Prostacyclin analogues are effective treatments in pulmonary arterial hypertension (PAH), especially in advanced stages. Treprostinil, a stable prostacyclin analogue, can be administered as subcutaneous and intravenous infusions, oral extended-release tablets and inhalation. Inhalation offers several advantages over other routes of administration, including direct access to the lungs for localized therapy, reduced infection risk, and a painless, convenient mode of delivery. However, small lipophilic molecules like treprostinil are absorbed into the bloodstream within minutes after inhalation, resulting in a short duration of action in the lungs and systemic side effects. To address these limitations, we developed a novel strategy involving a double treprostinil prodrug tailored for pulmonary delivery. The prodrug consists of treprostinil di-esterified at its carboxylic acid with a polyethylene glycol (PEG) chain, and at its C11 hydroxyl group with butyric acid. The prodrug exhibited sustained treprostinil release in bronchoalveolar lavage fluid and serum, supporting its suitability for pulmonary delivery. It was cleaved by initial hydrolysis of the PEG chain, followed by subsequent cleavage of the short-chain fatty acid. Ex vivo studies in isolated pulmonary artery rings showed a delayed and prolonged vasorelaxation effect of the conjugate compared to the free drug. In vivo studies demonstrated significant lung retention, with detectable quantities of the compound remaining in the lungs 24 h after administration, and a markedly reduced peak serum concentration following inhalation. This double-prodrug approach represents a promising strategy for improving PAH treatment by optimizing local, sustained treprostinil delivery while minimizing systemic exposure.

Unlike traditional submerged cell cultures, nebulized drug delivery to air-liquid interface (ALI)-cultured lung cells provides a clinically relevant route for in vitro testing of inhalable drugs. Current nebulizer systems deliver non-physiologically large drug volumes. Here, we introduce the Cloud MAX technology, characterize its accuracy of dosimetry, and apply it to toxicity, efficacy, and biokinetics or permeability testing of a locked nucleic acid-modified antisense oligonucleotide (ASO). On average the Cloud MAX delivers 44% of 3–20 μL aerosolized liquid to ALI-cultured cells, the coefficient of variation (CV) of repeated drug dosing is <11%-rel. and as little as 1 μL of drug/insert (=0.25 μL/cm2) can be delivered to ALI-cultured cells. As proof of concept for dose-controlled in vitro drug testing, we demonstrated target engagement of a LIM and Calponin Homology domain 1 (LIMCH1)-specific ASO in primary lung fibroblasts from Idiopathic Pulmonary Fibrosis (IPF) patients “shielded” by an A549 alveolar epithelial layer, mimicking inhalation therapy. LIMCH1-ASO was effective in LIMCH1-silencing even at the lowest dose (0.64 nmol/cm2). Nebulization did neither impair LIMCH1-ASO efficacy nor induce cytotoxicity for the highest tested dose (3.21 nmol/cm2.) The permeability (biokinetics) of nebulized ASO through the A549 cell barrier was 14-fold faster (“burst-like”) than for larger volume (pipetted) ASO application. Computational modelling revealed that this well-known “burst-like” pharmaco−/biokinetics profile is due to small-volume drug application, not due to nebulizer-induced changes on barrier tightness (apparent permeability Papp). Thus, the Cloud MAX is a substance-efficient platform for in vitro pharmacokinetics/−dynamics testing of inhalable drugs for targeted pulmonary therapy.

Implant-associated infections caused by biofilm-forming bacteria, such as Staphylococcus aureus, remain a major clinical challenge due to their high tolerance to conventional antibiotic therapies. We report a dual-targeted therapeutic strategy that combines a tri-enzymatic cocktail designed to degrade key components of the biofilm matrix (TEC; comprising a DNA/RNA endonuclease, an endo-1,4-β-D-glucanase, and a β-N-acetylhexosaminidase), with vancomycin, both delivered via a thermosensitive poloxamer 407 hydrogel, for localized treatment of S. aureus biofilms. The formulation was evaluated both in vitro, on titanium-adherent biofilms, and in vivo, using a model of tissue cages containing titanium beads implanted in the back of guinea pigs. Animals additionally received intraperitoneal administration of vancomycin alone or combined with rifampicin. In vitro, this formulation enabled sequential drug release, with TEC delivered within the first 24 h and vancomycin for up to 96 h, and achieved >5 Log₁₀ reductions in CFU counts after two applications at 48 h interval. In vivo, biofilm-associated bacterial counts reached the detection limit (100 CFU; >5 Log10 decrease from the initial inoculum) in 75

