four main components has not been reported in infected mice. We aimed to determine the PK of polymyxin B1, B1-Ile, B2, and B3 in a murine bloodstream and lung infection model of Acinetobacter baumannii and develop humanized dosage regimens. A linear 1-compartment model, plus an epithelial lining fluid (ELF) compartment for the lung model, best described the PK. Clearance and volume of distribution were similar among the four components. The bioavailability fractions were 72.6% for polymyxin B1, 12.0% for B1-Ile, 11.5% for B2, and 3.81% for B3 for the lung model and were similar for the bloodstream model. While the volume of distribution was comparable between both models (17.3 mL for the lung and ~27 mL for the bloodstream model), clearance was considerably smaller for the lung (2.85 mL/h) compared to that of the bloodstream model (5.59 mL/h). The total drug exposure (AUC) in ELF was high due to the saturable binding of polymyxin B presumably to bacterial lipopolysaccharides. However, the modeled unbound AUC in ELF was ~16.7% compared to the total drug AUC in plasma. The long elimination half-life (~4 h) of polymyxin B enabled humanized dosage regimens with every 12 h dosing in mice. Daily doses that optimally matched the range of drug concentrations observed in patients were 21 mg/kg for the bloodstream and 13 mg/kg for the lung model. These dosage regimens and population PK models support translational studies for polymyxin B at clinically relevant drug exposures.

Abstract 514: Novel potent azetidine-based inhibitors bind irreversibly to Stat3 DNA-binding domain (DBD) and are efficacious against tumor growth in mice

Abstract Unlike classical Signal transducer and activator of transcription (Stat) signaling, which is transient in non-transformed cells, the aberrant activation of the family member, Stat3, occurs in malignant transformation and is implicated in breast, ovarian and many other human cancers. Thus, Stat3 remains a validated and important target for the discovery of novel anticancer drugs. Despite this, the discovery and development of potent Stat3 small molecule inhibitors has proven to be a significant challenge, and no drug is available yet in the market. We have discovered novel Stat3 irreversible azetidine inhibitors with unprecedent submicromolar potency through systematic medicinal chemistry structure activity relationship (SAR). Mechanism of action of most potent azetidine inhibitors depend on whether they are salicylic acids or not, i.e., salicylic acids preferably bind irreversibly to Stat3 Cys426 site in the DNA-binding domain (DBD), and non-salicylic acids, e.g., current lead H182, bind to Stat3 Cys468 DBD site. As expected, the inhibition of Stat3 DNA-binding activity was time dependent, with IC50 in the range of 0.27-0.87 µM at one hour incubation with active Stat3. On the other hand, azetidine salicylic acids also bind to the SH2 domain, although reversibly and at much weaker affinity, as determined in fluorescent polarization (FP) assay, with IC50 of 10-16 µM at one hour incubation, while non-salicylic acids, e.g., lead H182, present no binding affinity up to 600 µM for the SH2 domain. Despite that H182 does not bind to SH2 domain, it still inhibits its phosphorylation. Though lead compound H182 presents significant mouse in vivo efficacy, mouse in vivo pharmacokinetics shows very low plasma AUC, which correlates with quite high mouse in vitro hepatocyte CLint of 138 µL/min/106 cells; however, human in vitro hepatocyte assay gives much better results and is in the middle stability range (CLint of 14.6 µL/min/106 cells). The in vivo PK in other species, e.g., rat, is being determined. H182 represents a plausible molecule for further development. Citation Format: Yue Chen, Ning Zhai, Yinsong Zhu, Peibin Yue, Nagendra Verma, Christine Brotherton-Pleiss, Wenzhen Fu, Kayo Nakamura, Weiliang Chen, Marcus Tius, Francisco J. Lopez-Tapia, James Turkson. Novel potent azetidine-based inhibitors bind irreversibly to Stat3 DNA-binding domain (DBD) and are efficacious against tumor growth in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 514.

