Inflammation and Intracellular Exposure of Dolutegravir, Darunavir, Tenofovir and Emtricitabine in People living with HIV

Background: Antiretroviral therapy reduces systemic inflammation and immune activation, but not to levels like HIV-negative. Limited drug penetration within tissues has been argued as potential mechanism of persistent inflammation. Data on the role of inflammation on plasma/intracellular (IC) pharmacokinetics (PK) of ARV drugs through to downregulation/expression of cytochrome P450 3A/membrane transport proteins are limited. Aim of this study was to investigate the correlation between inflammation markers and plasma/IC PK of different ARVs regimen in HIV-positive patients. Methods: We included in the study ART-treated HIV+ pts switching to 3 different ARV regimens: 1) DTG-based dual-therapy plus boosted-PIs, 2) DTG-based triple-therapy without PIs, 3) DRV/c-based triple-therapy. Plasma and IC ARV drugs concentration means at the end of dosing interval (T0), IM on samples concomitantly with ARV PK determination: sCD14, CRP, IL-6 and LPS were analysed. Results: 60 samples from pts included in the switching study were used for measuring plasma and IC concentrations of HIV drugs. No significative differences between CRP, sCD14, IL-6 and LPS values in 3 arms of therapy were observed. Significant correlation was observed between tenofovir plasma concentrations and sCD14 (p<0.001), DRV plasma concentration and sCD14 (p=0,07) and DRV IC/plasma ratio and Log10 IL-6 concentrations (p=0.04). Furthermore, in 24 pts on DTG-TT, we observed a negative trend between DTG IC concentrations and sCD14 (p=0.09). Conclusions: Our preliminary data support the hypothesis of lower IC concentrations of DRV and DTG in pts with higher plasma IM, suggesting an interplay between HIV drug penetration and persistent inflammation in cART-treated HIV-positive patients.

pH-responsive size-shrinkable mesoporous silica-based nanocarrier for improved tumor penetration and therapeutic efficacy

Poor tumor penetration is a major obstacle to nanomedicine for achieving effective anticancer therapy. Tumor microenvironment-induced nanomedicine size shrinkage is a promising strategy to overcome the drug penetration barrier across...

Translational Development of A Tumor Junction Opening Technology

Our goal is to overcome treatment resistance in ovarian cancer patients, which occurs in most cases after an initial positive response to chemotherapy. A central resistance mechanism is the maintenance of desmoglein-2 (DSG2)-positive tight junctions between malignant cells, which prevents drug penetration into the tumor. We generated JO4, a recombinant protein that binds to DSG2, resulting in the transient opening of junctions in epithelial tumors. Here, we present studies on the clinical translation of JO4 in combination with PEGylated liposomal doxorubicin/Doxil® for ovarian cancer therapy. A manufacturing process for cGMP-compliant production of JO4 was developed. GLP toxicology studies using material from this process in DSG2 transgenic mice and cynomolgus macaques showed no treatment-related toxicities after intravenous injection at doses reaching 24 mg/kg. Multiple cycles of intravenous JO4 plus Doxil® (4 cycles, 4 weeks apart, simulating the treatment regimen in the clinical trial) elicited antibodies against JO4 that increased with each cycle and were accompanied by elevation of pro-inflammatory cytokines IL6 and TNF. Pretreatment with steroids and cyclophosphamide reduced the anti-JO4 antibody response and blunted cytokine release. Our data indicate acceptable safety of our new treatment approach if immune reactions are monitored and counteracted with appropriate immune suppression.

Skin-on-a-Chip Technology for Testing Transdermal Drug Delivery—Starting Points and Recent Developments

During the last decades, several technologies were developed for testing drug delivery through the dermal barrier. Investigation of drug penetration across the skin can be important in topical pharmaceutical formulations and also in cosmeto-science. The state-of- the-art in the field of skin diffusion measurements, different devices, and diffusion platforms used, are summarized in the introductory part of this review. Then the methodologies applied at Pázmány Péter Catholic University are shown in detail. The main testing platforms (Franz diffusion cells, skin-on-a-chip devices) and the major scientific projects (P-glycoprotein interaction in the skin; new skin equivalents for diffusion purposes) are also presented in one section. The main achievements of our research are briefly summarized: (1) new skin-on-a-chip microfluidic devices were validated as tools for drug penetration studies for the skin; (2) P-glycoprotein transport has an absorptive orientation in the skin; (3) skin samples cannot be used for transporter interaction studies after freezing and thawing; (4) penetration of hydrophilic model drugs is lower in aged than in young skin; (5) mechanical sensitization is needed for excised rodent and pig skins for drug absorption measurements. Our validated skin-on-a-chip platform is available for other research groups to use for testing and for utilizing it for different purposes.

EXTH-64. COMPARISON OF PANOBINOSTAT CSF PENETRATION WITH CNS PENETRATION FOLLOWING SYSTEMIC ADMINISTRATION IN A PRE-CLINICAL NON-HUMAN PRIMATE MODEL

