Inherited retinal degenerative diseases (IRDs), including retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA), cause progressive vision impairment due to photoreceptor degeneration. We previously demonstrated the protective effects of reserpine in models of CEP290-LCA and in the female Rhodopsin-P23H rat model of autosomal dominant RP. Given that reserpine is limited by side effects, we expanded our compound screen using retinal organoids from the rd16 mouse model of CEP290-LCA to include structurally diverse small molecules that may converge on proteostasis pathways. Follow-up evaluations in Rhodopsin-P23H rats, human CEP290-LCA retinal organoids, and rd10 mice (a model of PDE6B-RP) identified halofantrine as the most promising molecule, conferring strong protection to both rod and cone photoreceptors and demonstrating therapeutic potential across the divergent IRD models tested. Transcriptome analysis revealed a convergent molecular response to halofantrine across these models, primarily through upregulation of oxidative phosphorylation and ribosomal processes. Notably, halofantrine elicited significant improvements in retinal function, as assessed by electroretinography, despite pharmacokinetically limited and transient retinal exposure after subconjunctival injection in Rhodopsin-P23H rats. Our studies highlight the potential of halofantrine as a gene-independent therapy and suggest that it may be developed for ocular delivery via eye drops for the treatment of IRDs.

Rabies remains a preventable yet fatal disease that continues to claim lives in low- and middle-income countries due to barriers in accessing post-exposure prophylaxis (PEP). With Gavi, the Vaccine Alliance, now supporting PEP provision in rabies-endemic countries, understanding access barriers is critical. We used mixed-methods to synthesise quantitative data on bite patients (>10,000) captured through an Integrated Bite Case Management platform across four regions of Tanzania, with qualitative data from hotline calls and peer-support chat established among health and veterinary workers from 2018 to 2024. We applied an expanded healthcare access framework comprising six dimensions: availability, accessibility, affordability, accommodation, acceptability, and appropriateness to guide our analyses and assess barriers and facilitators to PEP delivery and uptake in these regions. We identified interconnected barriers to PEP access including recurrent vaccine stockouts (up to 9.2% regionally); long travel distances that were greater for rural patients (on average: 34 vs 13 km for urban patients) who represented the majority at risk; and unaffordable direct and indirect costs leading bite victims to either not start or abandon PEP, incur risky delays or default to traditional remedies. Incorrect bite patient management, including misuse of biologicals sold at unregulated private pharmacies led to preventable deaths, while insufficient vaccination supplies and inadequate service hours, increased risks and costs to patients. Despite these gaps, peer-support mechanisms improved patient management and real-time problem-solving. PEP delivery in Tanzania is undermined by systemic barriers across all access dimensions. Addressing these requires decentralizing vaccine delivery to prioritized accessible facilities, ensuring reliable stock and supplies for intradermal administration, reducing patient costs, strengthening health worker capacity through training and support, and regulating private providers. Lessons from Tanzania highlight the need for context-sensitive, equity-focused strategies to maximize the impact of Gavi's investment and accelerate progress toward Zero by 30.

Highly lipophilic (logP > 5) pharmaceutical candidates face oral bioavailability challenges that may be minimized by targeting drug delivery to chylomicrons (CMs), chaperones into lymphatic circulation, potentially reducing first-pass metabolic events. Extant models for CM assembly (i.e., Caco-2) by which lymphatic transport may be interrogated in vitro insufficiently recapitulate the specialized lipoprotein synthesis pathways of the small intestine. Here, we leveraged a pulse-chase approach to investigate the response of differentiated primary human duodenum (hDuo) and murine ileum (mIle) enteroid monolayers to mixed micelle treatment with oleic acid (OA) and 2-monoolein (2-MO) lipid digestion products. Monolayers were assessed for changes in (Ia) lipoprotein secretion, (Ib) re-esterification enzyme expression, and (II) CM transport of the model lipophilic compounds halofantrine (HF; logP 7.34) and navitoclax (NX; logP 7.93). Primary cells were found to favor basal-polarized apolipoprotein B-48 (apoB-48) release that was distinct from the bidirectional apoB-100 output of Caco-2. Primary monolayers stimulated by 2-MO secreted ρ < 1.006 g/mL lipoproteins with more TG mass (∼3.5-fold) and greater diameter (>40-fold) than cells receiving OA alone. While the cell line expressed more mttp at baseline, lipid coincubation upregulated mgat2 transcription in hDuo and mIle only, indicating preserved 2-MG re-esterification activity. Drug appearance in secreted lipoproteins was higher in stimulated mIle than Caco-2 (4.6- vs 1.6-fold for HF; 14.9- vs 1.3-fold for NX), with the primary culture model transporting a larger proportion of the dose via CMs than the cell line standard. We concluded that pulse-chase in primary monolayer cultures is a promising New Approach Methodology (NAM) for measuring intestinal lymphatic transport of lipid-formulated drugs and could offer, with refinement and validation, an alternative to the lymph-cannulated animal model.

