Single-dose Pharmacokinetic Studies Research Articles

Quercetin-Loaded Nanostructured Lipid Carrier In Situ Gel for Brain Targeting Through Intranasal Route: Formulation, In Vivo Pharmacokinetic and Pharmacodynamic Studies.

Quercetin (QT) shows potential for protecting against neurodegenerative diseases like Alzheimer's. However, its limited bioavailability and instability in physiological pH hinder its clinical use. The purpose of this work is to construct QT-filled nanostructured lipid carriers (QT-NLC) intranasal in situ gel to enhance pharmacokinetic and pharmacodynamic performance. NLCs were developed using a melt emulsification-high-pressure homogenization and were optimized using design expert software with the Box-Behnken design. NLCs were then incorporated into an in situ gel based on Lutrol F127 and further characterized. The pharmacodynamics of the formulation was evaluated in neurodegeneration induced by trimethyl tin (TMT) Wistar rats. The optimized QT in situ gel had spherical shape, entrapment efficiency of 96.1 ± 4.40%, and in vitro drug release of 83.74 ± 1.40%. The mean particle size was 123.3 ± 5.46nm. After intranasal administration, in vivo single-dose pharmacokinetic studies demonstrated a significant therapeutic concentration of drug in CNS, having Cmax 183.41 ± 11.76ng/mL and Tmax of 2h. The more brain targeting efficiency of NLCs was proved by the developed QT in situ gel, which had a higher drug targeting efficiency (DTE) of 117.47% and drug targeting potential (DTP) of 88.9%. As compared to the neurodegeneration control group, the QT in situ gel-treated group had significantly decreased escape latency and pathlength. Biochemical analysis and histological investigations demonstrated that QT in situ gel exhibited superior anti-Alzheimer's potential compared to standard drug, donepezil. The promising results of the developed and optimized intranasal QT in situ gel suggest its potential and can be used in Alzheimer's disease management.

Abstract 4043: KSHN001034: An intramuscular prodrug of fulvestrant to treat estrogen-receptor (ER) positive advanced metastatic breast cancer

Abstract Purpose: Breast cancer (BC) remains a considerable health concern, with over 75% of total cases accounting for ER+ BC. Fulvestrant, a selective estrogen receptor degrader (SERD), is the primary drug of choice for treating advanced metastatic ER+, BC. Currently, Faslodex® (500 mg) is given as an intramuscular (IM) depot that achieves the steady-state plasma concentration of 24-28 ng/mL of fulvestrant from day 28 onwards. Additionally, clinical studies suggest that current Faslodex® (500 mg) achieves insufficient blockade of ERα receptor plausibly due to suboptimal physicochemical and pharmacokinetic (PK) properties. Hence, achieving higher fulvestrant plasma concentrations is a significant unmet need to improve efficacy and inhibit the development of drug resistance. To overcome these issues, we modified the physicochemical properties of the fulvestrant to enhance its solubility by developing a prodrug, KSHN001034, with the potential to deliver higher fulvestrant plasma exposures. Methods: KSHN001034 was evaluated for its physicochemical and ADME properties. Thermodynamic solubility and liver microsomal stability were performed. KSHN001034 was formulated as 100 mg/mL compared with Faslodex (50 mg/mL). Single-dose PK studies were performed using KSHN001034 in Sprague Dawley (SD) rats and Beagle Dogs post-IM administration for 7 and 14 days, respectively. The uterotrophic activity was investigated by determining changes in uterine weight in juvenile female SD rats for KSHN001034 (10 mg/kg, IP) and fulvestrant (25 mg/kg, SC). The ERα expression was also evaluated in rat uterus tissue via a simple western assay. Results: A remarkable improvement (~1100 fold) was achieved for KSHN001034 in aqueous solubility (1.112 mg/mL) vs. fulvestrant (<1 µg/mL). Significant improvement was observed in metabolic stability vs. fulvestrant. KSHN001034 showed significant improvement in PK exposure of fulvestrant upon IM administration in rats and dogs with higher AUC and Cmax compared to that of Faslodex. Relative bioavailability of fulvestrant post-KSHN001034 treatment was found to be >6-fold in rats and ~2.5 fold in dogs compared to Faslodex. Treatment of KSHN001034 antagonized estradiol (E2)-mediated uterine stimulation, exhibiting significant inhibition (85%) of uterotrophic activity vs. fulvestrant (73%). KSHN001034 reduced E2-induced uterus weight, supporting efficacy due to released fulvestrant as it is a true SERD. Additionally, KSHN001034 significantly inhibited the E2-induced ERα expression in rat uterus. Conclusions: Overall, KSHN001034 indicates the potential to deliver higher fulvestrant concentrations that would effectively block the ERα receptor resulting in improved efficacy and minimal emergence of resistance. Further, enhanced solubility and reduced injection volume would result in better patient compliance. Citation Format: Heta Pandya, Ganesh Sangle, Vishal Unadkat, Vishal Goswami, Parva Purohit, Chirag Mehta, Sonam Sinha, Ketan Variya. KSHN001034: An intramuscular prodrug of fulvestrant to treat estrogen-receptor (ER) positive advanced metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4043.