Abstract 3109: HZ-R078: A tumor-enriched STAT3 degrader for treating T-cell lymphoma in pre-clinical models

Abstract Background: The Janus kinase/Signal transducer and activator of transcription (JAK-STAT) pathway is one of the core cancer pathways that integrates signals from cytokines, hormones and growth factors to induce or repress gene expression in cells. The pathway consists of four JAK kinases and seven STAT transcription factors (STAT1, STAT2, STAT3, STAT4, STAT5A, STAT5B and STAT6). STAT3 is the best-studied family member of the JAK-STAT pathway in cancer and is a known oncogene in various types of tumor. Besides its important role in cancer development, STAT3 is also essential in normal tissues. Completely blockage of STAT3 can lead to serious side effects. How to balance the efficacy and adverse effect is a critical issue in development of STAT3 inhibitor. HZ-R078 is a novel selective STAT3 degrader which exhibits long-lasting STAT3 degradation effect in tumor tissue, while the clearance in plasma and other organs are high. Based on this unique PK character, HZ-R078 shows potent efficacy and high safety. Experimental Design: In-vitro STAT3 degradation was evaluated in various caner cell lines. In-vitro wash-out assay was conducted in a one-week cycle. In this wash-out assay, SU-DHL1 cells in different groups were treated with HZ-R078 at the concentration of DC95 for 24, 48, 72h firstly, then the drug was washed out, the cell growth and STAT3 protein level were evaluated daily in next 6, 5, 4 days recovery-period respectively. PK/PD study was performed in SU-DHL1 xenograft model in a 168 h-period. The drug concentration was determined in plasma and tumor tissue at different time points, the STAT3 degradation rate was also evaluated in corresponding tumor tissues. In-vivo anti-tumor effect was determined in two T-cell lymphoma models. Results: HZ-R078 can completely degrade STAT3 in various types of cell, the DC50 values ranges from 5 to 150 nano-molar. In wash-out assay, we demonstrated that maintain the drug concentration above DC95 for more than 48 hours can completely suppress the STAT3 level and irreversibly inhibit the cell growth in the following recovery-period in T-cell lymphoma cell lines. This important finding was further validated in PK/PD study. In PK/PD study, we also find that HZ-R078 has much lower clearance in tumor tissue than plasma and other organs. The ratio of plasma AUC to tumor AUC is approximate to 1. In in-vivo anti-tumor evaluation, HZ-R078 can significantly suppress the growth of tumor in SU-DHL1 and Karpass299 models in a weekly administration. In pre-clinical safety study, HZ-R078 exhibits higher MTD dose in Rats. Conclusion: HZ-R078 is a selective and potent STAT3 degrader which has tumor-enriched distribution character. The pre-clinical efficacy and safety study support its further development in clinical stage for T-cell lymphoma therapy. Citation Format: Yizhe Wu, Xinxin Jin, Xinglu Zhou. HZ-R078: A tumor-enriched STAT3 degrader for treating T-cell lymphoma in pre-clinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3109.

Overcoming drug resistance with a docetaxel and disulfiram loaded pH-sensitive nanoparticle.

