The oral nucleoside prodrug GS-5245 is efficacious against SARS-CoV-2 and other endemic, epidemic, and enzootic coronaviruses.

Despite the wide availability of several safe and effective vaccines that prevent severe COVID-19, the persistent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) that can evade vaccine-elicited immunity remains a global health concern. In addition, the emergence of SARS-CoV-2 VOCs that can evade therapeutic monoclonal antibodies underscores the need for additional, variant-resistant treatment strategies. Here, we characterize the antiviral activity of GS-5245, obeldesivir (ODV), an oral prodrug of the parent nucleoside GS-441524, which targets the highly conserved viral RNA-dependent RNA polymerase (RdRp). We show that GS-5245 is broadly potent in vitro against alphacoronavirus HCoV-NL63, SARS-CoV, SARS-CoV-related bat-CoV RsSHC014, Middle East respiratory syndrome coronavirus (MERS-CoV), SARS-CoV-2 WA/1, and the highly transmissible SARS-CoV-2 BA.1 Omicron variant. Moreover, in mouse models of SARS-CoV, SARS-CoV-2 (WA/1 and Omicron B1.1.529), MERS-CoV, and bat-CoV RsSHC014 pathogenesis, we observed a dose-dependent reduction in viral replication, body weight loss, acute lung injury, and pulmonary function with GS-5245 therapy. Last, we demonstrate that a combination of GS-5245 and main protease (Mpro) inhibitor nirmatrelvir improved outcomes in vivo against SARS-CoV-2 compared with the single agents. Together, our data support the clinical evaluation of GS-5245 against coronaviruses that cause or have the potential to cause human disease.

Participation of suicide gene extracellular vesicles in metastasis prevention.

The incidence of distant metastases is associated with most cancer-related mortalities. Extracellular vesicles (EVs), secreted from tumors and cancer-associated fibroblasts, are involved in the metastatic process mediating their organotropism through their involvement in the pre-metastatic niche formation. We have been developing suicide gene therapy mediated by EVs secreted from mesenchymal stem/ stromal cells, tumor cells, and cancer-associated fibroblasts. Suicide gene EVs conjugated with prodrug are tumor tropic, penetrate tumor cells, and kill them by intracellular conversion of nontoxic prodrug to an efficient anti-cancer drug. Here, we discuss findings regarding the possibility of using suicide gene EVs as a novel therapeutic approach for metastases, via pre-metastatic niche modification. The suicide gene EVs provide a future perspective for metastasis prevention.

Self-Assembled Nanoparticles from the Amphiphilic Prodrug of Resiquimod for Improved Cancer Immunotherapy.

Tumor-associated macrophages (TAMs) usually adopt a tumor-promoting M2-like phenotype, which largely impedes the immune response and therapeutic efficacy of solid tumors. Repolarizing TAMs from M2 to the antitumor M1 phenotype is crucial for reshaping the tumor immunosuppressive microenvironment (TIME). Herein, we developed self-assembled nanoparticles from the polymeric prodrug of resiquimod (R848) to reprogram the TIME for robust cancer immunotherapy. The polymeric prodrug was constructed by conjugating the R848 derivative to terminal amino groups of the linear dendritic polymer composed of linear poly(ethylene glycol) and lysine dendrimer. The amphiphilic prodrug self-assembled into nanoparticles (PLRS) of around 35 nm with a spherical morphology. PLRS nanoparticles could be internalized by antigen-presenting cells (APCs) in vitro and thus efficiently repolarized macrophages from M2 to M1 and facilitated the maturation of APCs. In addition, PLRS significantly inhibited tumor growth in the 4T1 orthotopic breast cancer model with much lower systemic side effects. Mechanistic studies suggested that PLRS significantly stimulated the TIME by repolarizing TAMs into the M1 phenotype and increased the infiltration of cytotoxic T cells into the tumor. This study provides an effective polymeric prodrug-based strategy to improve the therapeutic efficacy of R848 in cancer immunotherapy.

Tumor-Targeted Oxaliplatin(IV) Prodrug Delivery Based on ROS-Regulated Cancer-Selective Glycan Labeling.