Enhanced oral bioavailability and antitumor therapeutic efficacy of sorafenib administered in core-shell protein nanoparticle.

Orally delivered molecularly targeted small-molecule drugs play a significant role in managing cancer as a chronic disease. However, due to the poor oral bioavailability of some of these molecules, high-dose administration is required leading to dose-limiting toxicity especially when delivered daily for a long duration. Here, we report an oral nanoformulation for small-molecule multi-kinase inhibitor, sorafenib tosylate, showing nearly twofold enhancement in the oral bioavailability and enhanced therapeutic efficacy with a better safety profile compared to the current clinical formulation. Using a scalable process involving high-pressure homogenization, sorafenib was loaded into an albumin nanocarrier at ~ 50 w/w%. Repeated preparation of gram-scale batches (n = 7) showed an average particle size of 180 ± 9nm, encapsulation efficiency of 95 [Formula: see text] 2%, and drug-loading efficiency of 48 [Formula: see text] 0.7%. Further, surface engineering with a mucoadhesive layer on nanoparticles (referred to as ABSORF) resulted in the final size of 299 ± 38nm and surface charge of -54 ± 8mV. Single-dose and multidose pharmacokinetic studies showed twofold enhancement in the plasma concentration of sorafenib compared to current clinically used tablets. Antitumor efficacy studies in the orthotopic rat liver tumor model showed significant tumor regression (p value = 0.0037) even at half dose (eqv. to 200mg of human equivalent dose) of ABSORF compared to clinical control (eqv. to 400mg). The biodistribution of sorafenib from ABSORF was higher in the liver; however, liver and kidney function test parameters were comparable with that of the 2 × dose of clinical control. No abnormalities and signs of toxicity were seen in the histopathological analysis for ABSORF-treated animals. In summary, we demonstrate a scalable preparation of small-molecule drug-loaded nanoformulation with approximately twofold enhancement in oral bioavailability, improved antitumor efficacy, and acceptable toxicity profile.

Repurposing Ferumoxytol as a Breast Cancer-Associated Macrophage Tracer with Five-Dimensional Quantitative [Fe]MRI of SPION Dynamics.

Simple SummaryWith the incorporation of immune-modulating therapies into the standard management of triple-negative breast cancer, there is increased interest in the non-invasive imaging of the tumor immune microenvironment. Ferumoxytol is FDA-approved as an iron replacement therapy for iron-deficiency anemia and is also a superparamagnetic iron oxide nanoparticle (SPION) resulting in negative enhancement on T2-weighted MR imaging. It has previously been established that ferumoxytol is taken up by macrophages. In the current study, we used ferumoxytol-contrasted MRI to quantitatively image the iron concentration, and, by extension, the tumor-associated macrophage infiltration within the tumor microenvironment of a highly inflammatory model of triple-negative breast cancer.Tumor-associated macrophages (TAMs) in breast cancer regulate inflammation, immunosuppression, angiogenesis, and metastasis. However, TAM imaging remains a clinical challenge. Ferumoxytol has long been an FDA-approved superparamagnetic iron oxide nanoparticle (SPION) preparation used as an intravenous (IV) treatment for iron-deficiency anemia. Given its high transverse relaxivity, ferumoxytol produces a negative image contrast upon cellular uptake in T2-weighted magnetic resonance imaging (MRI) studies. Here we evaluated ferumoxytol as a contrast agent to image/quantify TAMs in an aggressive mouse model of breast cancer: We developed [Fe]MRI to measure the 5-dimensional function c(x,y,z,t), where c is the concentration of nanoparticle iron and {x,y,z,t} is the 4-dimensional set of tumor space-time coordinates. Ferumoxytol SPIONs are readily phagocytosed (~104/cell) by the F4/80+CD11b+ TAMs within breast tumors. Quantitative [Fe]MRIs served to determine both the spatial and the temporal distribution of the SPION iron, and hence to measure [Fe] = c(x,y,z,t), a surrogate for TAM density. In single-dose pharmacokinetic studies, after an IV dose of 5 mg/Kg iron, [Fe]MRI measurements showed that c(x,y,z,t) within breast tumors peaked around [Fe] = 70 μM at 42 h post-administration, and decayed below the [Fe]MRI detection limit (~2 μM) by day 7. There was no SPION uptake in control organs (muscle and adipose tissue). Optical microscopy of tissue sections confirmed that F4/80+CD11b+ TAMs infiltrated the tumors and accumulated SPION iron. Our methodology and findings have translational applications for breast cancer patients.