Background/Objectives: Despite the recognized importance and distinctive characteristics of the intestinal lymphatic pathway in drug absorption, its pharmacokinetic modeling remains largely unexplored. This study aimed to address this gap by developing a physiologically based pharmacokinetic model (PBPK) to represent the oral lymphatic uptake of halofantrine following a fatty meal. Methods: Using GastroPlus™ 9.8.3 and published literature data, halofantrine absorption, distribution, metabolism, and elimination in both fasting and fed states were modeled. As the used software does not directly simulate intestinal lymphatic transport, lymphatic involvement in the fed state was examined indirectly through parameter adjustments such as first-pass metabolism, pKa-driven solubility changes, and bile-salt-mediated solubilization, with the aid of molecular dynamics simulations under post-prandial pH. Results: The pharmacokinetic models revealed a reduction in the first-pass effect of halofantrine in the fed state compared to that in the fasting state. While adjustments in metabolism kinetics sufficed for constructing a representative PBPK model in the fasting state, capturing the fed-state profile required both modifications to metabolism kinetics and other parameters related to the structural rearrangements of halofantrine driven by the changes in intestinal pH following food intake. These changes were confirmed using molecular dynamics simulations of halofantrine in pHs reflecting the post-prandial conditions. Conclusions: This study underscores the need for further exploration and direct modeling of intestinal lymphatic uptake via PBPK models, highlighting its underexplored status in simulation algorithms. Moreover, the importance of integrating representative physicochemical factors for drugs, particularly in post-prandial conditions or lipid formulations, is evident. Overall, these findings contribute to advancing predictive regulatory and developmental considerations in drug development using post hoc analyses.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a pressing global threat, having emerged in December 2019. Alongside it, Middle East respiratory syndrome coronavirus (MERS-CoV), a highly pathogenic human coronavirus, was identified in 2012 and continues to cause seasonal outbreaks in the Middle East. The persistence of these deadly human coronaviruses underscores the need for ongoing research on broad-spectrum antivirals. Human alveolar A549 cells have been widely used to study respiratory virus infections; however, there is a lack of standardized cell models that are permissive to these diverse lethal coronaviruses. To facilitate the assessment and validation of antiviral treatments, a robust human cell model that is susceptible to SARS-CoV-2, MERS-CoV, and other human coronavirus family members is indispensable. SARS-CoV-2 uses the angiotensin converting enzyme 2 (Ace2) receptor for entry and transmembrane serine protease 2 (Tmprss2) to prime its spike protein, while MERS-CoV relies on the dipeptidyl peptidase 4 receptor (Dpp4) for cellular entry, both of which are minimally expressed in A549 cells. In this study, we fine-tuned the expression levels of each receptor for optimal viral entry and infectivity using lentiviral transduction, cell sorting and clone selection. We successfully developed a robust human cell model expressing multiple viral receptors and demonstrated its susceptibility to both lethal coronaviruses and seasonal human coronaviruses, OC43 and 229E. We also compared two known 3C-like protease inhibitors and found that Nirmatrelvir is superior to Pomotrelvir in terms of pan-coronavirus antiviral activity. Furthermore, we tested 13 known antimalarial drugs and identified Halofantrine as having antiviral activity against SARS-CoV-2. Our findings suggest that this novel human cell model is a valuable and versatile tool for the screening and identification of pan-CoV antiviral drugs.