Platinum-drug-based chemotherapy in clinics has achieved great success in clinical malignancy therapy. However, unpredictable off-target toxicity and the resulting severe side effects in the treatment are still unsolved problems. Although metabolic glycan labeling-mediated tumor-targeted therapy has been widely reported, less selective metabolic labeling in vivo limited its wide application. Herein, a novel probe of B-Ac3ManNAz that is regulated by reactive oxygen species in tumor cells is introduced to enhance the recognition and cytotoxicity of DBCO-modified oxaliplatin(IV) via bioorthogonal chemistry. B-Ac3ManNAz was synthesized from Ac4ManNAz by incorporation with 4-(hydroxymethyl) benzeneboronic acid pinacol ester (HBAPE) at the anomeric position, which is confirmed to be regulated by ROS and could robustly label glycans on the cell surface. Moreover, N3-treated tumor cells could enhance the tumor accumulation of DBCO-modified oxaliplatin(IV) via click chemistry meanwhile reduce the off-target distribution in normal tissue. Our strategy provides an effective metabolic precursor for tumor-specific labeling and targeted cancer therapies.

Tumor Microenvironment Modulates Invadopodia Activity of Non-Selected and Acid-Selected Pancreatic Cancer Cells and Its Sensitivity to Gemcitabine and C18-Gemcitabine.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease with high mortality due to early metastatic dissemination and high chemoresistance. All these factors are favored by its extracellular matrix (ECM)-rich microenvironment, which is also highly hypoxic and acidic. Gemcitabine (GEM) is still the first-line therapy in PDAC. However, it is quickly deaminated to its inactive metabolite. Several GEM prodrugs have emerged to improve its cytotoxicity. Here, we analyzed how the acidic/hypoxic tumor microenvironment (TME) affects the response of PDAC cell death and invadopodia-mediated ECM proteolysis to both GEM and its C18 prodrug. METHODS: For this, two PDAC cell lines, PANC-1 and Mia PaCa-2 were adapted to pHe 6.6 or not for 1 month, grown as 3D organotypic cultures and exposed to either GEM or C18 in the presence and absence of acidosis and the hypoxia inducer, deferoxamine. RESULTS: We found that C18 has higher cytotoxic and anti-invadopodia activity than GEM in all culture conditions and especially in acid and hypoxic environments. CONCLUSIONS: We propose C18 as a more effective approach to conventional GEM in developing new therapeutic strategies overcoming PDAC chemoresistance.

Simultaneous targeting of peripheral and brain tumors with a therapeutic nanoparticle to disrupt metabolic adaptability at both sites.

Brain metastasis of advanced breast cancer often results in deleterious consequences. Metastases to the brain lead to significant challenges in treatment options, as the blood-brain barrier (BBB) prevents conventional therapy. Thus, we hypothesized that creation of a nanoparticle (NP) that distributes to both primary tumor site and across the BBB for secondary brain tumor can be extremely beneficial. Here, we report a simple targeting strategy to attack both the primary breast and secondary brain tumors utilizing a single NP platform. The nature of these mitochondrion-targeted, BBB-penetrating NPs allow for simultaneous targeting and drug delivery to the hyperpolarized mitochondrial membrane of the extracranial primary tumor site in addition to tumors at the brain. By utilizing a combination of such dual anatomical distributing NPs loaded with therapeutics, we demonstrate a proof-of-concept idea to combat the increased metabolic plasticity of brain metastases by lowering two major energy sources, oxidative phosphorylation (OXPHOS) and glycolysis. By utilizing complementary studies and genomic analyses, we demonstrate the utility of a chemotherapeutic prodrug to decrease OXPHOS and glycolysis by pairing with a NP loaded with pyruvate dehydrogenase kinase 1 inhibitor. Decreasing glycolysis aims to combat the metabolic flexibility of both primary and secondary tumors for therapeutic outcome. We also address the in vivo safety parameters by addressing peripheral neuropathy and neurobehavior outcomes. Our results also demonstrate that this combination therapeutic approach utilizes mitochondrial genome targeting strategy to overcome DNA repair-based chemoresistance mechanisms.

Disulfide/α-Amide-Bridged Doxorubicin Dimeric Prodrug: Effect of Aggregation Structures on pH/GSH Dual-Triggered Drug Release.