Fulvestrant-3-Boronic Acid (ZB716) Demonstrates Oral Bioavailability and Favorable Pharmacokinetic Profile in Preclinical ADME Studies.

Fulvestrant-3-boronic acid (ZB716), an oral selective estrogen receptor degrader (SERD) under clinical development, has been investigated in ADME studies to characterize its absorption, metabolism, and pharmacokinetics. ZB716 was found to have high plasma protein binding in human and animal plasma, and low intestinal mucosal permeability. ZB716 had high clearance in hepatocytes of all species tested. ZB716 was metabolized primarily by CYP2D6 and CYP3A. In human liver microsomes, ZB716 demonstrated relatively low inhibition of CYP1A2, 2C8, 2C9, 2C19, 2D6, and 3A4 (when testosterone was used as the substrate), and no inhibition of CYP2B6 and 3A4 (when midazolam was used as the substrate). In assays for enzyme activity, ZB716 induced CYP1A2, 2B6, and 3A4 in a concentration-dependent manner. Single-dose and repeated-dose pharmacokinetic studies in rats and dogs showed oral bioavailability, dose-proportional drug exposure, and drug accumulation as measured by maximum concentration and area under the concentration–time curve (AUC).

Bio-Distribution and Pharmacokinetics of Topically Administered γ-Cyclodextrin Based Eye Drops in Rabbits.

The purpose of this study was to evaluate the ocular pharmacokinetics, bio-distribution and local tolerability of γ-cyclodextrin (γCD) based irbesartan 1.5% eye drops and candesartan 0.15% eye drops after single and multiple topical administration in rabbit eyes. In this randomized, controlled study, a total number of 59 New Zealand White albino rabbits were consecutively assigned to two study groups. Group 1 (n = 31) received irbesartan 1.5% and group 2 (n = 28) candesartan 0.15% eye drops. In both groups, single dose and multiple administration pharmacokinetic studies were performed. Rabbits were euthanized at five predefined time points after single-dose administration, whereas multiple-dose animals were dosed for 5 days twice-daily and then euthanized 1 h after the last dose administration. Drug concentration was measured by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the retinal tissue, vitreous humor, aqueous humor, corneal tissue and in venous blood samples. Pharmacokinetic parameters including maximal drug concentration (Cmax), time of maximal drug concentration (Tmax), half-life and AUC were calculated. To assess local tolerability, six additional rabbits received 1.5% irbesartan eye drops twice daily in one eye for 28 days. Tolerability was assessed using a modified Draize test and corneal sensibility by Cochet Bonnet esthesiometry. Both γCD based eye drops were rapidly absorbed and distributed in the anterior and posterior ocular tissues. Within 0.5 h after single administration, the Cmax of irbesartan and candesartan in retinal tissue was 251 ± 142 ng/g and 63 ± 39 ng/g, respectively. In the vitreous humor, a Cmax of 14 ± 16 ng/g for irbesartan was reached 0.5 h after instillation while Cmax was below 2 ng/g for candesartan. For multiple dosing, the observed Cmean in retinal tissue was 338 ± 124 ng/g for irbesartan and 36 ± 10 ng/g for candesartan, whereas mean vitreous humor concentrations were 13 ± 5 ng/g and <2 ng/g, respectively. The highest plasma concentrations of both irbesartan (Cmax 5.64 ± 4.08 ng/mL) and candesartan (Cmax 4.32 ± 1.04 ng/mL) were reached 0.5 h (Tmax) after single administration. Local tolerability was favorable with no remarkable differences between the treated and the control eyes. These results indicate that irbesartan and candesartan in γCD based nanoparticle eye drops can be delivered to the retinal tissue of the rabbit’s eye in pharmacologically relevant concentrations. Moreover, safety and tolerability profiles appear to be favorable in the rabbit animal model.

Antimicrobial dosing in prolonged intermittent renal replacement therapy: a systematic review

AbstractAimThe research aim was to conduct a systematic review of the literature regarding the pharmacokinetics (PK) and dosing of antimicrobials in prolonged intermittent renal replacement therapy (PIRRT), a hybrid form of dialysis becoming increasingly utilised in critical care.MethodsA literature review was performed using PubMed from database inception to October 2020 according to the PRISMA guidelines. All papers published in English language were included in the review. Two researchers independently conducted literature searches, screened abstracts and full text and came to agreement as to which articles were suitable for inclusion before compiling the relevant data into a spreadsheet. The types of papers retrieved varied between case reports, single and multiple dose pharmacokinetic studies and Monte Carlo simulations.ResultsA total of 149 articles were found in the initial literature review and via other sources. Of these papers, 50 articles were deemed eligible for inclusion. These studies included one to 34 patients. PIRRT settings varied between institutions, including filter surface area, duration of PIRRT and type of dialyser used. With the exception of vancomycin and meropenem, few antimicrobials had sufficient data available from which reasonable empiric dosing regimens can be recommended.ConclusionThere is limited data to guide dosing of antimicrobials during PIRRT. More studies are required to understand how dosing can be optimised in this population of critically ill patients.