Previous studies have demonstrated that breast cancer cells deploy a myriad array of strategies to thwart the activity of anticancer drugs like docetaxel (DTX), including acquired drug resistance due to overexpression of drug-efflux pumps like P-glycoprotein (P-gp) and innate drug resistance by cancer stem cells (CSCs). As disulfiram (DSF) can inhibit both P-gp and CSCs, we hypothesized that co-treatment of DTX and DSF could sensitize the drug-resistant breast cancer cells. To deliver a fixed dose ratio of DTX and DSF targeted to the tumor, a tumor extracellular pH-responsive nanoparticle (NP) was developed using a histidine-conjugated star-shaped PLGA with TPGS surface decoration ([DD]NpH-T). By releasing the encapsulated drugs in the tumor microenvironment, pH-sensitive NPs can overcome the tumor stroma-based resistance against nanomedicines. In in-vitro studies, [DD]NpH-T exhibited increased drug release at pH 6.4, improved penetration in a 3D tumor spheroid, reduced serum protein adsorption, and enhanced cytotoxic efficacy against both innate and acquired DTX-resistant breast cancer cells. In in-vivo studies, a significant increase in plasma AUC and tumor drug delivery was observed with [DD]NpH-T, which resulted in an enhanced in-vivo anti-tumor efficacy against a mouse orthotopic breast cancer, with a significantly increased intratumoral ROS and apoptosis, while decreasing P-gp expression and prevention of lung metastasis. Altogether, the current study demonstrated that the DTX and DSF combination could effectively target multiple drug-resistance pathways in-vitro, and the in-vivo delivery of this drug combination using TPGS-decorated pH-sensitive NPs could increase tumor accumulation, resulting in improved anti-tumor efficacy.

Screening for Differences in Early Exposure in the Fasted State with in Vitro Methodologies can be Challenging: Experience with the BioGIT System

The Biorelevant Gastrointestinal Transfer (BioGIT) system is a useful screening tool for assessing the impact of dose and/or formulation on early exposure after administration of immediate release or enabling drug products with a glass of water in the fasted state. The objective of this study was to investigate potential limitations. BioGIT experiments were performed with five low solubility active pharmaceutical ingredients with weakly alkaline characteristics: mebendazole (tablet and chewable tablet), Compound E (aqueous solutions, three doses), pazopanib-HCl (Votrient™ tablet, crushed Votrient™ tablet and aqueous suspension), Compound B-diHCl (hard gelatin capsule, three doses) and Compound C (hard gelatin capsule containing nanosized drug and hard gelatin capsule containing micronized drug). For all formulation or dose comparisons the ratio of mean BioGIT AUC0–50 min values was not predictive of the ratio of mean plasma AUC0–60 min values which became available after completion of BioGIT experiments. BioGIT experimental conditions have not been designed to simulate the gastrointestinal drug transfer process after administration of chewable tablets or aqueous solutions, therefore, BioGIT may not be useful for the assessment of intraluminal performance early after administration of such drug products. Also, based on this study, BioGIT may not be useful in investigating the impact of dose and/or formulation on early exposure when the dose is not administered with a glass of water to fasted healthy individuals or when BioGIT data are highly variable. Finally, the rapid dissolution of nanocrystals after administration of low solubility weak bases may require adjustment of the pH in the gastric compartment of BioGIT to slightly higher pH values. Limitations identified in this study for the BioGIT system may be also relevant to other in vitro systems proposed for similar evaluations.

Usefulness of the BioGIT system in screening for differences in early exposure in the fasted state on an a priori basis

The objective of the present study was to confirm the usefulness of BioGIT data in the evaluation of the impact of dose and/or formulation on early exposure after oral administration of immediate release or enabling products of low solubility active pharmaceutical ingredients (APIs) with a glass of water in the fasted state. BioGIT experiments were performed with four APIs: Compound Α (tablet, three dose levels), Compound E (capsule PiC1, capsule PiC2 and tablet), fenofibrate (Lipidil® capsule and Lipidil 145 ONE® tablet) and Compound F (HP-β-CD aqueous solution and tablet). Based on mean plasma AUC0-60min values which became available after completion of the BioGIT experiments, mean BioGIT AUC0-50min values were useful for the evaluation of the impact of dose and/or formulation on early exposure. The log-transformed ratios of mean BioGIT AUC0-50min values for two doses and/or two formulations estimated in this study and in a recent study for two diclofenac potassium products (Cataflam® tablet and Voltfast® sachet, same dose) vs. the corresponding log-transformed ratios of mean plasma AUC0-60min values (n = 7 pairs of ratios), were included in a previously established correlation between log-transformed ratios of mean BioGIT AUC0–50min values and log-transformed ratios of plasma AUC0–60min values (n = 9 pairs of ratios). The correlation between log-transformed plasma AUC0–60min ratios vs. log-transformed BioGIT AUC0–50min ratios was confirmed (n = 16 pairs of ratios, R = 0.90). Compared with the previously established correlation the statistical characteristics were improved. Based on this study, the BioGIT system could be useful as a screening tool for assessing the impact of dose and/or formulation differences on early exposure, after administration of immediate release or enabling drug products of low solubility APIs with a glass of water in the fasted state, on an a priori basis.