Disulfide bonding has attracted intense interest in the tumor intracellular microenvironment-activated drug delivery systems (DDSs) in the last decades. Although various molecular structures of redox-responsive disulfide-containing DDSs have been developed, no investigation was reported on the effect of aggregation structures. Here, the effect of aggregation structures on pH/GSH dual-triggered drug release was investigated with the simplest pH/GSH dual-triggered doxorubicin-based drug self-delivery system (DSDS), the disulfide/α-amide-bridged doxorubicin dimeric prodrug (DDOX), as a model. By fast precipitation or slow self-assembly, DDOX nanoparticles were obtained. With similar diameters, they exhibited different pH/GSH dual-triggered drug releases, demonstrating the effect of aggregation structures. The π-π stacking in different degrees was revealed by the UV-vis, fluorescence, and BET analysis of the DDOX nanoparticles. The effect of the π-π stacking between the dimeric prodrug and its activated products on drug release was also explored with the molecular simulation approach. The finding opens new ideas in the design of high-performance DDSs for future precise tumor treatment.

Endowing Pt(IV) with Perfluorocarbon Chains and Human Serum Albumin Encapsulation for Highly Effective Antitumor Chemoimmunotherapy.

Tumor metastases and reoccurrence are considered the leading causes of cancer-associated deaths. As an emerging therapeutic method, increasing research efforts have been devoted to immunogenic cell death (ICD)-inducing compounds to solve the challenge. The clinically approved chemotherapeutic Pt complexes are not or are only poorly able to trigger ICD. Herein, the axial functionalization of the Pt(II) complex cisplatin with perfluorocarbon chains into ICD-inducing Pt(IV) prodrugs is reported. Strikingly, while the Pt(II) complex as well as the perfluorocarbon ligands did not induce ICD, the Pt(IV) prodrug demonstrated unexpectantly the induction of ICD through accumulation in the endoplasmic reticulum and generation of reactive oxygen species in this organelle. To enhance the pharmacological properties, the compound was encapsulated with human serum albumin into nanoparticles. While selectively accumulating in the tumorous tissue, the nanoparticles demonstrated a strong tumor growth inhibitory effect against osteosarcoma inside a mouse model. In vivo tumor vaccine analysis also demonstrated the ability of Pt(IV) to be an ideal ICD inducer. Overall, this study reports on axially perfluorocarbon chain-modified Pt(IV) complexes for ICD induction and chemoimmunotherapy in osteosarcoma.

Prodrug-conjugated tumor-seeking commensals for targeted cancer therapy.

Prodrugs have been explored as an alternative to conventional chemotherapy; however, their target specificity remains limited. The tumor microenvironment harbors a range of microorganisms that potentially serve as tumor-targeting vectors for delivering prodrugs. In this study, we harness bacteria-cancer interactions native to the tumor microbiome to achieve high target specificity for prodrug delivery. We identify an oral commensal strain of Lactobacillus plantarum with an intrinsic cancer-binding mechanism and engineer the strain to enable the surface loading of anticancer prodrugs, with nasopharyngeal carcinoma (NPC) as a model cancer. The engineered commensals show specific binding to NPC via OppA-mediated recognition of surface heparan sulfate, and the loaded prodrugs are activated by tumor-associated biosignals to release SN-38, a chemotherapy compound, near NPC. In vitro experiments demonstrate that the prodrug-loaded microbes significantly increase the potency of SN-38 against NPC cell lines, up to 10-fold. In a mouse xenograft model, intravenous injection of the engineered L. plantarum leads to bacterial colonization in NPC tumors and a 67% inhibition in tumor growth, enhancing the efficacy of SN-38 by 54%.

Exploring the physicochemical properties of the integration of Tristearoyl uridine in Langmuir monolayers: An approach to cell membrane modeling for prodrugs.

