Pharmacokinetics of the Monocarboxylate Transporter 1 Inhibitor AZD3965 in Mice: Potential Enterohepatic Circulation and Target-Mediated Disposition

Importance of Considering Fed-State Gastrointestinal Physiology in Predicting the Reabsorption of Enterohepatic Circulation of Drugs

PURPOSE

The purpose of this study was to develop a simulation model for the pharmacokinetics (PK) of drugs undergoing enterohepatic circulation (EHC) with consideration to the environment in the gastrointestinal tract in the fed state in humans. The investigation particularly focused on the necessity of compensating for the permeability rate constant in the reabsorption process in consideration of drug entrapment in bile micelles.

METHODS

Meloxicam and ezetimibe were used as model drugs. The extent of the entrapment of drugs inside bile micelles was evaluated using the solubility ratio of Fed State Simulated Intestinal Fluid version 2 (FeSSIF-V2) to Fasted State Simulated Intestinal Fluid version 2 (FaSSIF-V2). Prediction accuracy was evaluated using the Mean Absolute Percentage Error (MAPE) value, calculated from the observed and predicted oral PK profiles.

RESULTS

The solubilization of ezetimibe by bile micelles was clearly observed while that of meloxicam was not. Assuming that only drugs in the free fraction of micelles permeate through the intestinal membrane, PK simulation for ezetimibe was performed in both scenarios with and without compensation by the permeation rate constant. The MAPE value of Zetia® tablet, containing ezetimibe, was lower with compensation than without compensation. By contrast, Mobic® tablet, containing meloxicam, showed a relatively low MAPE value even without compensation.

CONCLUSION

For drugs which undergo EHC and can be solubilized by bile micelles, compensating for the permeation rate constant in the reabsorption process based on the free fraction ratio appears an important factor in increasing the accuracy of PK profile prediction.

Heterocyclic and non-heterocyclic arena of monocarboxylate transporter inhibitors to battle tumorigenesis

Monocarboxylate transporters (MCTs) have gained significant attention in cancer research due to their critical role in tumour metabolism. MCTs are legends for transporting lactate molecules in cancer cells, an oncometabolite and waste product of glycolysis, acting as an indispensable factor of tumour proliferation. Targeting MCTs with inhibitors has emerged as a promising strategy to combat tumorigenesis. This article summarizes the most recent research on MCT inhibitors in preventing carcinogenesis, covering both heterocyclic and non-heterocyclic compounds. Heterocyclic and non-heterocyclic compounds such as pteridine, pyrazole, indole, flavonoids, coumarin derivatives and cyanoacetic acid derivatives have been reported as potent MCT inhibitors. We examine the molecular underpinnings of MCTs in cancer metabolism, the design and synthesis of heterocyclic and non-heterocyclic MCT inhibitors, their impact on tumour cells and the microenvironment and their potential as therapeutic agents. Moreover, we explore the challenges associated with MCT inhibitor development and propose future directions for advancing this field. This write-up aims to provide researchers, scientists and clinicians with a comprehensive understanding of the heterocyclic and non-heterocyclic MCT inhibitors and their potential in combating tumorigenesis.

Selective Blood Cell Hitchhiking in Whole Blood with Ionic Liquid-Coated PLGA Nanoparticles to Redirect Biodistribution After Intravenous Injection

Less than 5% of intravenously-injected nanoparticles (NPs) reach destined sites in the body due to opsonization and immune-based clearance in vascular circulation. By hitchhiking in situ onto specific blood components post-injection, NPs can selectively target tissue sites for unprecedentedly high drug delivery rates. Choline carboxylate ionic liquids (ILs) are biocompatible liquid salts <100X composed of bulky asymmetric cations and anions. This class of ILs has been previously shown to significantly extend circulation time and redirect biodistribution in BALB/c mice post-IV injection via hitchhiking on red blood cell (RBC) membranes. Herein, we synthesized & screened 60 choline carboxylic acid-based ILs to coat PLGA NPs and present the impact of structurally engineering the coordinated anion identity to selectively interface and hitchhike lymphocytes, monocytes, granulocytes, platelets, and RBCs in whole mouse blood for in situ targeted drug delivery. Furthermore, we find this nanoparticle platform to be biocompatible (non-cytotoxic), translate to human whole blood by resisting serum uptake and maintaining modest hitchhiking, and also significantly extend circulation retention over 24 hours in BALB/c healthy adult mice after IV injection. Because of their altered circulation profiles, we additionally observe dramatically different organ accumulation profiles compared to bare PLGA NPs. This study establishes an initial breakthrough platform for a modular and transformative targeting technology to hitchhike onto blood components with high efficacy and safety in the bloodstream post-IV administration.