Design, Characterization and Pharmacokinetic-Pharmacodynamic Evaluation of Poloxamer and Kappa-Carrageenan-Based Dual-Responsive In Situ Gel of Nebivolol for Treatment of Open-Angle Glaucoma.

This study developed a dual-responsive in situ gel of nebivolol (NEB), a selective β-adrenergic antagonist. The gel could achieve sustained concentrations in the aqueous humor to effectively treat glaucoma. The gel was prepared using a combination of poloxamers (Poloxamer-407 (P407) and Poloxamer-188 (P188)) and kappa-carrageenan (κCRG) as thermo-responsive and ion-sensitive polymers, respectively. Box-Behnken design (BBD) was used to optimize the effect of three critical formulation factors (concentration of P407, P188 and κCRG) on two critical response variables (sol-to-gel transition temperature of 33-35 °C and minimum solution state viscosity) of the in situ gel. A desirability function was employed to find the optimal concentrations of P407, P188 and κCRG that yielded a gel with the desired sol-to-gel transition temperature and solution state viscosity. An NEB-loaded gel was prepared using the optimized conditions and evaluated for in vitro drug release properties and ex vivo ocular irritation studies. Furthermore, ocular pharmacokinetic and pharmacodynamics studies were conducted in rabbits for the optimized formulation. The optimized NEB-loaded gel containing P407, P188 and κCRG had a sol-to-gel transition temperature of 34 °C and exhibited minimum viscosity (212 ± 2 cP at 25 °C). The optimized NEB-loaded gel sustained drug release with 86% drug release at the end of 24 h. The optimized formulation was well tolerated in the eye. Ocular pharmacokinetic studies revealed that the optimized in situ gel resulted in higher concentrations of NEB in aqueous humor compared to the NEB suspension. The aqueous humor Cmax of the optimized in situ gel (35.14 ± 2.25 ng/mL) was 1.2 fold higher than that of the NEB suspension (28.2 ± 3.1 ng/mL), while the AUC0-∞ of the optimized in situ gel (381.8 ± 18.32 ng/mL*h) was 2 fold higher than that of the NEB suspension (194.9 ± 12.17 ng/mL*h). The systemic exposure of NEB was significantly reduced for the optimized in situ gel, with a 2.7-fold reduction in the plasma Cmax and a 4.1-fold reduction in the plasma AUC0-∞ compared with the NEB suspension. The optimized gel produced a higher and sustained reduction in the intra-ocular pressure compared with the NEB suspension. The optimized gel was more effective in treating glaucoma than the NEB suspension due to its mucoadhesive properties, sustained drug release and reduced drug loss. Lower systemic exposure of the optimized gel indicates that the systemic side effects can be significantly reduced compared to the NEB suspension, particularly in the long-term management of glaucoma.