Selecting an anti-malarial clinical candidate from two potent dihydroisoquinolones

BackgroundThe ongoing global malaria eradication campaign requires development of potent, safe, and cost-effective drugs lacking cross-resistance with existing chemotherapies. One critical step in drug development is selecting a suitable clinical candidate from late leads. The process used to select the clinical candidate SJ733 from two potent dihydroisoquinolone (DHIQ) late leads, SJ733 and SJ311, based on their physicochemical, pharmacokinetic (PK), and toxicity profiles is described.MethodsThe compounds were tested to define their physicochemical properties including kinetic and thermodynamic solubility, partition coefficient, permeability, ionization constant, and binding to plasma proteins. Metabolic stability was assessed in both microsomes and hepatocytes derived from mice, rats, dogs, and humans. Cytochrome P450 inhibition was assessed using recombinant human cytochrome enzymes. The pharmacokinetic profiles of single intravenous or oral doses were investigated in mice, rats, and dogs.ResultsAlthough both compounds displayed similar physicochemical properties, SJ733 was more permeable but metabolically less stable than SJ311 in vitro. Single dose PK studies of SJ733 in mice, rats, and dogs demonstrated appreciable oral bioavailability (60–100%), whereas SJ311 had lower oral bioavailability (mice 23%, rats 40%) and higher renal clearance (10–30 fold higher than SJ733 in rats and dogs), suggesting less favorable exposure in humans. SJ311 also displayed a narrower range of dose-proportional exposure, with plasma exposure flattening at doses above 200 mg/kg.ConclusionSJ733 was chosen as the candidate based on a more favorable dose proportionality of exposure and stronger expectation of the ability to justify a strong therapeutic index to regulators.

Streptomycin sulphate loaded solid lipid nanoparticles show enhanced uptake in macrophage, lower MIC in Mycobacterium and improved oral bioavailability

Present study addresses the challenge of incorporating hydrophilic streptomycin sulphate (STRS; log P −6.4) with high dose (1 g/day) into a lipid matrix of SLNs. Cold high-pressure homogenization technique used for SLN preparation achieved 30% drug loading and 51.17 ± 0.95% entrapment efficiency. Polyethylene glycol 600 as a supporting-surfactant assigned small size (218.1 ± 15.46 nm) and mucus-penetrating property. It was conceived to administer STRS-SLNs orally rather than intramuscularly. STRS-SLNs remained stable on incubation for varying times in SGF or SIF.STRS-SLNs were extensively characterised for microscopic (TEM and AFM), thermal (DSC), diffraction (XRD) and spectroscopic (NMR and FTIR) properties and showed zero-order controlled release.Enhanced (60 times) intracellular uptake was observed in THP-1 and Pgp expressing LoVo and DLD-1 cell lines, using fluorescein-SLNs. Presence of SLNs in LoVo cells was also revealed by TEM studies. STRS-SLNs showed 3 times reduction in MIC against Mycobacterium tuberculosis H37RV (256182) in comparison to free STRS. It also showed better activity against both M. bovis BCG and Mycobacterium tuberculosis H37RV (272994) in comparison to free STRS. Cytotoxicity and acute toxicity studies (OECD 425 guidelines) confirmed in vitro and in vivo safety of STRS-SLNs. Single-dose oral pharmacokinetic studies in rat plasma using validated LCMS/MS technique or the microbioassay showed significant oral absorption and bioavailability (160% − 710% increase than free drug).

0745 The Pharmacokinetics of FT218, Once Nightly Sodium Oxybate: Food Effect and Bioavailability Compared to Twice Nightly Sodium Oxybate

Abstract Introduction Sodium oxybate is an effective treatment for excessive daytime sleepiness and cataplexy in patients with narcolepsy. The FDA approved formulation requires twice-nightly dosing; at bedtime and 2.5 - 4 hours later. FT218 is a controlled-release formulation of sodium oxybate intended for once-nightly dosing, using Avadel’s proprietary Micropump™ technology. The objective of this study was to evaluate the relative bioavailability of investigational once-nightly sodium oxybate, FT218, 6 g, compared to commercially available twice-nightly sodium oxybate and the food effect of FT218. Methods Two crossover, single-dose pharmacokinetic studies were conducted in healthy volunteers. The first, a relative bioavailability study (n=28) was completed comparing FT218 6 g to twice-nightly sodium oxybate 6 g (in two divided doses of 3 g). The second, evaluated the food effect (n=16) of FT218 6g in the Fed vs. Fasted state. Results FT218 had a lower overall Cmax than twice-nightly sodium oxybate, while AUC was equivalent. C8h level and variability was comparable between FT218 and twice-nightly sodium oxybate. In the Fed, compared to the Fasted state, FT218 had a longer Tmax, lower Cmax and decreased AUC (Cmax 67%, AUC 86%, Tmax 1-hour slower than Fasted values). Adverse Events with FT218 were mostly mild or moderate in severity, non-serious and known AEs associated with sodium oxybate. The safety profiles of FT218 and twice-nightly sodium oxybate at 6 g appeared similar. Conclusion Once-nightly FT218 at 6 g demonstrated a lower overall Cmax and similar exposure to twice-nightly sodium oxybate, with similar C8h plasma levels and C8h variability. In the Fed state, AUC and Cmax of FT218 was lower than in the Fasted State. FT218 was generally safe and well tolerated and the safety profile appeared comparable to twice-nightly sodium oxybate. Support This work was supported by Avadel Pharmaceuticals.