Implant-associated infections remain a critical challenge due to the presence of biofilm-forming bacteria, which enhance tolerance to conventional treatments. This study investigates the efficacy of a tri-enzymatic cocktail (TEC; DNA/RNA endonuclease, endo-14-β-d-glucanase, β-N-acetylhexosaminidase) targeting biofilm matrix components combined with supratherapeutic doses of antibiotics encapsulated in a thermosensitive hydrogel (poloxamer P407) for local administration. In vitro, the hydrogel formulation enabled controlled release of active agents over 12 h. Vancomycin and TEC co-formulated in hydrogel achieved up to 3.8 Log10 CFU count reduction and 80 % biofilm biomass reduction on MRSA biofilms grown on titanium coupons, demonstrating enhanced efficacy as compared to individual active agents, with 1.3-3.2 log10 additional killing. Fluoroquinolone efficacy remained unchanged by enzyme addition. In vivo, in a model of tissue cages containing titanium beads implanted in the back of guinea pigs, hydrogel-delivered vancomycin maintained therapeutic levels for seven days. Coupled with an intraperitoneal administration of vancomycin for 4 days, a single local administration of hydrogel containing both vancomycin and TEC was more effective than hydrogels containing either vancomycin or TEC, achieving an additional 2.1 Log10 CFU reduction compared to local vancomycin, 2.3 Log10 compared to local TEC, and 4.3 Log10 compared to systemic vancomycin treatment alone. However, partial regrowth occurred at later stages, indicating room for further optimization. Nevertheless, these findings already underscore the potential of combining a high dose of antibiotic with an enzymatic cocktail in a sustained-release hydrogel delivery system as a promising strategy for improving the management of biofilm-associated implant infections.

Treprostinil (TRE) is a prostacyclin analogue approved for the treatment of pulmonary arterial hypertension (PAH). Despite its effectiveness, TRE has a short half-life, necessitating frequent or continuous administration to maintain therapeutic levels while minimizing adverse effects. To improve pharmacokinetics and pulmonary targeting of TRE, we designed a series of polyethylene glycol (PEG) ester conjugates for inhalation. The increase in molecular size achieved through polymer conjugation prevents the passive diffusion of TRE across the alveolar-capillary barrier, a common drawback of small, lipophilic drugs delivered to the lungs. The ester bond between TRE and PEG enables a gradual release of the active compound within the alveolar space. TRE was chemically modified with seven different alkyne-bearing linkers and subsequently conjugated to PEG-azide 6 kDa via click chemistry. These linkers were strategically designed to modulate the chemical environment around the cleavable ester bond, allowing for the systematic evaluation of the steric and electronic effects on the stability of the PEG-TRE conjugates. Drug release studies in bronchoalveolar lavage from healthy rats demonstrated that sterically hindered and electronically stabilized linkers significantly slowed the release of TRE. Moreover, conjugate stability was dependent on the enzymes availability, with a higher conjugate-enzyme ratio leading to slower release, suggesting enzyme saturation as a potential mechanism for controlled drug release. Overall, these findings demonstrate a tunable strategy for releasing drugs from polymer-drug conjugates in biological media.

Patients suffering from emphysema associated with alpha-1 antitrypsin (AAT) deficiency can benefit from augmentation therapy. AAT is administered to the patient once a week via intravenous infusion by a healthcare professional. However, only 2 % of the AAT dose reaches the lungs following intravenous infusion. Inhalation of AAT might be a convenient and effective alternative to intravenous infusion. Yet, it has shown limited therapeutic efficacy in a recent clinical trial. Here, we assessed the impact of these routes of AAT administration on AAT pharmacokinetics, lung distribution and therapeutic efficacy in mice. PEGylation of the serpin was employed to improve its therapeutic value. Intravenous injection of AAT or its local administration to the lungs resulted in a similar exposure of AAT in the lung parenchyma with however an AAT dose delivered to the lungs 45 times lower than the injected dose. Conjugation of AAT to a 2-armed 40 kDa polyethylene glycol (PEG) chain prolonged its half-life in plasma and lungs by 1.6-times, decreased its penetration in the lung tissue by both routes of administration but did not markedly affect the lung exposure to AAT. The PEG moiety in PEG-AAT was cleared more slowly than the protein moiety and high PEG quantities remained in the lung tissue and alveolar macrophages several days after intratracheal instillation. Pulmonary administration and PEGylation both improved AAT efficacy to prevent lung injury and inflammation in a murine model of chronic obstructive pulmonary disease where lung inflammation was induced by delivering porcine pancreatic elastase and lipopolysaccharide locally to the airways. Anti-AAT and anti-PEG antibodies were generated by AAT and PEG-AAT administration, as expected for a foreign protein. However, anti-PEG antibodies did not significantly contribute to the overall anti-drug antibody titers against the conjugate. AAT and PEG-AAT showed good stability to jet nebulization. This study provides new insights into the impact of administration route and PEGylation on lung exposure, clearance, therapeutic efficacy, and safety of AAT. It highlights that inhalation of AAT might effectively replace its intravenous infusion in augmentation therapy.