Benzo[a]pyrene toxicokinetics in humans following dietary supplementation with 3,3′-diindolylmethane (DIM) or Brussels sprouts

Utilizing the atto-zeptomole sensitivity of UPLC-accelerator mass spectrometry (UPLC-AMS), we previously demonstrated significant first-pass metabolism following escalating (25–250 ng) oral micro-dosing in humans of [14C]-benzo[a]pyrene ([14C]-BaP). The present study examines the potential for supplementation with Brussels sprouts (BS) or 3,3′-diindolylmethane (DIM) to alter plasma levels of [14C]-BaP and metabolites over a 48-h period following micro-dosing with 50 ng (5.4 nCi) [14C]-BaP. Volunteers were dosed with [14C]-BaP following fourteen days on a cruciferous vegetable restricted diet, or the same diet supplemented for seven days with 50 g of BS or 300 mg of BR-DIM® prior to dosing. BS or DIM reduced total [14C] recovered from plasma by 56–67% relative to non-intervention. Dietary supplementation with DIM markedly increased Tmax and reduced Cmax for [14C]-BaP indicative of slower absorption. Both dietary treatments significantly reduced Cmax values of four downstream BaP metabolites, consistent with delaying BaP absorption. Dietary treatments also appeared to reduce the T1/2 and the plasma AUC(0,∞) for Unknown Metabolite C, indicating some effect in accelerating clearance of this metabolite. Toxicokinetic constants for other metabolites followed the pattern for [14C]-BaP (metabolite profiles remained relatively consistent) and non-compartmental analysis did not indicate other significant alterations. Significant amounts of metabolites in plasma were at the bay region of [14C]-BaP irrespective of treatment. Although the number of subjects and large interindividual variation are limitations of this study, it represents the first human trial showing dietary intervention altering toxicokinetics of a defined dose of a known human carcinogen.

1727. Phase 1b Dose-ranging Study Demonstrates Tolerability and Pharmacokinetics (PK) of Oral Epetraborole at the Predicted Therapeutic Dosage for Mycobacterium avium Complex (MAC) Lung Disease