A mechanistic pharmacokinetic model with drug and antidrug antibody interplay, and its application for assessing the impact of immunogenicity response on bioequivalence testing.

AimsSingle‐dose pharmacokinetic (PK) studies in healthy subjects have been the design of choice for bioequivalence determination for decades. This preference has been recently extended to PK similarity studies of proposed biosimilars. However, PK similarity studies can be complicated by the effect of immunogenicity response on drug disposition. The impact is exacerbated when there is an imbalance in host‐specific immunological characteristics of subjects between the test and reference groups. Such complications remain poorly understood. The purpose of this communication is to show that the impact of immunogenicity response on PK similarity determination can be critical, using adalimumab as an example.MethodsData for adalimumab concentrations and immunogenicity response over 10 weeks were obtained from 133 healthy subjects receiving a 40 mg dose of Humira® in a PK similarity study. Also, a population PK model with a mechanistic construct for delineating the interplay between adalimumab disposition and antidrug antibodies response was utilized to estimate via simulation the probability that a PK similarity study would fail in typical study settings.ResultsThe simulations showed that the immunogenicity response can have a profound impact on the outcome of PK similarity determination. As such, the probability of failing to achieve the similarity conclusion increased to 51.9%, from 13.8% in the absence of immunogenicity response.ConclusionThis study provides a model‐based framework for better understanding of how a PK similarity study can be optimally designed and for interpretation of the outcome of PK similarity determination when the drug disposition is affected in the presence of immunogenicity response.

Pharmacokinetics and efficacy of orally administered polymeric chloroquine as macromolecular drug in the treatment of inflammatory bowel disease

Inflammatory bowel disease is a chronic inflammation of the gastrointestinal tract with poor understanding of its pathogenesis and no effective cure. The goal of this study was to evaluate the feasibility of orally administered non-degradable polymeric chloroquine (pCQ) to locally reduce colon inflammation. The pCQ was synthesized by radical copolymerization of N-(2-hydroxypropyl)methacrylamide with methacryloylated hydroxychloroquine (HCQ). The anti-inflammatory activity of orally administered pCQ versus HCQ was tested in a mouse model of colitis induced by Citrobacter rodentium (C. rodentium). Single-dose pharmacokinetic and biodistribution studies performed in the colitis model indicated negligible systemic absorption (p ≤ 0.001) and localization of pCQ in the gastrointestinal tract. A multi-dose therapeutic study demonstrated that the localized pCQ treatment resulted in significant reduction in the colon inflammation (p ≤ 0.05). Enhanced suppression of pro-inflammatory cytokines IL-6 (p ≤ 0.01) and IL1-β and opposing upregulation of IL-2 (p ≤ 0.05) recently reported to be involved in downstream anti-inflammatory events suggested that the anti-inflammatory effects of the pCQ are mediated by altering mucosal immune homeostasis. Overall, the reported findings demonstrate a potential of pCQ as a novel polymer therapeutic option in inflammatory bowel disease with the potential of local effects and minimized systemic toxicity.

Rational design and development of a stable liquid formulation of riluzole and its pharmacokinetic evaluation after oral and IV administrations in rats

Enterally administered riluzole is currently being investigated in a Phase II/III clinical trial for the treatment of acute spinal cord injury (SCI). Many SCI patients suffer from severe motor dysfunction and exhibit swallowing difficulties and cannot swallow riluzole tablets. The purpose of the present study was to develop a liquid solution formulation of riluzole, which can be administered more easily to this patient population with the capability to adjust the dose if needed. Riluzole was solubilized using water miscible organic solvents, namely, polyethylene glycol 400, propylene glycol and glycerin. A Central Composite Design (CCD) approach was used to develop an optimum co-solvent composition that can solubilize the entire 50 mg dose of riluzole in 5 ml. A three-factor five-level design was employed to investigate the effects of composition of co-solvents on riluzole solubility. The selected optimum formulation consists of 15% v/v PEG 400, 20% v/v propylene glycol and 10% v/v glycerin, with riluzole concentration of 10 mg/ml. The optimum composition was assessed for stability at different temperatures. Satisfactory stability was obtained at room temperature and 4 °C (t90 of 17 and 35 months, respectively). The optimum formulation of riluzole was suitable for both oral and intravenous administrations. Single dose pharmacokinetic studies of the optimum formulation by oral and IV routes were evaluated in rats, using commercially available Rilutek® tablets as a reference. The co-solvent formulation was well tolerated both orally and intravenously. In comparison to the commercial tablet, the co-solvent formulation had a faster rate of absorption and more sustained plasma levels with a significantly longer elimination half-life. Higher concentrations of riluzole in brain and spinal cord were achieved from co-solvent formulation as compared to tablet. The riluzole solution formulation is stable and offers advantages of ease of administration, consistent dosing, rapid onset and longer duration of action, better availability at site of action which can be extremely beneficial for the therapy in SCI patients.

