Systemic Exposure, Metabolism, and Elimination of [14C]-Labeled Amino Lipid, Lipid 5, after a Single Administration of mRNA Encapsulating Lipid Nanoparticles to Sprague-Dawley Rats.

The emerging therapeutic modality of lipid nanoparticle (LNP)-encapsulated mRNAs has demonstrated promising clinical results when used as vaccines and is currently being tested in formulations for a wide range of targeted chronic disease treatments. These therapeutics are multicomponent assemblages of well-characterized naturally occurring molecules in addition to xenobiotic molecules, whose in vivo distributions are poorly understood. Here, the metabolic outcome and in vivo elimination of heptadecan-9-yl 8-((2-hydroxyethyl) (8-(nonyloxy)-8-oxooctyl)amino)octanoate (Lipid 5), a key xenobiotic amino lipid in LNP formulations, were assessed after intravenous administration of 14C-labeled Lipid 5 to Sprague-Dawley rats. Intact Lipid 5 was predominantly cleared from plasma within 10 hour after dosing, with only small quantities (<1% of 14C dose) of a single diacid metabolite detected after 10 hour. Lipid 5 was rapidly metabolized via ester hydrolysis into aliphatic alcohols and diacidic amino head group moieties, which were further metabolized via ß-oxidation. Overall, >90% of the administered Lipid 5-derived 14C was recovered in urine (65%) and feces (35%), predominantly as oxidative metabolites, within 72 hour after dosing, indicating rapid renal and hepatic elimination. In vitro metabolite identification after incubation with human, nonhuman primate, and rat hepatocytes showed similar metabolites to those found in vivo. No meaningful differences were observed in Lipid 5 metabolism or elimination by sex. In conclusion, Lipid 5, a critical amino lipid component of LNPs for mRNA therapeutic delivery, showed minimal exposure, rapid metabolism, and near-complete elimination of 14C metabolites in rats. SIGNIFICANCE STATEMENT: Heptadecan-9-yl 8-((2-hydroxyethyl) (8-(nonyloxy)-8-oxooctyl)amino)octanoate (Lipid 5) is a key component of lipid nanoparticles used for the delivery of mRNA-based medicines; understanding the rates and routes of its clearance is crucial to assessing its long-term safety in lipid nanoparticle technology. This study conclusively established the rapid metabolism, and near-complete elimination of intravenously administered [14C]Lipid 5 in rats via both liver and kidney as oxidative metabolites derived from ester hydrolysis and subsequent ß-oxidation.

Biodistribution of Lipid 5, mRNA, and Its Translated Protein Following Intravenous Administration of mRNA-Encapsulated Lipid Nanoparticles in Rats.

RNA-based therapeutics and vaccines represent a novel and expanding class of medicines, the success of which depends on the encapsulation and protection of mRNA molecules in lipid nanoparticle (LNP)-based carriers. With the development of mRNA-LNP modalities, which can incorporate xenobiotic constituents, extensive biodistribution analyses are necessary to better understand the factors that influence their in vivo exposure profiles. This study investigated the biodistribution of heptadecan-9-yl 8-((2-hydroxyethyl)(8-(nonyloxy)-8-oxooctyl)amino)octanoate (Lipid 5)-a xenobiotic amino lipid-and its metabolites in male and female pigmented (Long-Evans) and nonpigmented (Sprague Dawley) rats by using quantitative whole-body autoradiography (QWBA) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques. After intravenous injection of Lipid 5-containing LNPs, 14C-containing Lipid 5 ([14C]Lipid 5) and radiolabeled metabolites ([14C]metabolites) were rapidly distributed, with peak concentrations reached within 1 hour in most tissues. After 10 hours, [14C]Lipid 5 and [14C]metabolites concentrated primarily in the urinary and digestive tracts. By 24 hours, [14C]Lipid 5 and [14C]metabolites were localized almost exclusively in the liver and intestines, with few or no concentrations detected in non-excretory systems, which is suggestive of hepatobiliary and renal clearance. [14C]Lipid 5 and [14C]metabolites were completely cleared within 168 hours (7 days). Biodistribution profiles were similar between QWBA and LC-MS/MS techniques, pigmented and nonpigmented rats, and male and female rats, excluding the reproductive organs. In conclusion, the rapid clearance through known excretory systems, with no evidence of redistribution for Lipid 5 or accumulation of [14C]metabolites, provides confidence for the safe and effective use of Lipid 5-containing LNPs. SIGNIFICANCE STATEMENT: This study demonstrates the rapid, systemic distribution of intact and radiolabeled metabolites of Lipid 5, a xenobiotic amino lipid component of novel mRNA-LNP medicines, and its effective clearance without substantial redistribution after intravenous administration; additionally, findings were consistent between different mRNAs encapsulated within LNPs of similar composition. This study confirms the applicability of current analytical methods for lipid biodistribution analyses, and taken together with appropriate safety studies, supports the continued use of Lipid 5 in mRNA-medicines.