Understanding the mechanisms by which drugs interact with cell membranes is crucial for unraveling the underlying biochemical and biophysical processes that occur on the surface of these membranes. Our research focused on studying the interaction between an ester-type derivative of tristearoyl uridine and model cell membranes composed of lipid monolayers at the air-water interface. For that, we selected a specific lipid to simulate nontumorigenic cell membranes, namely 1,2-dihexadecanoyl-sn-glycero-3-phospho-l-serine. We noted significant changes in the surface pressure-area isotherms, with a noticeable shift towards larger areas, which was lower than expected for ideal mixtures, indicating monolayer condensation. Furthermore, the viscoelastic properties of the interfacial film demonstrated an increase in both the elastic and viscous parameters for the mixed film. We also observed structural alterations using vibrational spectroscopy, which revealed an increase in the all-trans to gauche conformers ratio. This confirmed the stiffening effect of the prodrug on the lipid monolayer. In summary, this study indicates that this lipophilic prodrug significantly impacts the lipid monolayer's thermodynamic, rheological, electrical, and molecular characteristics. This information is crucial for understanding how the drug interacts with specific sites on the cellular membrane. It also has implications for drug delivery, as the drug's passage into the cytosol may involve traversing the lipid bilayer.

Supramolecular prodrug of SN38 based on endogenous albumin and SN38 prodrug modified with semaglutide side chain to improve the tumor distribution.

To improve the biodistribution of the drug in the tumor, a supramolecular prodrug of SN38 was fabricated in situ between endogenous albumin and SN38 prodrug modified with semaglutide side chain. Firstly, SN38 was conjugated with semaglutide side chain and octadecanedioic acid via glycine linkers to obtain SI-Gly-SN38 and OA-Gly-SN38 prodrugs, respectively. Both SI-Gly-SN38 and OA-Gly-SN38 exhibited excellent stability in PBS for over 24 h. Due to the strong binding affinity of the semaglutide side chain with albumin, the plasma half-life of SI-Gly-SN38 was 2.7 times higher than that of OA-Gly-SN38. Furthermore, with addition of HSA, the fluorescence intensity of SI-Gly-SN38 was 4 times higher than that of OA-Gly-SN38, confirming its strong binding capability with HSA. MTT assay showed that the cytotoxicity of SI-Gly-SN38 and OA-Gly-SN38 was higher than that of Irinotecan. Even incubated with HSA, the SI-Gly-SN38 and OA-Gly-SN38 still maintained high cytotoxicity, indicating minimal influence of HSA on their cytotoxicity. In vivo pharmacokinetic studies demonstrated that the circulation half-life of SI-Gly-SN38 was twice that of OA-Gly-SN38. SI-Gly-SN38 exhibited significantly reduced accumulation in the lungs, being only 0.23 times that of OA-Gly-SN38. The release of free SN38 in the lungs from SI-Gly-SN38 was only 0.4 times that from OA-Gly-SN38 and Irinotecan. The SI-Gly-SN38 showed the highest accumulation in tumors. The tumor inhibition rate of SI-Gly-SN38 was 6.42% higher than that of OA-Gly-SN38, and 8.67% higher than that of Irinotecan, respectively. These results indicate that the supramolecular prodrug delivery system can be constructed between SI-Gly-SN38 and endogenous albumin, which improves drug biodistribution in vivo, enhances tumor accumulation, and plays a crucial role in tumor growth inhibition.

Non-canonical substrate recognition by the human WDR26-CTLH E3 ligase regulates prodrug metabolism.

The yeast glucose-induced degradation-deficient (GID) E3 ubiquitin ligase forms a suite of complexes with interchangeable receptors that selectively recruit N-terminal degron motifs of metabolic enzyme substrates. The orthologous higher eukaryotic C-terminal to LisH (CTLH) E3 complex has been proposed to also recognize substrates through an alternative subunit, WDR26, which promotes the formation of supramolecular CTLH E3 assemblies. Here, we discover that human WDR26 binds the metabolic enzyme nicotinamide/nicotinic-acid-mononucleotide-adenylyltransferase 1 (NMNAT1) and mediates its CTLH E3-dependent ubiquitylation independently of canonical GID/CTLH E3-family substrate receptors. The CTLH subunit YPEL5 inhibits NMNAT1 ubiquitylation and cellular turnover by WDR26-CTLH E3, thereby affecting NMNAT1-mediated metabolic activation and cytotoxicity of the prodrug tiazofurin. Cryoelectron microscopy (cryo-EM) structures of NMNAT1- and YPEL5-bound WDR26-CTLH E3 complexes reveal an internal basic degron motif of NMNAT1 essential for targeting by WDR26-CTLH E3 and degron mimicry by YPEL5's N terminus antagonizing substrate binding. Thus, our data provide a mechanistic understanding of how YPEL5-WDR26-CTLH E3 acts as a modulator of NMNAT1-dependent metabolism.