Prediction of Compound Plasma Concentration-Time Profiles in Mice Using Random Forest

Pharmacokinetic (PK) parameters such as clearance (CL) and volume of distribution (Vd) have been the subject of previous in silico predictive models. However, having information of the concentration over time profile explicitly can provide additional value like time above MIC or AUC, etc., to understand both the efficacy and safety-related aspects of a compound. In this work, we developed machine learning models for plasma concentration-time profiles after both i.v. and p.o. dosing for a series of 17 in-house projects. For explanatory variables, MACCS Keys chemical descriptors as well as in silico and experimental in vitro PK parameters were used. The predictive accuracy of random forest (RF), message passing neural network, 2-compartment models using estimated CL and Vdss, and an average model (as a control experiment) was investigated using 5-fold cross-validation (5-fold CV) and leave-one-project-out validation (LOPO-V). The predictive accuracy of RF in 5-fold CV for i.v. and p.o. plasma concentration-time profiles was the best among the models studied, with an RMSE for i.v. dosing at 0.08, 1, and 8 h of 0.245, 0.474, and 0.462, respectively, and an RMSE for p.o. dosing at 0.25, 1, and 8 h of 0.500, 0.612, and 0.509, respectively. Furthermore, by investigating the importance of the in vitro PK parameters using the Gini index, we observed that the general prior knowledge in ADME research was reflected well in the respective feature importance of in vitro parameters such as predicted human Vd (hVd) for the initial distribution, mouse intrinsic CL and unbound fraction of mouse plasma for the elimination process, and Caco2 permeability for the absorption process. Also, this model is the first model that can predict twin peaks in the concentration-time profile much better than a baseline compartment model. Because of its combination of sufficient accuracy and speed of prediction, we found the model to be fit-for-purpose for practical lead optimization.

Multi-functional chitosan copolymer modified nanocrystals as oral andrographolide delivery systems for enhanced bioavailability and anti-inflammatory efficacy

Modifying nanocrystals with functional materials have been common strategy to enlarge the enhancing ability on oral absorption via nanocrystals; however, whether the functional materials have played their full enhancing ability in oral absorption is still unknown. In this study, we synthetized a novel chitosan-based copolymer (the copolymer of sodium dodecyl sulfate (SDS), chitosan (CS) and D-α-Tocopherol polyethylene glycol 1000 succinate, SDS-CS-TPGS), and modified nanocrystals with this copolymer, aiming to enhance the oral absorption of polymer andrographolide (ADR). In real-time distribution study, we found the distribution of ADR, SDS, CS and TPGS varies in gastrointestinal tract, while the distribution of ADR and SDS-CS-TPGS was similar, revealing the SDS-CS-TPGS could able to participate in the absorption process of andrographolide timely. To explore the oral absorption enhancing ability of SDS-CS-TPGS, we prepared a series of nanocrystals modified with different materials and explored their pharmacokinetic performances on SD rats. The results showed the nanocrystals modified with SDS-CS-TPGS (S-C-TANs) exhibited the highest bioavailability, which could enhance the AUC_0-∞ of ADR from 1.291 mg/L*h to 5.275 mg/L*h (enhanced for about 4.09-folds). The enhanced anti- inflammatory efficacy was also found on ICR mice by employing ear swelling rate, TNF-α, IL-1β and IL-6 and pharmacodynamic index. These results indicated that modified with synthesized copolymer containing different functional stabilizers is an efficient strategy to enlarge the enhancing ability on oral absorption of nanocrystals.

Impact of target-mediated drug disposition on hetrombopag pharmacokinetics and pharmacodynamics in Chinese healthy subjects and patients with chronic idiopathic thrombocytopenic purpura

AIMS

The pharmacokinetics (PK) of hetrombopag were found to be nonlinear across evaluated dose ranges. The aim of this study was to develop a mechanism-based population pharmacokinetic/pharmacodynamic (PopPK/PD) model and to provide a reasonable expected therapeutic dose for a future confirmatory clinical study of hetrombopag.