Intestinal lymphatic absorption is a crucial alternative to portal uptake for highly lipophilic drugs (log P > 5), bypassing first-pass metabolism. Unlike the portal-hepatic pathway, lymphatic uptake is rarely considered in physiologically based pharmacokinetic (PBPK) models for oral delivery. Our study developed an innovative Gastro-Intestinal (GI)-lymph-PBPK model that includes GI absorption, chylomicron extraction (CE) to rescue drugs from gut extraction (GE), and bypass hepatic extraction (HE). This model introduces CE clearance (CLCE), competing with GE clearance, to estimate the drug proportion subjected to CE versus GE. PBPK analysis for Buprenorphine revealed extensive GE (0.87) and HE (0.58), explaining the low bioavailability (F%) of 5.28% in rats. Buprenorphine prodrugs activated CLCE, leading to CE ranging from 0.37 to 0.79, boosting oral F% to 39.9%-79.9% in rats. To translate from rat to human, our model considered species differences in GI transit time, formulation, food-dependent drug dissolution, allometric scaling in CLCE, and between species variability in gut metabolism. Using Halofantrine, we established an allometric scaling factor for CLCE at 1.1. Accounting for six times faster human gut metabolism, our model predicted an extremely low oral F% of 0.382% for Buprenorphine in humans. Incorporating the allometric scaled CLCE competing with the extensive gut metabolism, our model predicted Buprenorphine prodrugs remains effective in enabling substantial absorption boosts, with oral F% estimates ranging from 15.8% to 56.7% in humans. This study highlights the significant potential of GI-lymph-PBPK modeling in predicting intestinal lymphatic absorption and facilitating cross-species translation.

Because no information is available on the use of halofantrine during breastfeeding, an alternate drug may be preferred, especially while nursing a newborn or preterm infant.[1]

The development of novel antiplasmodial compounds with broad-spectrum activity against different stages of Plasmodium parasites is crucial to prevent malaria disease and parasite transmission. This study evaluated the antiplasmodial activity of seven novel hydrazone compounds (referred to as CB compounds: CB-27, CB-41, CB-50, CB-53, CB-58, CB-59, and CB-61) against multiple stages of Plasmodium parasites. All CB compounds inhibited blood stage proliferation of drug-resistant or sensitive strains of Plasmodium falciparum in the low micromolar to nanomolar range. Interestingly, CB-41 exhibited prophylactic activity against hypnozoites and liver schizonts in Plasmodium cynomolgi, a primate model for Plasmodium vivax. Four CB compounds (CB-27, CB-41, CB-53, and CB-61) inhibited P. falciparum oocyst formation in mosquitoes, and five CB compounds (CB-27, CB-41, CB-53, CB-58, and CB-61) hindered the in vitro development of Plasmodium berghei ookinetes. The CB compounds did not inhibit the activation of P. berghei female and male gametocytes in vitro. Isobologram assays demonstrated synergistic interactions between CB-61 and the FDA-approved antimalarial drugs, clindamycin and halofantrine. Testing of six CB compounds showed no inhibition of Plasmodium glutathione S-transferase as a putative target and no cytotoxicity in HepG2 liver cells. CB compounds are promising candidates for further development as antimalarial drugs against multidrug-resistant parasites, which could also prevent malaria transmission.