Abstract LB-018: ARQ 531, a novel and reversible inhibitor of Bruton's tyrosine kinase, displays favorable oral bioavailability and exposure in patients with B-cell malignancies

Abstract Background: ARQ 531 is a novel, ATP competitive reversible inhibitor Bruton's tyrosine kinase (BTK). BTK is a key regulator of the B cell receptor (BCR) signaling pathway that mediates signaling from the cell surface to the cytoplasm and into the nucleus. ARQ 531 is not metabolized by any of the major drug metabolizing CYP450 enzymes. Here we report pharmacokinetic profile of ARQ 531 in a phase I study evaluating safety, pharmacokinetics and pharmacodynamics activity and clinical activity of ARQ 531 in selected subjects with relapsed/refractory B-cell malignancies. Preclinical studies in rats, dogs and monkeys are also described. Methods: Oral and intravenous single dose pharmacokinetic studies of ARQ 531 were conducted in rats, dogs, and monkeys to determine oral bioavailability and drug exposure. In a standard ‘3+3' dose-escalation study design, ARQ 531 was given orally once per day beginning at 5 mg/dose and escalating for 4 weeks [NCT03162536]. Plasma samples were collected to determine ARQ 531 concentrations and whole blood / PBMCx to quantify pBTK inhibition. Plasma samples from each species were analyzed by liquid chromatography-mass spectrometry/ mass spectrometry (LC-MS/MS). Results: Consistent with preclinical studies, patients enrolled in the phase I study showed favorable exposures, the steady state peak to trough ratio was generally 3:1 or lower. ARQ 531 had an elimination half-life at steady state of ~24 hr and Cmax occurred 2 to 3 hours after dosing. Pharmacodynamic changes included suppression of BTK phosphorylation. No drug related AEs or DLTs have been observed thus far in the study. Conclusions: ARQ 531 demonstrates a favorable PK profile in humans supporting once daily dosing. Sufficient plasma levels are attained and high levels of pBTK inhibition in peripheral blood can be achieved following oral dosing. Additional dose and schedule evaluations continue, and updated clinical and biomarker results will be presented. Citation Format: Terence Hall, Yi Yu, Sudharshan Eathiraj, Deborah Stephens, Ian Flinn, Jennifer Woyach, Brian Schwartz, Ronald E. Savage. ARQ 531, a novel and reversible inhibitor of Bruton's tyrosine kinase, displays favorable oral bioavailability and exposure in patients with B-cell malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-018.

Integrating data from the Investigational Medicinal Product Dossier/investigator's brochure. A new tool for translational integration of preclinical effects.

Integrating data from the Investigational Medicinal Product Dossier/investigator's brochure. A new tool for translational integration of preclinical effects.

In Vivo Pharmacokinetics and Pharmacodynamics of APX001 against Candida spp. in a Neutropenic Disseminated Candidiasis Mouse Model.