BackgroundBiofilm-associated pulmonary infections pose therapeutic challenges in cystic fibrosis patients, especially when involving multiple bacterial species. Enzymatic degradation of the biofilm matrix may offer a potential solution to enhance antibiotic efficacy. This study investigated the repurposing of DNase I, commonly used for its mucolytic activity in cystic fibrosis, to target extracellular DNA within biofilms, as well as potential synergies with alginate lyase and broad-spectrum antibiotics in dual-species biofilms of Pseudomonas aeruginosa and Staphylococcus aureus.MethodsDual-species biofilms were grown in artificial sputum medium using S. aureus and P. aeruginosa isolated by pairs from the same patients and exposed to various combinations of enzymes, meropenem, or tobramycin. Activity was assessed by measuring biofilm biomass and viable counts. Matrix degradation and decrease in bacterial load were visualized using confocal microscopy. Biofilm viscoelasticity was estimated by rheology.ResultsNearly complete destruction of the biofilms was achieved only if combining the enzymatic cocktail with the two antibiotics, and if using supratherapeutic levels of DNase I and high concentrations of alginate lyase. Biofilms containing non-pigmented mucoid P. aeruginosa required higher antibiotic concentrations, despite low viscoelasticity. In contrast, for biofilms with pigmented mucoid P. aeruginosa, a correlation was observed between the efficacy of different treatments and the reduction they caused in elasticity and viscosity of the biofilm.ConclusionsIn this complex, highly drug-tolerant biofilm model, enzymes prove useful adjuvants to enhance antibiotic activity. However, the necessity for high enzyme concentrations emphasizes the need for thorough concentration-response evaluations and safety assessments before considering clinical applications.

Spray drying is a widely employed method for generating dry powder formulations for inhalation. Yet, it presents substantial challenges when applied to therapeutic proteins due to stability issues. The formation of protein aggregates during the atomization and the heating steps can diminish protein activity and raise immunogenicity concerns. Here, we assessed the impact of varying levels of protein aggregates generated during spray-drying on the fate and the immunogenicity of the human monoclonal antibody NIP228 following intratracheal administration in mice. Aggregate-free rhodamine labelled NIP228 was spray-dried with or without 1% polysorbate 80 surfactant, resulting in the generation of powder formulations with associated low and high protein aggregate levels, respectively. Confocal imaging highlighted the presence of aggregates in the lungs for both powders but not for the solution following a single dose administration. Flow cytometry analysis designated alveolar macrophages as the main immune cells taking up rhod-NIP228 in the lungs with very little involvement of dendritic cells and interstitial macrophages. Notably, repeated intratracheal administration of the three formulations in mice did not impact the magnitude of the anti-drug antibody response in sera or broncho-alveolar lavages. Furthermore, the pulmonary route appeared to evoke a more robust immune response when compared to subcutaneous administration. Overall, the level of NIP228 aggregation in this study did not appear to be the primary driver of NIP228 immunogenicity following delivery to the lungs in mice.These findings shed new light on the interplay between protein aggregation and immunogenicity in the context of the pulmonary delivery of therapeutic proteins.

Human neutrophil elastase (hNE), a serine protease released by neutrophils during inflammation, plays a major role in the pathophysiology of several conditions especially in inflammatory lung diseases. Its inhibition constitutes, therefore, a promising therapeutic strategy to combat these diseases. In this work, we characterized the in vitro properties of a VHH (i.e., the antigen binding domain of camelid heavy chain-only antibodies), referred to as NbE201. This VHH is able to inhibit tightly, selectively and competitively both human and murine elastases with the inhibition constants ( K i ) of 4.1 ± 0.9 nM and 36.8 ± 3.9 nM, respectively. The IC 50 for the inhibition of the hydrolysis of elastin is in the same range to that of alpha-1 antitrypsin (i.e., the main endogenous inhibitor of hNE also used in the clinic) and 14 times better than that of Sivelestat (i.e., the 2nd clinically approved hNE inhibitor). The X-ray crystal structure of the NbE201-hNE complex reveals that the Complementarity Determining Regions CDR1 and CDR3 of the VHH bind into the substrate binding pocket of hNE and prevent the access to small or macromolecular substrates. They do not, however, bind deep enough into the pocket to be hydrolyzed. NbE201 is highly stable towards oxidation, deamidation, and chemical or thermal denaturation. NbE201 is therefore likely to tolerate manufacturing processes during drug development. These results highlight the high potential of NbE201 as a (pre)clinical tool to diagnose and treat diseases associated with excessive hNE activity, and for fundamental research to better understand the role of hNE in these conditions.