The Storage and In-Use Stability of mRNA Vaccines and Therapeutics: Not A Cold Case.

The remarkable impact of mRNA vaccines on mitigating disease and improving public health has been amply demonstrated during the COVID-19 pandemic. Many new mRNA-based vaccine and therapeutic candidates are in development, yet the current reality of their stability limitations requires their frozen storage. Numerous challenges remain to improve formulated mRNA stability and enable refrigerator storage, and this review provides an update on developments to tackle this multi-faceted stability challenge. We describe the chemistry underlying mRNA degradation during storage and highlight how lipid nanoparticle (LNP) formulations are a double-edged sword: while LNPs protect mRNA against enzymatic degradation, interactions with and between LNP excipients introduce additional risks for mRNA degradation. We also discuss strategies to improve mRNA stability both as a drug substance (DS) and a drug product (DP) including the (1) design of the mRNA molecule (nucleotide selection, primary and secondary structures), (2) physical state of the mRNA-LNP complexes, (3) formulation composition and purity of the components, and (4) DS and DP manufacturing processes. Finally, we summarize analytical control strategies to monitor and assure the stability of mRNA-based candidates, and advocate for an integrated analytical and formulation development approach to further improve their storage, transport, and in-use stability profiles.

Impact of lipid nanoparticle size on mRNA vaccine immunogenicity.

Lipid nanoparticles (LNP) are effective delivery vehicles for messenger RNA (mRNA) and have shown promise for vaccine applications. Yet there are no published reports detailing how LNP biophysical properties can impact vaccine performance. In our hands, a retrospective analysis of mRNA LNP vaccine in vivo studies revealed a relationship between LNP particle size and immunogenicity in mice using LNPs of various compositions. To further investigate this, we designed a series of studies to systematically change LNP particle size without altering lipid composition and evaluated biophysical properties and immunogenicity of the resulting LNPs. While small diameter LNPs were substantially less immunogenic in mice, all particle sizes tested yielded a robust immune response in non-human primates (NHP).

Author Correction: Naturally-occurring cholesterol analogues in lipid nanoparticles induce polymorphic shape and enhance intracellular delivery of mRNA.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Naturally-occurring cholesterol analogues in lipid nanoparticles induce polymorphic shape and enhance intracellular delivery of mRNA.

Endosomal sequestration of lipid-based nanoparticles (LNPs) remains a formidable barrier to delivery. Herein, structure-activity analysis of cholesterol analogues reveals that incorporation of C-24 alkyl phytosterols into LNPs (eLNPs) enhances gene transfection and the length of alkyl tail, flexibility of sterol ring and polarity due to -OH group is required to maintain high transfection. Cryo-TEM displays a polyhedral shape for eLNPs compared to spherical LNPs, while x-ray scattering shows little disparity in internal structure. eLNPs exhibit higher cellular uptake and retention, potentially leading to a steady release from the endosomes over time. 3D single-particle tracking shows enhanced intracellular diffusivity of eLNPs relative to LNPs, suggesting eLNP traffic to productive pathways for escape. Our findings show the importance of cholesterol in subcellular transport of LNPs carrying mRNA and emphasize the need for greater insights into surface composition and structural properties of nanoparticles, and their subcellular interactions which enable designs to improve endosomal escape.

mRNA vaccines against H10N8 and H7N9 influenza viruses of pandemic potential are immunogenic and well tolerated in healthy adults in phase 1 randomized clinical trials.

BACKGROUND: We evaluated safety and immunogenicity of the first mRNA vaccines against potentially pandemic avian H10N8 and H7N9 influenza viruses. METHODS: Two randomized, placebo-controlled, double-blind, phase 1 clinical trials enrolled participants between December 2015 and August 2017 at single centers in Germany (H10N8) and USA (H7N9). Healthy adults (ages 18-64 years for H10N8 study; 18-49 years for H7N9 study) participated. Participants received vaccine or placebo in a 2-dose vaccination series 3 weeks apart. H10N8 intramuscular (IM) dose levels of 25, 50, 75, 100, and 400 µg and intradermal dose levels of 25 and 50 µg were evaluated. H7N9 IM 10-, 25-, and 50-µg dose levels were evaluated; 2-dose series 6 months apart was also evaluated. Primary endpoints were safety (adverse events) and tolerability. Secondary immunogenicity outcomes included humoral (hemagglutination inhibition [HAI], microneutralization [MN] assays) and cell-mediated responses (ELISPOT assay). RESULTS: H10N8 and H7N9 mRNA IM vaccines demonstrated favorable safety and reactogenicity profiles. No vaccine-related serious adverse event was reported. For H10N8 (N = 201), 100-µg IM dose induced HAI titers ≥ 1:40 in 100% and MN titers ≥ 1:20 in 87.0% of participants. The 25-µg intradermal dose induced HAI titers > 1:40 in 64.7% of participants compared to 34.5% of participants receiving the IM dose. For H7N9 (N = 156), IM doses of 10, 25, and 50 µg achieved HAI titers ≥ 1:40 in 36.0%, 96.3%, and 89.7% of participants, respectively. MN titers ≥ 1:20 were achieved by 100% in the 10- and 25-µg groups and 96.6% in the 50-µg group. Seroconversion rates were 78.3% (HAI) and 87.0% (MN) for H10N8 (100 µg IM) and 96.3% (HAI) and 100% (MN) in H7N9 (50 µg). Significant cell-mediated responses were not detected in either study. CONCLUSIONS: The first mRNA vaccines against H10N8 and H7N9 influenza viruses were well tolerated and elicited robust humoral immune responses. ClinicalTrials.gov NCT03076385 and NCT03345043.