Unveiling the potential of ursolic acid modified hyaluronate nanoparticles for combination drug therapy in triple negative breast cancer.

Triple negative breast cancer (TNBC) represents the most aggressive and heterogenous disease, and combination therapy holds promising potential. Here, an enzyme-responsive polymeric prodrug with self-assembly properties was synthesized for targeted co-delivery of paclitaxel (PTX) and ursolic acid (UA). Hyaluronic acid (HA) was conjugated with UA, yielding an amphiphilic prodrug with 13.85 mol% UA and a CMC of 32.3 µg/mL. The HA-UA conjugate exhibited ∼14 % and 47 % hydrolysis at pH 7.4 and in tumor cell lysate. HA-UA/PTX NPs exhibited a spherical structure with 173 nm particle size, and 0.15 PDI. The nanoparticles showed high drug loading (11.58 %) and entrapment efficiency (76.87 %) of PTX. Release experiments revealed accelerated drug release (∼78 %) in the presence of hyaluronidase enzyme. Cellular uptake in MDA-MB-231 cells showed enhanced uptake of HA-UA/PTX NPs through CD44 receptor-mediated endocytosis. In vitro, HA-UA/PTX NPs exhibited higher cytotoxicity, apoptosis, and mitochondrial depolarization compared to PTX alone. In vivo, HA-UA/PTX NPs demonstrated improved pharmacokinetic properties, with 2.18, 2.40, and 2.35-fold higher AUC, t1/2, and MRT compared to free PTX. Notably, HA-UA/PTX NPs exhibited superior antitumor efficacy with a 90 % tumor inhibition rate in 4T1 tumor model and low systemic toxicity, showcasing their significant potential as carriers for TNBC combination therapy.

Light-Responsive Pt(IV) Prodrugs with Controlled Photoactivation and Low Dark Toxicity.

Light-induced release of cisplatin from Pt(IV) prodrugs represents a promising approach for precise control over the antiproliferative activity of Pt-based chemotherapeutic drugs. This method has the potential to overcome crucial drawbacks of conventional cisplatin therapy, such as high general toxicity toward healthy organs and tissues. Herein, we report two Pt(IV) prodrugs with BODIPY-based photoactive ligands Pt-1 and Pt-2, which were designed using carbamate and triazole linkers, respectively. Both prodrugs demonstrated the ability to release cisplatin under blue light irradiation without the requirement of an external reducing agent. Dicarboxylated Pt-2 prodrug turned out to be more stable in the dark and more sensitive to light than its monocarbamate Pt-1 counterpart; these observations were explained using DFT calculations. The investigation of the photoreduction mechanism of Pt-1 and Pt-2 prodrugs using DFT modeling and ΔG0 PET estimation suggests that the photoinduced electron transfer from the singlet excited state of the BODIPY axial ligand to the Pt(IV) center is the key step in the light-induced release of cisplatin from the complexes. Cytotoxicity studies demonstrated that both prodrugs were nontoxic in the dark and toxic to MCF-7 cells under low-dose irradiation with blue light, and the observed effect was solely due to the cisplatin release from the Pt(IV) prodrugs. Our research presents an elegant synthetic approach to light-activated Pt(IV) prodrugs and presents findings that may contribute to the future rational design of photoactivatable Pt(IV) prodrugs.

Glutathione-depleting polyprodrug nanoparticle for enhanced photodynamic therapy and cascaded locoregional chemotherapy.