APX001 is the prodrug of APX001A, which is a first-in-class small molecule with a unique mechanism of action that inhibits the fungal enzyme Gwt1 in the glycosylphosphatidylinositol (GPI) biosynthesis pathway. The goal of the present study was to determine which pharmacokinetic/pharmacodynamic (PK/PD) index and magnitude best correlated with efficacy in the murine disseminated candidiasis model for Candida albicans (n = 5), C. glabrata (n = 5), and C. auris (n = 4). MIC values ranged from 0.002 to 0.03 mg/liter for C. albicans, from 0.008 to 0.06 mg/liter for C. glabrata, and from 0.004 to 0.03 mg/liter for C. auris Plasma APX001A pharmacokinetic measurements were performed in mice after oral administration of 4, 16, 64, and 256 mg/kg of body weight APX001. Single-dose pharmacokinetic studies exhibited maximum plasma concentration (Cmax) values of 0.46 to 15.6 mg/liter, area under the concentration-time curve (AUC) from time zero to infinity (AUC0-inf) values of 0.87 to 70.0 mg · h/liter, and half-lives of 1.40 to 2.75 h. A neutropenic murine disseminated candidiasis model was utilized for all treatment studies, and drug dosing was by the oral route. Dose fractionation was performed against C. albicans K1, with total doses ranging from 4 to 1,024 mg/kg/day of APX001 fractionated into regimens of dosing every 3, 6, 8, and 12 h for a 24-h treatment duration. Nonlinear regression analysis was used to determine which PK/PD index best correlated with efficacy on the basis of the reduction in the number of CFU/kidney at 24 h. The 24-h free-drug AUC/MIC ratio (fAUC0-24/MIC) was the PK/PD index that best correlated with efficacy (coefficient of determination [R2] = 0.88). Treatment studies with the remaining strains utilized regimens of 1 to 256 mg/kg of APX001 administered every 6 h for a 24-h duration with C. albicans and a 96-h study duration with C. glabrata and C. auris The dose required to achieve 50% of the maximum effect (ED50) and stasis fAUC/MIC targets were as follows: for C. albicans, 3.67 ± 3.19 and 20.60 ± 6.50, respectively; for C. glabrata, 0.38 ± 0.21 and 1.31 ± 0.27, respectively; and for C. auris, 7.14 ± 4.54 and 14.67 ± 8.30, respectively. The present studies demonstrated in vitro and in vivo APX001A and APX001 potency, respectively, against C. albicans, C. glabrata, and C. auris. These results have potential relevance for clinical dose selection and evaluation of susceptibility breakpoints. The identification of a lower AUC/MIC ratio target for C. glabrata suggests that species-specific susceptibility breakpoints should be explored.

Therapeutic administration of inhaled INS1009, a treprostinil prodrug formulation, inhibits bleomycin-induced pulmonary fibrosis in rats

Idiopathic pulmonary fibrosis is a progressive and lethal disease and while there are now two approved drugs (Esbriet® and Ofev®) additional effective treatments are still needed. Recently, prostacyclin analogs such as iloprost and treprostinil (TRE) have been shown to exert some protection against bleomycin-induced pulmonary fibrosis in mice when administered in a prophylactic regimen. In this study, we evaluated the effect of the inhaled treprostinil prodrug hexadecyl-treprostinil (C16TR) formulated in a lipid nanoparticle (INS1009) administered therapeutically in a fibrotic rat model. Male Fischer 344 rats challenged with intra-tracheal saline instillation were then treated with daily inhaled phosphate buffered saline (PBS) while rats challenged with bleomycin sulfate (3.5–4.0 mg/kg) instillation were treated with either daily inhaled PBS, daily inhaled INS1009 (10, 30, or 100 μg/kg), or twice-daily orally with the anti-fibrotic compound pirfenidone (100 mg/kg). Dosing started on day 10 post-bleomycin challenge and continued until day 27 after bleomycin. Lungs were harvested 24 h after the last dose of treatment for evaluation of lung hydroxyproline content and pulmonary histology. Lung hydroxyproline content increased from 421 μg/lung lobe in saline challenged and PBS treated animals to 673 μg/lung lobe in bleomycin challenged and PBS treated rats. Treatment of bleomycin challenged rats with 10, 30, or 100 μg/kg INS1009 dose-dependently reduced lung hydroxyproline content to 563, 501, and 451 μg/lung lobe, respectively, and pirfenidone decreased hydroxyproline content to 522 μg/lung lobe. Histologically, both INS1009 (100 μg/kg) and pirfenidone (100 mg/kg) reduced the severity of subepithelial fibrosis. Single dose pharmacokinetic (PK) studies of inhaled INS1009 in bleomycin challenged rats showed dose-dependent increases in lung C16TR concentration and plasma TRE on day 10 post-bleomycin challenge. Multiple dose PK studies of inhaled INS1009 showed dose-dependent increases only in lung C16TR concentration on day 27 post-bleomycin challenge. We also investigated the effects of TRE on the cytokine transforming growth factor-β1 (TGF-β1)-stimulated collagen gene and protein expressions in cultured human lung fibroblasts, assessed by real-time PCR and Sirius Red staining, respectively. In human fibroblasts, TRE (0.001–10 μM) inhibited TGF-β1 (20 ng/mL)-induced expression of collagen mRNA and protein in a concentration-dependent manner. These results demonstrated that inhaled INS1009, administered in a therapeutic dosing paradigm, dose-dependently (10–100 μg/kg) inhibited bleomycin-induced pulmonary fibrosis in rats. This effect may involve direct actions of TRE in suppressing collagen expression in lung fibroblasts.