In recent years, the drainage of fluids, immune cells, antigens, fluorescent tracers, and other solutes from the brain has been demonstrated to occur along lymphatic outflow pathways to the deep cervical lymph nodes in the neck. To the best of our knowledge, no studies have evaluated the lymphatic transport of therapeutics from the brain. The objective of this study was to determine the lymphatic transport of model therapeutics of different molecular weights and lipophilicity from the brain using cervical lymph cannulation and ligation models in rats. To do this, anesthetized Sprague-Dawley rats were cannulated at the carotid artery and cannulated, ligated, or left intact at the cervical lymph duct. Rats were administered [14]C-ibuprofen (206.29 g/mol, logP 3.84), [3]H-halofantrine HCl (536.89 g/mol, logP 8.06), or [3]H-albumin (∼65,000 g/mol) via direct injection into the brain striatum at a rate of 0.5 μL/min over 16 min. Plasma or cervical lymph samples were collected for up to 6-8 h following dosing, and brain and lymph nodes were collected at 6 or 8 h. Samples were subsequently analyzed for radioactivity levels via scintillation counting. For [14]C-ibuprofen, plasma concentrations over time (plasma AUC0-6h) were >2 fold higher in lymph-ligated rats than in lymph-intact rats, suggesting that ibuprofen is cleared from the brain primarily via nonlymphatic routes (e.g., across the blood-brain barrier) but that this clearance is influenced by changes in lymphatic flow. For [3]H-halofantrine, >73% of the dose was retained at the brain dosing site in lymph-intact and lymph-ligated groups, and plasma AUC0-8h values were low in both groups (<0.3% dose.h/mL), consistent with the high retention in the brain. It was therefore not possible to determine whether halofantrine undergoes lymphatic transport from the brain within the duration of the study. For [3]H-albumin, plasma AUC0-8h values were not significantly different between lymph-intact, lymph-ligated, and lymph-cannulated rats. However, >4% of the dose was recovered in cervical lymph over 8 h. Lymph/plasma concentration ratios of [3]H-albumin were also very high (up to 53:1). Together, these results indicate that [3]H-albumin is transported from the brain not only via lymphatic routes but also via the blood. Similar to other tissues, the lymphatics may thus play a significant role in the transport of macromolecules, including therapeutic proteins, from the brain but are unlikely to be a major transport pathway from the brain for small molecule drugs that are not lipophilic. Our rat cervical lymph cannulation model can be used to quantify the lymphatic drainage of different molecules and factors from the brain.

Candida albicans, a prominent opportunistic pathogenic fungus in the human population, possesses the capacity to induce life-threatening invasive candidiasis in individuals with compromised immune systems despite the existence of antifungal medications. When faced with macrophages or neutrophils, C. albicans demonstrates its capability to endure oxidative stress through the utilization of antioxidant enzymes. Therefore, the enhancement of oxidative stress in innate immune cells against C. albicans presents a promising therapeutic approach for the treatment of invasive candidiasis. In this study, we conducted a comprehensive analysis of a library of drugs approved by the Food and Drug Administration (FDA). We discovered that halofantrine hydrochloride (HAL) can augment the antifungal properties of oxidative damage agents (plumbagin, menadione, and H2O2) by suppressing the response of C. albicans to reactive oxygen species (ROS). Furthermore, our investigation revealed that the inhibitory mechanism of HAL on the oxidative response is dependent on Cap1. In addition, the antifungal activity of HAL has been observed in the Galleria mellonella infection model. These findings provide evidence that targeting the oxidative stress response of C. albicans and augmenting the fungicidal capacity of oxidative damage agents hold promise as effective antifungal strategies.

The lymphatic system plays a crucial role in the absorption of lipophilic drugs, making it an important route for drug delivery. In this study, an in vitro model using Intralipid[®] was developed to investigate the lymphatic uptake of drugs. The model was validated using cannabidiol, halofantrine, quercetin, and rifampicin. Remarkably, the uptake of these drugs closely mirrored what would transpire in vivo. Furthermore, adding peanut oil to the model system significantly increased the lymphatic uptake of rifampicin, consistent with meals containing fat stimulating lymphatic drug uptake. Conversely, the inclusion of pluronic L-81 was observed to inhibit the lymphatic uptake of rifampicin in the model. This in vitro model emerges as a valuable tool for investigating and predicting drug uptake via the lymphatic system. It marks the first phase in developing a physiologically based predictive tool that can be refined further to enhance the precision of drug interaction predictions with chylomicrons and their subsequent transport via the lymphatic system. Moreover, it can be employed to explore innovative drug formulations and excipients that either enhance or hinder lymphatic drug uptake. The insights gained from this study have significant implications for advancing drug delivery through the lymphatic system.