Targeted therapies developed for diffuse midline gliomas (DMG) expressing H3K27M have focused on histone deacetylase inhibitors (HDACi). High-throughput drug screening with patient derived DMG cell lines identified the HDACi panobinostat as a prominent clinical agent as well as pre-clinical studies with orthotopic mouse tumors models proving efficacious. Diametrically there is a pronounced lack of measurable panobinostat CSF concentrations in a non-human primate (NHP) non-tumor bearing pre-clinical model and in pediatric brain tumor patients. Notwithstanding, adult and pediatric glioma clinical trials and clinical observation with panobinostat alone or in combination have demonstrated minor responses. Pharmacokinetic models utilize the premise that CSF drug penetration is a surrogate of CNS drug penetration. However, the direct correlation between CSF and CNS drug levels is undefined especially in lieu of geographic CNS extracellular fluid drug variability previously demonstrated in the same NHP pre-clinical model. Utilizing the same NHP model, this study sought to compare panobinostat CSF penetration to CNS penetration via analysis of homogenized normal cerebrum, cerebellum, and brainstem tissue utilizing LC-MS/MS. METHODS: Panobinostat was administered orally as a single dose to three non-human primates. Pre panobinostat plasma and CSF were collected. Following panobinostat administration (1-hr Tmax) CSF, cerebrum, cerebellum, and brain stem tissue were collected as well as plasma to confirm the presence of panobinostat. Tissue slices were individually homogenized and panobinostat extracted via protein precipitation. Plasma, CSF, and tissue panobinostat concentrations were quantified using a LC-MS/MS assay. The lower limit of quantitation (LLOQ) for plasma-0.1 ng/ml, CSF-0.5 ng/ml, and tissue-10.0 pg/mg. RESULTS: Panobinostat was quantifiable in plasma (n=2) at the 1 hour (20.033 ng/mL and 0.153 ng/mL). CSF and CNS tissue samples were below the LLOQ for panobinostat in all samples. CONCLUSIONS: Panobinostat was not measurable from CSF and homogenized brain tissue in a non-tumor bearing NHP model at 1-hour post-administration using LC-MS/MS.

New Approaches to Glioblastoma

Faced with unique immunobiology and marked heterogeneity, treatment strategies for glioblastoma require therapeutic approaches that diverge from conventional oncological strategies. The selection and prioritization of targeted and immunotherapeutic strategies will need to carefully consider these features and companion biomarkers developed alongside treatment strategies to identify the appropriate patient populations. Novel clinical trial strategies that interrogate the tumor microenvironment for drug penetration and target engagement will inform go/no-go later-stage clinical studies. Innovative trial designs and analyses are needed to move effective agents toward regulatory approvals more rapidly. Expected final online publication date for the Annual Review of Medicine, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Drug Penetration into the Central Nervous System: Pharmacokinetic Concepts and In Vitro Model Systems

Delivery of most drugs into the central nervous system (CNS) is restricted by the blood–brain barrier (BBB), which remains a significant bottleneck for development of novel CNS-targeted therapeutics or molecular tracers for neuroimaging. Consistent failure to reliably predict drug efficiency based on single measures for the rate or extent of brain penetration has led to the emergence of a more holistic framework that integrates data from various in vivo, in situ and in vitro assays to obtain a comprehensive description of drug delivery to and distribution within the brain. Coupled with ongoing development of suitable in vitro BBB models, this integrated approach promises to reduce the incidence of costly late-stage failures in CNS drug development, and could help to overcome some of the technical, economic and ethical issues associated with in vivo studies in animal models. Here, we provide an overview of BBB structure and function in vivo, and a summary of the pharmacokinetic parameters that can be used to determine and predict the rate and extent of drug penetration into the brain. We also review different in vitro models with regard to their inherent shortcomings and potential usefulness for development of fast-acting drugs or neurotracers labeled with short-lived radionuclides. In this regard, a special focus has been set on those systems that are sufficiently well established to be used in laboratories without significant bioengineering expertise.

Impact of Alkanediols on Stratum Corneum Lipids and Triamcinolone Acetonide Skin Penetration

Alkanediols are widely used as multifunctional ingredients in dermal formulations. In addition to their preservative effect, considering their possible impact on drug penetration is also essential for their use. In the present study, the influence of 2-methyl-2,4-pentanediol, 1,2-pentanediol, 1,2-hexanediol and 1,2-octanediol on the skin penetration of triamcinolone acetonide from four different semisolid formulations was investigated. Furthermore, confocal Raman spectroscopy measurements were performed to examine the influence of the alkanediols on stratum corneum lipid content and order. Alkanediols were found to increase the penetration of triamcinolone acetonide. However, the extent depends strongly on the formulation used. In certain formulations, 1,2-pentanediol showed the highest effect, while in others the penetration-enhancing effect increased with the alkyl chain length of the alkanediol used. None of the tested alkanediols extracted lipids from the stratum corneum nor reduced its thickness. Notwithstanding the above, the longer-chained alkanediols cause the lipids to be converted to a more disordered state, which favors drug penetration. This behavior could not be detected for the shorter-chained alkanediols. Therefore, their penetration-enhancing effect is supposed to be related to an interaction with the hydrophilic regions of the stratum corneum.

The Extracellular Matrix in Pancreatic Cancer: Description of a Complex Network and Promising Therapeutic Options

The stroma is a relevant player in driving and supporting the progression of pancreatic ductal adenocarcinoma (PDAC), and a large body of evidence highlights its role in hindering the efficacy of current therapies. In fact, the dense extracellular matrix (ECM) characterizing this tumor acts as a natural physical barrier, impairing drug penetration. Consequently, all of the approaches combining stroma-targeting and anticancer therapy constitute an appealing option for improving drug penetration. Several strategies have been adopted in order to target the PDAC stroma, such as the depletion of ECM components and the targeting of cancer-associated fibroblasts (CAFs), which are responsible for the increased matrix deposition in cancer. Additionally, the leaky and collapsing blood vessels characterizing the tumor might be normalized, thus restoring blood perfusion and allowing drug penetration. Even though many stroma-targeting strategies have reported disappointing results in clinical trials, the ECM offers a wide range of potential therapeutic targets that are now being investigated. The dense ECM might be bypassed by implementing nanoparticle-based systems or by using mesenchymal stem cells as drug carriers. The present review aims to provide an overview of the principal mechanisms involved in the ECM remodeling and of new promising therapeutic strategies for PDAC.