METHODS

Nonlinear mixed-effects modelling was performed using pooled 2168 hetrombopag concentrations and 1526 platelet counts from 72 healthy subjects and 32 chronic idiopathic thrombocytopenic purpura (ITP) patients from two phase I studies and one phase II study. The final model was evaluated via goodness-of-fit plots, visual predictive check and nonparametric bootstrap. Simulations from the validated PopPK/PD model were used to devise an expected therapeutic dose for later confirmatory clinical study.

RESULTS

The pharmacokinetic data of hetrombopag were well described by a modified target-mediated drug disposition (TMDD) model with dual sequential first-order absorption. Mean parameter estimates (interindividual variability) were CL/F 7.66 L/h (63.5%), V_c /F 30.0 L (77.2%) and K_deg 0.693/h (87.1%). The pharmacodynamic profile was well described by a five-compartment lifespan model with four-transit and one-platelet compartments. Simulation results suggested that chronic ITP patients following 10 mg once-daily hetrombopag would able to achieve an ideal platelet count level (50-200 × 10⁹ /L).

CONCLUSION

TMDD was the primary reason leading to nonlinear PK profile of hetrombopag. Our PK/PD modelling and simulation results support 10 mg once-daily as the recommended therapeutic dose for chronic ITP patients in subsequent confirmatory clinical study of hetrombopag.

γ-Hydroxybutyric Acid-Ethanol Drug-Drug Interaction: Reversal of Toxicity with Monocarboxylate Transporter 1 Inhibitors

The drug of abuse, γ-hydroxybutyric acid (GHB), is commonly co-ingested with ethanol, resulting in a high incidence of toxicity and death. Our laboratory has previously reported that GHB is a substrate for the monocarboxylate transporters (MCTs), necessary for its absorption, renal clearance, and tissue distribution, including across the blood-brain barrier. Our goal was to investigate the drug-drug interaction (DDI) between GHB and ethanol and to evaluate MCT1 inhibition as a strategy to reverse toxicity. The toxicokinetics of this DDI were investigated, including brain-to-plasma concentration ratios, in the presence and absence of ethanol. The toxicodynamic parameters examined were respiratory depression (breathing frequency, tidal volume) and sedation (time of return-of-righting reflex). Ethanol was administered (2 g/kg i.v.) 5 minutes before the intravenous or oral administration of GHB, and MCT1 inhibitors AZD-3965 and AR-C155858 (5 mg/kg i.v.) were administered 60 minutes after GHB administration. Ethanol administration did not alter the toxicokinetics or respiratory depression caused by GHB after intravenous or oral administration; however, it significantly increased the sedation effect, measured by return-to-righting time. AZD-3965 or AR-C155858 significantly decreased the effects of the co-administration of GHB and ethanol on respiratory depression and sedation of this DDI and decreased brain concentrations and the brain-to-plasma concentration ratio of GHB. The results indicate that ethanol co-administered with GHB increases toxicity and that MCT1 inhibition is effective in reversing toxicity by inhibiting GHB brain uptake when given after GHB-ethanol administration. SIGNIFICANCE STATEMENT: These studies investigated the enhanced toxicity observed clinically when γ-hydroxybutyric acid (GHB) is co-ingested with alcohol and evaluated strategies to reverse this toxicity. The effects of the novel monocarboxylate transporter 1 (MCT1) inhibitors AR-C155858 and AZD-3965 on this drug-drug interaction have not been studied before, and these preclinical studies indicate that MCT1 inhibitors can decrease brain concentrations of GHB by inhibiting brain uptake, even when administered at times after GHB-ethanol. AZD-3965 represents a potential treatment strategy for GHB-ethanol overdoses.

Oral fate and stabilization technologies of lactoferrin: a systematic review

Lactoferrin (Lf), a bioactive protein initially found in many biological secretions including milk, is regarded as the nutritional supplement or therapeutic ligand due to its multiple functions. Research on its mode of action reveals that intact Lf or its active peptide (i.e., lactoferricin) shows an important multifunctional performance. Oral delivery is considered as the most convenient administration route for this bioactive protein. Unfortunately, Lf is sensitive to the gastrointestinal (GI) physicochemical stresses and lactoferricin is undetectable in GI digesta. This review introduces the functionality of Lf at the molecular level and its degradation behavior in GI tract is discussed in detail. Subsequently, the absorption and transport of Lf from intestine into the blood circulation, which is pivotal to its health promoting effects in various tissues, and some assisting labeling methods are discussed. Stabilization technologies aiming at preserving the structural integrity and functional properties of orally administrated Lf are summarized and compared. Altogether, this work comprehensively reviews the structure-function relationship of Lf, its oral fate and the development of stabilization technologies for the enhancement of the oral bioavailability of Lf. The existing limitations and scope for future research are also discussed.