Recombinant human deoxyribonuclease I (rhDNase, Pulmozyme®) is the most frequently used mucolytic agent for the symptomatic treatment of cystic fibrosis (CF) lung disease. Conjugation of rhDNase to polyethylene glycol (PEG) has been shown to greatly prolong its residence time in the lungs and improve its therapeutic efficacy in mice. To present an added value over current rhDNase treatment, PEGylated rhDNase needs to be efficiently and less frequently administrated by aerosolization and possibly at higher concentrations than existing rhDNase. In this study, the effects of PEGylation on the thermodynamic stability of rhDNase was investigated, using linear 20 kDa, linear 30 kDa and 2-armed 40 kDa PEGs. The suitability of PEG30-rhDNase to electrohydrodynamic atomization (electrospraying) as well as the feasibility of using two vibrating mesh nebulizers, the optimized eFlow® Technology nebulizer (eFlow) and Innospire Go, at varying protein concentrations were investigated. PEGylation was shown to destabilize rhDNase upon chemical-induced denaturation and ethanol exposure. Yet, PEG30-rhDNase was stable enough to withstand aerosolization stresses using the eFlow and Innospire Go nebulizers even at higher concentrations (5 mg of protein per ml) than conventional rhDNase formulation (1 mg/ml). High aerosol output (up to 1.5 ml per min) and excellent aerosol characteristics (up to 83% fine particle fraction) were achieved while preserving protein integrity and enzymatic activity. This work demonstrates the technical feasibility of PEG-rhDNase nebulization with advanced vibrating membrane nebulizers, encouraging further pharmaceutical and clinical developments of a long-acting PEGylated alternative to rhDNase for treating patients with CF.

"Lipoid Pneumonia Associated with Polyethylene Glycol Chronic Aspiration." American Journal of Respiratory and Critical Care Medicine, 207(8), pp. e71–e72

Alpha-1 antitrypsin (AAT) is an endogenous inhibitor of serine proteases which, in physiological conditions, neutralizes the excess of neutrophil elastase and other serine proteases in tissues and especially the lungs. Weekly intravenous infusion of plasma-purified human AAT is used to treat AAT deficiency-associated lung disease. However, only 2 % of the AAT dose reach the lungs after intravenous infusion. Inhalation of AAT might offer an alternative route of administration. Yet, the rapid clearance of AAT from the respiratory tract results in high and frequent dosing by inhalation and limited efficacy. In the present study, we produced and characterized in vitro a PEGylated version of AAT which could offer a prolonged body residence time and thereby be useful for augmentation therapy by the intravenous and inhalation routes. Two PEGylation reactions - N-terminal and thiol PEGylation - and three polyethylene glycol (PEG) chains - linear 30 kDa, linear 40 kDa and 2-armed 40 kDa - were used. The yields of mono-PEGylated AAT following purification by anion exchange chromatography were 40-50 % for N-terminal PEGylation and 60-70% for thiol PEGylation. The PEG-AAT conjugates preserved the ability to form a protease-inhibitor complex with neutrophil elastase and proteinase 3 as well as the full inhibitory capacity to neutralize neutrophil elastase activity. These results open up interesting prospects for PEGylated AAT to achieve a prolonged half-life and an improved therapeutic efficacy in vivo.