Nanomedicines that combine reactive oxygen species (ROS)-responsive polyprodrug and photodynamic therapy have shown great potential for improving treatment efficacy. However, the consumption of ROS by overexpressed glutathione in tumor cells is a major obstacle for achieving effective ROS amplification and prodrug activation. Herein, we report a polyprodrug-based nanoparticle that can realize ROS amplification and cascaded drug release. The nanoparticle can respond to the high level of hydrogen peroxide in tumor microenvironment, achieving self-destruction and release of quinone methide. The quinone methide depletes intracellular glutathione and thus decreases the antioxidant capacity of cancer cells. Under laser irradiation, a large amount of ROS will be generated to induce cell damage and prodrug activation. Therefore, the glutathione-depleting polyprodrug nanoparticles can efficiently inhibit tumor growth by enhanced photodynamic therapy and cascaded locoregional chemotherapy.

Polyprodrug nanomedicine for chemiexcitation-triggered self-augmented cancer chemotherapy and gas therapy.

Carbon monoxide (CO) has emerged as a potential antitumor agent by inducing the dysfunction of mitochondria and the apoptosis of cancer cells. However, it remains challenging to deliver appropriate amount of CO into tumor to ensure efficient tumor growth suppression with minimum side effects. Herein we developed a CO prodrug-loaded nanomedicine based on the self-assembly of camptothecin (CPT) polyprodrug amphiphiles. The polyprodrug nanoparticles readily dissociate upon exposure to endogenous H2O2 in the tumor, resulting in rapid release of CPT and generation of high-energy intermediate dioxetanedione. The latter can transfer the energy to neighboring CO prodrugs to activate CO production by chemiexcitation, while CPT promotes the generation of H2O2 in tumors, which in turn facilitates cascade CPT and CO release. As a result, the polyprodrug nanoparticles display remarkable tumor suppression in both subcutaneous and orthotopic breast tumor-bearing mice owing to the self-augmented CPT release and CO generation. In addition, no obvious systemic toxicity was observed in mice treated with the metal-free CO prodrug-loaded nanomedicine, suggesting the good biocompatibility of the polyprodrug nanoparticles. Our work provides new insights into the design and construction of polyprodrug nanomedicines for synergistic chemo/gas therapy.

Multiple drug-delivery strategies to enhance the pharmacological and toxicological properties of Mefenamic acid.

OBJECTIVE: To improve the biological and toxicological properties of Mefenamic acid (MA), the galactosylated prodrug of MA named MefeGAL was included in polymeric solid dispersions (PSs) composed of poly(glycerol adipate) (PGA) and Pluronic® F68 (MefeGAL-PS). MefeGAL-PS was compared with polymeric solid formulations of MA (MA-PS) or a mixture of equal ratio of MefeGAL/MA (Mix-PS). METHODS: The in vitro and in vivo pharmacological and toxicological profiles of PSs have been investigated. In detail, we evaluated the anti-inflammatory (carrageenan-induced paw edema test), analgesic (acetic acid-induced writhing test) and ulcerogenic activity in mice after oral treatment. Additionally, the antiproliferative activity of PSs was assessed on in vitro models of colorectal and non-small cell lung cancer. RESULTS: When the PSs were resuspended in water, MefeGAL's, MA's and their mixture's apparent solubilities improved due to the interaction with the polymeric formulation. By comparing the in-vivo biological performance of MefeGAL-PS with that of MA, MefeGAL and MA-PS, it was seen that MefeGAL-PS exhibited the same sustained and delayed analgesic and anti-inflammatory profile as MefeGAL but did not cause gastrointestinal irritation. The pharmacological effect of Mix-PS was present from the first hours after administration, lasting about 44 hours with only slight gastric mucosa irritation. In-vitro evaluation indicated that Mix-PS had statistically significant higher cytotoxicity than MA-PS and MefeGAL-PS. CONCLUSIONS: These preliminary data are promising evidence that the galactosylated prodrug approach in tandem with a polymer-drug solid dispersion formulation strategy could represent a new drug delivery route to improve the solubility and biological activity of NSAIDs.

Evaluation of Pharmacokinetics of a BCS Class III Drug with Two Different Study Designs: Tenofovir Alafenamide Monofumarate Film-coated Tablet.