Abstract Background Epetraborole (EBO) — an orally available bacterial leucyl transfer RNA synthetase inhibitor with potent activity against nontuberculous mycobacteria — is under clinical development for treatment of MAC lung disease. We conducted a Phase 1b dose-ranging study of EBO tablets in healthy adult volunteers, to inform dose selection in the treatment of MAC lung disease. Methods In this double-blind, placebo-controlled trial, EBO or placebo tablets were administered (n=8/cohort, 3:1 randomization) at dosages of 250-1000 mg q24h or 500 mg or 1000 mg q48h for up to 28 days. Standard Ph1 clinical and laboratory evaluations and treatment-emergent adverse events (TEAEs) were assessed. Based on prior human studies using significantly higher EBO daily doses, gastrointestinal (GI) events and anemia were predetermined AEs of special interest (AESIs). Plasma concentrations of EBO were measured by validated LC-MS/MS methods. Plasma PK parameters were determined using non-compartmental methods. Results A total of 43 subjects were enrolled; the 1000 mg q24h cohort was terminated early due to local COVID restrictions. Overall, 80.6% EBO subjects and 83.3% placebo subjects experienced ≥1 TEAE, none of which was serious or severe (Table). Most TEAEs were mild in severity (90%), and the remainder were moderate (10%). No TEAE leading to withdrawal from study was reported. The most frequent types of TEAEs were GI events (48.4% EBO, 41.7% placebo subjects), the most common being mild nausea. Two subjects had premature discontinuation of EBO due to a TEAE (asymptomatic liver enzyme elevations in a 250 mg q24h subject and mild nausea in a 1000 mg q48h subject). One 1000mg q24h subject had a TEAE of anemia. No clinically significant findings or TEAEs were observed for physical examinations, ECGs, or urine laboratory tests. Plasma Cmax and AUC0-∞ of EBO increased in a linear, dose-proportional manner across cohorts. Tmax was observed at ∼1 h post dose; mean t1/2 ranged from 7.63 to 11.1 h. Conclusion Oral EBO administered for 28-day dosing was generally well tolerated at the predicted therapeutic dose (500mg q24h) Predictable PK characteristics facilitate its use in MAC lung disease Further evaluation in a Phase 2/3 treatment-refractory MAC lung disease study is planned Disclosures Paul B. Eckburg, MD, Paratek Pharmaceuticals, Inc.: Safety Review Board|Spero Therapeutics, Inc.: Advisor/Consultant Sanjay Chanda, PhD, AN2 Therapeutics: Stocks/Bonds George Talbot, MD, AN2 Therapeutics, Inc.: Advisor/Consultant|AN2 Therapeutics, Inc.: Co-founder Christopher M. Rubino, PharmD, Adagio Therapeutics: Grant/Research Support|Amplyx Pharmaceuticals, Inc: Grant/Research Support|AN2 Therapeutics: Grant/Research Support|Antabio SAS: Grant/Research Support|Arcutis Biotherapeutics, Inc: Grant/Research Support|B. Braun Medical Inc.: Grant/Research Support|Basilea Pharmaceutica: Grant/Research Support|Boston Pharmaceuticals: Grant/Research Support|Bravos Biosciences: Ownership Interest|Celdara Medical LLC: Grant/Research Support|Cidara Therapeutics Inc: Grant/Research Support|Cipla USA: Grant/Research Support|Crestone Inc: Grant/Research Support|CXC: Grant/Research Support|Debiopharm International SA: Grant/Research Support|Entasis Therapeutics: Grant/Research Support|Evopoint Biosciences Co.: Grant/Research Support|Fedora Pharmaceuticals: Grant/Research Support|GlaxoSmithKline: Grant/Research Support|Hoffmann-La Roche: Grant/Research Support|ICPD: Ownership Interest|ICPD Biosciences, LLC.: Ownership Interest|Insmed Inc.: Grant/Research Support|Iterum Therapeutics Limited: Grant/Research Support|Kaizen Bioscience, Co.: Grant/Research Support|KBP Biosciences USA: Grant/Research Support|Lassen Therapeutics: Grant/Research Support|Matinas Biopharma: Grant/Research Support|Meiji Seika Pharma Co., Ltd.: Grant/Research Support|Melinta Therapeutics: Grant/Research Support|Menarini Ricerche S.p.A: Grant/Research Support|Mutabilis: Grant/Research Support|Nabriva Therapeutics AG: Grant/Research Support|Novartis Pharmaceuticals Corp.: Grant/Research Support|Paratek Pharmaceuticals, Inc.: Grant/Research Support|PureTech Health: Grant/Research Support|Sfunga Therapeutics: Grant/Research Support|Spero Therapeutics,: Grant/Research Support|Suzhou Sinovent Pharmaceuticals Co.: Grant/Research Support|TauRx Therapeutics: Grant/Research Support|Tetraphase Pharmaceuticals: Grant/Research Support|tranScrip Partners: Grant/Research Support|Utility Therapeutics: Grant/Research Support|Valanbio Therapeutics, Inc.: Grant/Research Support|VenatoRx: Grant/Research Support|Wockhardt Bio AG: Grant/Research Support.

614. Pharmacodynamics (PD) of the Beta-Lactamase Inhibitor Xeruborbactam When Administered as the Oral Prodrug in Combination with Ceftibuten