Conjugation to polyethylene glycol (PEG) is a widely used approach to improve the therapeutic value of proteins essentially by prolonging their body residence time. PEGylation may however induce changes in the structure and/or the stability of proteins and thus on their function(s). The effects of PEGylation on the thermodynamic stability can either be positive (stabilization), negative (destabilization), or neutral (no effect). Moreover, various factors such as the PEG length and PEGylation site can influence the consequences of PEGylation on the structure and stability of proteins. In this study, the effects of PEGylation on the structure, stability, and polymerization of alpha1-antitrypsin (AAT) were investigated, using PEGs with different lengths, different structures (linear or 2-armed) and different linking chemistries (via amine or thiol) at two distinct positions of the sequence. The results show that whatever the size, position, and structure of PEG chains, PEGylation (a) does not induce significant changes in AAT structure (either at the secondary or tertiary level); (b) does not alter the stability of the native protein upon both chemical- and heat-induced denaturation; and (c) does not prevent AAT to fully refold and recover its activity following chemical denaturation. However, the propensity of AAT to aggregate upon heat treatment was significantly decreased by PEGylation, although PEGylation did not prevent the irreversible inactivation of the enzyme. Moreover, conjugation to PEG, especially 2-armed 40 kDa PEG, greatly improved the proteolytic resistance of AAT. PEGylation of AAT could be a promising strategy to prolong its half-life after infusion in AAT-deficient patients and thereby decrease the frequency of infusions.

Objectives Two CFTR-dependent β-adrenergic sweat rate tests applying intradermal drug injections were reported to better define diagnosis and efficacy of CFTR-directed therapies. The aim of this work was to develop and test a needle-free image-based test and to provide an accurate analysis of the responses. Methods The modified method was conducted by applying two successive iontophoresis sessions using the Macroduct device. Efficiency of drug delivery was tested by evaporimetry. Cholinergically stimulated sweating was evoked by pilocarpine iontophoresis. β-adrenergically stimulated sweating was obtained by iontophoresis of isoproterenol and aminophylline in the presence of atropine and ascorbic acid. A nonlinear mixed-effects (NLME) approach was applied to model volumes of sweat and subject-specific effects displaying inter- and intra-subject variability. Results Iontophoresis provided successful transdermal delivery of all drugs, including almost neutral isoproterenol and aminophylline. Pilocarpine was used at a concentration ∼130-times lower than that used in the classical Gibson and Cooke sweat test. Addition of ascorbic acid lowered the pH of the solution, made it stable, prevented isoproterenol degradation and promoted drug iontophoresis. Maximal secretory capacity and kinetic rate of β-adrenergic responses were blunted in CF. A cutoff of 5.2 minutes for ET50, the time to reach the half maximal secretion, discriminated CF from controls with a 100% sensitivity and specificity. Heterozygous showed an apparently reduced kinetic rate and a preserved secretory capacity. Conclusion We tested a safe, well-tolerated needle-free image-based sweat test potentially applicable in children. Modelling responses by NLME allowed evaluating metrics of CFTR-dependent effects reflecting secretory capacity and kinetic rate.

Protein therapeutics have gained momentum in recent years and become a pillar in treating many diseases and the only choice in several ailments. Protein therapeutics are highly specific, tunable, and less toxic than conventional small drug molecules. However, reaping the full benefits of therapeutic proteins in the clinics is often hindered by issues of immunogenicity and short half-life due essentially to fast renal clearance and enzymatic degradation. Advances in polymer chemistry and protein engineering allowed overcoming some of these limitations. Strategies to prolong the half-life of proteins rely on increasing their size and stability and/or fusing them to endogenous proteins (albumin, Fc fragment of antibody) to hijack physiological pathways involved in protein recycling. On the downside, these modifications might alter therapeutic proteins structure and function. Therefore, a compromise between half-life and activity is sought. This review covers half-life extension strategies using natural and synthetic polymers as well as fusion to other proteins and sheds light on genetic engineering strategies and chemical and enzymatic reactions to achieve this goal. Promising strategies and successful applications in the clinics are highlighted.

Inhalation of recombinant human deoxyribonuclease I (rhDNase) is a gold‐standard therapy in the management of cystic fibrosis (CF). Yet, the rapid elimination of the mucolytic from the lungs requires its daily administration and rhDNase contributes to the high therapy burden of patients. Here, a long‐acting version of rhDNase that is delivered once weekly instead of once daily is presented. Conjugation of rhDNase to a polyethylene glycol (PEG) chain sustains its presence and mucolytic activity within murine lungs for more than 15 days. One single dose of PEGylated rhDNase is as effective as 1 daily dose of unconjugated rhDNase during five days to decrease the DNA content in the lungs of β‐ENaC mice, a model of the CF lung disease. Moreover, once weekly administration of PEGylated rhDNase over four weeks decreases both the DNA content and the neutrophil counts in the lungs of β‐ENaC mice. PEGylated rhDNase is stable to jet nebulization. Finally, multiple high‐dose administrations of PEGylated rhDNase for up to 3 months do not cause any significant pulmonary or systemic toxicity, nor accumulation of the rhDNase or PEG moieties in biological fluids. PEGylation of rhDNase may offer a convenient long‐acting mucolytic to patients with CF.