In Vitro and In Vivo Characterization of MCT1 Inhibitor AZD3965 Confirms Preclinical Safety Compatible with Breast Cancer Treatment

Simple Summary

The vast majority of tumors originate in tissues that use different substrates and oxygen to produce energy. However, tumors are disorganized structurally and functionally, which creates areas where oxygen and nutrients are poorly available. To survive and proliferate, cancer cells adapt by switching their metabolism to lactic fermentation. Their fate is further optimized by intercellular cooperation, but this creates a weakness that can be exploited therapeutically. Indeed, AZD3965 is a new drug currently tested in clinical trials that inhibits a cooperation based on lactate swapping for glucose between fermenting and respiring cells. It inhibits lactate transporter monocarboxylate transporter 1. Here, using malignant and nonmalignant cells representative of the breast tissue and several behavioral tests in mice, we establish that AZD3965 is safe for therapeutic use against cancer. The only side effect that we detected was a short-term memory retention defect that transiently perturbed the orientation of mice in space.

Abstract

To survive and proliferate in solid tumors, cancer cells adapt and evolve rapidly in microenvironments where oxygen and substrate bioavailability fluctuates over time and space. This creates metabolic heterogeneity. Cancer cells can further cooperate metabolically, for example by swapping glycolytic end-product lactate for blood-borne glucose. This type of cooperation can be targeted therapeutically, since transmembrane lactate exchanges are facilitated by lactate-proton symporters of the monocarboxylate (MCT) family. Among new drugs, AZD3965 is a first-in-class selective MCT1 inhibitor currently tested in Phase I/II clinical trials for patients with different types of cancers. Because MCT1 can function bidirectionally, we tested here whether and how malignant and nonmalignant cells adapt their metabolism and MCT repertoire when AZD3965 inhibits either lactate import or export. Using breast-associated malignant and nonmalignant cell lines as models, we report that AZD3965 is not directly cytotoxic. In the presence of glucose and glutamine, oxidative cells can survive when lactate uptake is blocked, and proliferating cells compensate MCT1 inhibition by overexpressing MCT4, a specialized facilitator of lactate export. Phenotypic characterization of mice focusing on metabolism, muscle and brain physiology found partial and transient memory retention defect as sole consequence of MCT1 inhibition by AZD3965. We therefore conclude that AZD3965 is compatible with anticancer therapy.

Tumor-Targeted Inhibition of Monocarboxylate Transporter 1 Improves T-Cell Immunotherapy of Solid Tumors

Export of lactic acid from glycolytic cancer cells to the extracellular tumor milieu has been reported to enhance tumor growth and suppress antitumor immunity. In this study, a pH-activatable nanodrug is reported for tumor-targeted inhibition of monocarboxylate transporter-1 (MCT1) that reverses lactic acid-induced tumor immunosuppression. The nanodrug is composed of an MCT1 inhibitor (AZD3965) loaded inside the ultra-pH-sensitive nanoparticles (AZD-UPS NPs). AZD-UPS NP is produced by a microfluidics method with improved drug loading efficiency and optimal nanoparticle size over sonication methods. The nanodrug remains as intact micelles at pH 7.4 but rapidly disassembles and releases payload upon exposure to acidic pH. When combined with anti-PD-1 therapy, AZD-UPS NP leads to potent tumor growth inhibition and increases survival in two tumor models over oral administration of AZD3965 at dramatically reduced dose (>200-fold). Safety evaluations demonstrate reduced drug distribution in heart and liver tissues with decrease in toxic biomarkers such as cardiac troponin by the nanodrug. Increased T-cell infiltration and reduced exhaustive PD1⁺ Tim3⁺ T cells are found in tumors. These data illustrate that tumor-targeted inhibition of MCT1 can reverse the immune suppressive microenvironment of solid tumors for increased safety and antitumor efficacy of cancer immunotherapy.