Tenofovir alafenamide (TAF) is a BCS Class III compound and an oral pro-drug of Tenofovir (TFV) with limited oral bioavailability. The bioavailability of the oral intake increases with food as a result of the low stability of the active substance in the stomach. The reference drug is "Vemlidy® 25 mg Film Tablet", which contains 25 mg of TAF in "hemifumarate" form, is under patent protection until 15.08.2032 by Gilead, and so the "monofumarate" form was used in the present study. At first, a pilot study was conducted involving 12 subjects under fed conditions. The results of the pilot study revealed the test and reference products were not bioequivalent, as a result of insufficient statistical power and high inter-subject variability. Secondly, a physiologically based pharmacokinetic (PBPK) simulation was performed based on the pilot study results and literature data. Finally, the power of the design was increased and the pivotal study design was optimized into a four-period, full-replicated, cross-over study with 34 subjects under fed conditions and it was concluded that the test and reference products were bioequivalent. In conclusion, the present study proved the importance of a correct study design with higher statistical power for a BCS Class III compound with high variability, to present the pharmacokinetics.

Differential Bioactivation Profiles of Different GS-441524 Prodrugs in Cell and Mouse Models: ProTide Prodrugs with High Cell Permeability and Susceptibility to Cathepsin A Are More Efficient in Delivering Antiviral Active Metabolites to the Lung.

We assessed factors that determine the tissue-specific bioactivation of ProTide prodrugs by comparing the disposition and activation of remdesivir (RDV), its methylpropyl and isopropyl ester analogues (MeRDV and IsoRDV, respectively), the oral prodrug GS-621763, and the parent nucleotide GS-441524 (Nuc). RDV and MeRDV yielded more active metabolite remdesivir-triphosphate (RDV-TP) than IsoRDV, GS-621763, and Nuc in human lung cell models due to superior cell permeability and higher susceptivity to cathepsin A. Intravenous administration to mice showed that RDV and MeRDV delivered significantly more RDV-TP to the lung than other compounds. Nevertheless, all four ester prodrugs exhibited very low oral bioavailability (<2%), with Nuc being the predominant metabolite in blood. In conclusion, ProTides prodrugs, such as RDV and MeRDV, are more efficient in delivering active metabolites to the lung than Nuc, driven by high cell permeability and susceptivity to cathepsin A. Optimizing ProTides' ester structures is an effective strategy for enhancing prodrug activation in the lung.

Protocol for a seamless phase 2A-phase 2B randomized double-blind placebo-controlled trial to evaluate the safety and efficacy of benfotiamine in patients with early Alzheimer's disease (BenfoTeam).

BACKGROUND: Benfotiamine provides an important novel therapeutic direction in Alzheimer's disease (AD) with possible additive or synergistic effects to amyloid targeting therapeutic approaches. OBJECTIVE: To conduct a seamless phase 2A-2B proof of concept trial investigating tolerability, safety, and efficacy of benfotiamine, a prodrug of thiamine, as a first-in-class small molecule oral treatment for early AD. METHODS: This is the protocol for a randomized, double-blind, placebo-controlled 72-week clinical trial of benfotiamine in 406 participants with early AD. Phase 2A determines the highest safe and well-tolerated dose of benfotiamine to be carried forward to phase 2B. During phase 2A, real-time monitoring of pre-defined safety stopping criteria in the first approximately 150 enrollees will help determine which dose (600 mg or 1200 mg) will be carried forward into phase 2B. The phase 2A primary analysis will test whether the rate of tolerability events (TEs) is unacceptably high in the high-dose arm compared to placebo. The primary safety endpoint in phase 2A is the rate of TEs compared between active and placebo arms, at each dose. The completion of phase 2A will seamlessly transition to phase 2B without pausing or stopping the trial. Phase 2B will assess efficacy and longer-term safety of benfotiamine in a larger group of participants through 72 weeks of treatment, at the selected dose. The co-primary efficacy endpoints in phase 2B are CDR-Sum of Boxes and ADAS-Cog13. Secondary endpoints include safety and tolerability measures; pharmacokinetic measures of thiamine and its esters, erythrocyte transketolase activity as blood markers of efficacy of drug delivery; ADCS-ADL-MCI; and MoCA. CONCLUSION: The BenfoTeam trial utilizes an innovative seamless phase 2A-2B design to achieve proof of concept. It includes an adaptive dose decision rule, thus optimizing exposure to the highest and best-tolerated dose. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT06223360, registered on January 25, 2024. https://classic.clinicaltrials.gov/ct2/show/NCT06223360.