A VALIDATED LC-MS/MS METHOD FOR PHARMACOKINETIC STUDY OF BRIVARACETAM IN HEALTHY RABBITS

Objective: A liquid chromatography-tandem mass spectrophotometric (LC–MS/MS) method was developed for quantification of brivaracetam in rabit plasma employing liquid-liquid extraction with ethyl acetate.Methods: Developed method was validated for specificity, precision, accuracy, recovery, and stability characteristics. Chromatographic separation was achieved on Chromolith C18column (100 mmx4.6 mmx5 µm) with 0.1% formic acid, adjusted to pH 3.2 as an isocratic mobile phase with a flow rate of 1.0 ml/min. the developed method was applied to assess pharmacokinetics parameters like Cmax, Tmax, t1/2 and AUC of brivaracetam in healthy rabbits.Results: The developed method was linear over the range of 0.16 to 8µg/ml. The regression equation for the analysis was Y=0.0053x+0.0018 with coefficient of correction (r2) = 0.998. The % mean recovery for brivaracetam was found to be between 95.7% to 106.5%. The mean intraday and inter-day precision of the method was found to be 0.77 to 3.72% for quality control standards. Brivaracetam showed Tmax of 1.025±0.061 and mean Cmax, AUC0®t andAUC0®a for Test formulation is 92.7±4.4, 496.21±26.4 and 504.20±30.68 respectively.Conclusion: A highly specific, rugged and rapid method with sufficiently low LLOQ was developed for analysis of routine samples of a single dose or multiple dose pharmacokinetic studies with any marketing formulation of brivaracetam.

Development of a Rapid and Precise Reversed-phase High-performance Liquid Chromatography Method for Analysis of Docetaxel in Rat Plasma: Application in Single-dose Pharmacokinetic Studies of Folate-targeted Micelles Containing Docetaxel.

Background:A simple and sensitive reversed-phase high-performance liquid chromatography (HPLC) method based on liquid-liquid extraction was established and validated for determination of docetaxel (DTX) in plasma of rat.Materials and Methods:Samples were spiked with paclitaxel as the internal standard and the chromatographic separation was carried out using C18 HPLC column. The mobile phase consisted of a mixture of acetonitrile/water with the ratio of 60/40 v/v. The ultraviolet detector was operated at 230 nm, and the flow rate of mobile phase was 1 ml/min. The method was validated for linearity, precision, accuracy, recovery, and limit of quantification (LOQ). Then the method was applied to quantify DTX in the rat plasma after intravenous (IV) administration of the self-assembled micelles of folate-targeted Synpronic F127/cholesterol (FA-PF127-Chol) loaded with DTX and Taxotere® as the reference marketed solution of DTX. The blood samples were taken from the ophthalmic vein at predetermined time intervals after treatment.Results:Calibration curve was linear between the concentration ranges of 0.1–7.5 μg/ml with the relative standard deviation % and evaluating error % ranged from 2.263 to 15.53 and −12.75 to 12.7 for intra- and inter-day validity, respectively. The mean recovery of the drug after plasma extraction was 95.67 ± 0.99% for the concentration of 1 μg/ml. The LOQ and the limit of detection for DTX in serum were 100 ng/ml and 30 ng/ml, respectively.Conclusions:The results indicated that the developed method could be adopted for pharmacokinetic studies of DTX-loaded FA-PF127-Chol micelles and Taxotere® in rat.

Efficacy and toxicity of HLX07 as a new anti-EGFR monoclonal antibody for epithelial cancers.

e14078 Background: EGFR is a validated target for anti-cancer drug development. Several anti-EGFR monoclonal antibodies (mAb) are used in clinics, but associated with a variety of toxicities. A new anti-EGFR mAb might offer better efficacy with less toxicities. Methods: we have developed a new humanized anti-EGFR mAb, HLX07, through engineering of Fab portion and improvement of glycosylation profile and tested in in vitro assays, in vivo xenograft animal models and primate pharmacokinetic (PK) and toxicokinetic (TK) studies. Results: HLX07 exerted potent antibody-dependent, cell-mediated cytotoxicity in vitro. It specifically binds to monkey and human but not rodent EGFR. HLX07 has better binding affinity to human EGFR, compared with cetuximab (KD 1.43x10-10 vs. 2.62x10-10). HLX07 completely inhibited the phosphorylation of EGFR in H292 cells at ≥0.1 nM, The IC50 of HLX07 for DiFi and H292 cells were 54.2 and 23.9 ng/mL, respectively, compared with 63.7 and 37.2 ng/mL by cetuximab, respectively. In vivo xenogenic studies also demonstrated that HLX07 significantly inhibited the growth of H292, A432 and WiDi cells in a dose-dependent manner. Xenogenic studies also showed that HLX07 used with gemcitabine and/or cisplatin was more active than either agent alone. HLX07 was more effective than cetuximab in inhibiting the growth of FaDu cells when used with local radiotherapy in vivo. Single-dose and 13-week repeat-dose GLP pharmacokinetic and toxicokinetic studies in cynomulgus monkeys up to 60 mg/kg/wk shows minimal-to-mild toxicities (see table). Conclusions: The detailed preclinical characterization indicates that HLX07 has better efficacy and less toxicity than cetuximab. A phase 1 first-in-human study is ongoing (NCT02648490). [Table: see text]