Abstract Background Xeruborbactam (XERU) is a member of a new class of cyclic boronic acid β-lactamase inhibitors with inhibitory activity against major members of Class A, B, C, and D beta-lactamases. XERU is highly orally bioavailable when administered as the isobutyryloxymethyl prodrug, with a long terminal plasma half-life that supports once daily dosing. The purpose of these studies was to determine the pharmacodynamic parameter that best described the activity of XERU administered as the oral prodrug in combination with a fixed dosage regimen of ceftibuten in the neutropenic mouse thigh infection model. %24h Free Xeruborbactam Time &amp;gt; 4 mg/L 24h Free Xeruborbactam AUC Methods Three E. coli and five K. pneumoniae isolates were used in these studies. Ceftibuten MICs (with 4 mg/L XERU) ranged from 0.125 to 2 mg/L and included strains with ESBLs and KPC. Mice were rendered neutropenic, infected with ∼107 CFU/thigh and were treated with various doses of XERU in combination with ceftibuten (50 mg/kg q6h) by the PO route starting 2 hours post infection for 24 hours. The ceftibuten dosage regimen was designed to simulate once daily 800 mg oral doses in humans obtained from a previous Phase 1 study. Plasma exposures (PK) were measured in neutropenic, infected mice. The relationship between PK-PD indices and the reduction in the log number of CFU per thigh were analyzed by using the sigmoid maximum (Emax) PD model. Results The activity of xeru was best described by the % 24h free xeru plasma concentrations exceeded 4 mg/L and 24h free XERU plasma AUC. Xeru PK-PD Parameters in Combination with Ceftibuten Conclusion The PK-PD of XERU administered as the oral prodrug in combination with ceftibuten, and the clinical PK of both drugs support once-daily dosing for the treatment of cUTIs due to Enterobacterales, including ESBL- and carbapenemase-producing strains. Disclosures Ziad Tarazi, Qpex Biopharma: Employee Niki Roos, n/a, Qpex Biopharma: Employee Ted Page, n/a, Qpex Biopharma: Employee David Griffith, n/a, Qpex Biopharma: Employee.

592. Impact of Elevated MIC Values on Echinocandin Pharmacokinetic-Pharmacodynamic (PK-PD) Candida glabrata Target Attainment (TA)

592. Impact of Elevated MIC Values on Echinocandin Pharmacokinetic-Pharmacodynamic (PK-PD) <i>Candida glabrata</i> Target Attainment (TA)

217. A Phase 1 Study of the Safety, Tolerability, and Pharmacokinetics of Multiple Doses of the Lipopeptide QPX9003 in Healthy Adult Subjects

Abstract Background QPX9003 is a fully synthetic lipopeptide with potent activity against MDR Pseudomonas and Acinetobacter spp. This report describes the safety and pharmacokinetics of QPX9003 following single and multiple doses. Methods Twelve healthy subjects were enrolled in 2 cohorts of up to 8 subjects (each cohort randomized to have up to 6 active and 2 placebo) each in the multiple ascending dose phase (100 or 200 mg every 6 hrs). Subjects received a single dose of QPX9003 followed by 48 hours of washout, then were administered QPX9003 q6h for 7 days. All infusions were administered over 1 hour. Intensive plasma sampling was obtained after dosing and assayed for QPX9003 content using validated HPLC/MS methods. Results Single and multiple dose QPX9003 pharmacokinetic parameters (mean +/- SD) are shown below: No subjects discontinued due to AEs and no SAEs were observed. There was no evidence of increasing numbers or severity of AEs with increasing dose, and all AEs were mild or moderate in severity. Conclusion QPX9003 was safe and well tolerated at all doses tested. QPX9003 plasma AUC and Cmax increased with increasing dose. QPX9003 plasma exposure accumulated ∼ 1.5 fold over 7 days of q6h dosing consistent with its plasma half-life. Based on the PK and safety profile, QPX9003 produces plasma exposures that exceed the PK-PD target safely and warrants further clinical development. Disclosures David Griffith, n/a, Qpex Biopharma: Employee Yehuda Carmeli, MD, Allecra Therapeutics: Advisor/Consultant|MSD: Advisor/Consultant|Nabriva: Advisor/Consultant|Pfizer: Advisor/Consultant|Qpex Pharmaceuticals: Advisor/Consultant|Roche: Advisor/Consultant|Shinogi: Advisor/Consultant|Spero Therapeutics: Advisor/Consultant Shawnee Gehrke, n/a, Qpex Biopharma: Employee Elizabeth Morgan, n/a, Qpex Biopharma: Employee Michael Dudley, n/a, ArrePath: Board Member|Qpex Biopharma: Board Member|Qpex Biopharma: Employee Jeff Loutit, MBChB, Qpex Biopharma: Employee.