Targeting Cancer Metabolism and Current Anti-Cancer Drugs

Several studies have exploited the metabolic hallmarks that distinguish between normal and cancer cells, aiming at identifying specific targets of anti-cancer drugs. It has become apparent that metabolic flexibility allows cancer cells to survive during high anabolic demand or the depletion of nutrients and oxygen. Cancers can reprogram their metabolism to the microenvironments by increasing aerobic glycolysis to maximize ATP production, increasing glutaminolysis and anabolic pathways to support bioenergetic and biosynthetic demand during rapid proliferation. The increased key regulatory enzymes that support the relevant pathways allow us to design small molecules which can specifically block activities of these enzymes, preventing growth and metastasis of tumors. In this review, we discuss metabolic adaptation in cancers and highlight the crucial metabolic enzymes involved, specifically those involved in aerobic glycolysis, glutaminolysis, de novo fatty acid synthesis, and bioenergetic pathways. Furthermore, we also review the success and the pitfalls of the current anti-cancer drugs which have been applied in pre-clinical and clinical studies.

Tracing Nutrient Flux Following Monocarboxylate Transporter-1 Inhibition with AZD3965

The monocarboxylate transporter 1 (MCT1) is a key element in tumor cell metabolism and inhibition of MCT1 with AZD3965 is undergoing clinical trials. We aimed to investigate nutrient fluxes associated with MCT1 inhibition by AZD3965 to identify possible biomarkers of drug action. We synthesized an 18F-labeled lactate analogue, [18F]-S-fluorolactate ([18F]-S-FL), that was used alongside [18F]fluorodeoxyglucose ([18F]FDG), and 13C-labeled glucose and lactate, to investigate the modulation of metabolism with AZD3965 in diffuse large B-cell lymphoma models in NOD/SCID mice. Comparative analysis of glucose and lactate-based probes showed a preference for glycolytic metabolism in vitro, whereas in vivo, both glucose and lactate were used as metabolic fuel. While intratumoral L-[1-13C]lactate and [18F]-S-FL were unchanged or lower at early (5 or 30 min) timepoints, these variables were higher compared to vehicle controls at 4 h following treatment with AZD3965, which indicates that inhibition of MCT1-mediated lactate import is reversed over time. Nonetheless, AZD3965 treatment impaired DLBCL tumor growth in mice. This was hypothesized to be a consequence of metabolic strain, as AZD3965 treatment showed a reduction in glycolytic intermediates and inhibition of the TCA cycle likely due to downregulated PDH activity. Glucose ([18F]FDG and D-[13C6]glucose) and lactate-based probes ([18F]-S-FL and L-[1-13C]lactate) can be successfully used as biomarkers for AZD3965 treatment.

In Vitro and In Vivo Efficacy of AZD3965 and Alpha-Cyano-4-Hydroxycinnamic Acid in the Murine 4T1 Breast Tumor Model

Monocarboxylate transporter 1 (MCT1) represents a potential therapeutic target in cancer. The objective of this study was to determine the efficacy of AZD3965 (a specific inhibitor of MCT1) and α-cyano-4-hydroxycinnamic acid (CHC, a nonspecific inhibitor of MCTs) in the murine 4T1 tumor model of triple-negative breast cancer (TNBC). Expression of MCT1 and MCT4 in 4T1 and mouse mammary epithelial cells were determined by Western blot. Inhibition of MCT1-mediated L-lactate uptake and cellular proliferation by AZD3965 and CHC was determined. Mice bearing 4T1 breast tumors were treated with AZD3965 100 mg/kg i.p. twice-daily or CHC 200 mg/kg i.p. once-daily. Tumor growth, metastasis, intra-tumor lactate concentration, immune function, tumor MCT expression, and concentration-effect relationships were determined. AZD3965 and CHC inhibited cell growth and L-lactate uptake in 4T1 cells. AZD3965 treatment resulted in trough plasma and tumor concentrations of 29.1 ± 13.9 and 1670 ± 946 nM, respectively. AZD3965 decreased the tumor proliferation biomarker Ki67 expression, increased intra-tumor lactate concentration, and decreased tumor volume, although tumor weight was not different from untreated controls. CHC had no effect on tumor volume and weight, or intra-tumor lactate concentration. AZD3965 treatment reduced the blood leukocyte count and spleen weight and increased lung metastasis, while CHC did not. These findings indicate AZD3965 is a potent MCT1 inhibitor that accumulates to high concentrations in 4T1 xenograft tumors, where it increases tumor lactate concentrations and produces beneficial effects on markers of TNBC; however, overall effects on tumor growth were minimal and lung metastases increased.