Optimization of Lipid Nanoparticles for Intramuscular Administration of mRNA Vaccines.

mRNA vaccines have the potential to tackle many unmet medical needs that are unable to be addressed with conventional vaccine technologies. A potent and well-tolerated delivery technology is integral to fully realizing the potential of mRNA vaccines. Pre-clinical and clinical studies have demonstrated that mRNA delivered intramuscularly (IM) with first-generation lipid nanoparticles (LNPs) generates robust immune responses. Despite progress made over the past several years, there remains significant opportunity for improvement, as the most advanced LNPs were designed for intravenous (IV) delivery of siRNA to the liver. Here, we screened a panel of proprietary biodegradable ionizable lipids for both expression and immunogenicity in a rodent model when administered IM. A subset of compounds was selected and further evaluated for tolerability, immunogenicity, and expression in rodents and non-human primates (NHPs). A lead formulation was identified that yielded a robust immune response with improved tolerability. More importantly for vaccines, increased innate immune stimulation driven by LNPs does not equate to increased immunogenicity, illustrating that mRNA vaccine tolerability can be improved without affecting potency.

A Novel Amino Lipid Series for mRNA Delivery: Improved Endosomal Escape and Sustained Pharmacology and Safety in Non-human Primates.

The success of mRNA-based therapies depends on the availability of a safe and efficient delivery vehicle. Lipid nanoparticles have been identified as a viable option. However, there are concerns whether an acceptable tolerability profile for chronic dosing can be achieved. The efficiency and tolerability of lipid nanoparticles has been attributed to the amino lipid. Therefore, we developed a new series of amino lipids that address this concern. Clear structure-activity relationships were developed that resulted in a new amino lipid that affords efficient mRNA delivery in rodent and primate models with optimal pharmacokinetics. A 1-month toxicology evaluation in rat and non-human primate demonstrated no adverse events with the new lipid nanoparticle system. Mechanistic studies demonstrate that the improved efficiency can be attributed to increased endosomal escape. This effort has resulted in the first example of the ability to safely repeat dose mRNA-containing lipid nanoparticles in non-human primate at therapeutically relevant levels.

Boosting Intracellular Delivery of Lipid Nanoparticle-Encapsulated mRNA.

Intracellular delivery of mRNA holds great potential for vaccine1-3 and therapeutic4 discovery and development. Despite increasing recognition of the utility of lipid-based nanoparticles (LNPs) for intracellular delivery of mRNA, particle engineering is hindered by insufficient understanding of endosomal escape, which is believed to be a main limiter of cytosolic availability and activity of the nucleic acid inside the cell. Using a series of CRISPR-based genetic perturbations of the lysosomal pathway, we have identified that late endosome/lysosome (LE/Ly) formation is essential for functional delivery of exogenously presented mRNA. Lysosomes provide a spatiotemporal hub to orchestrate mTOR signaling and are known to control cell proliferation, nutrient sensing, ribosomal biogenesis, and mRNA translation. Through modulation of the mTOR pathway we were able to enhance or inhibit LNP-mediated mRNA delivery. To further boost intracellular delivery of mRNA, we screened 212 bioactive lipid-like molecules that are either enriched in vesicular compartments or modulate cell signaling. Surprisingly, we have discovered that leukotriene-antagonists, clinically approved for treatment of asthma and other lung diseases, enhance intracellular mRNA delivery in vitro (over 3-fold, p < 0.005) and in vivo (over 2-fold, p < 0.005). Understanding LNP-mediated intracellular delivery will inspire the next generation of RNA therapeutics that have high potency and limited toxicity.

Preclinical and Clinical Demonstration of Immunogenicity by mRNA Vaccines against H10N8 and H7N9 Influenza Viruses.

Recently, the World Health Organization confirmed 120 new human cases of avian H7N9 influenza in China resulting in 37 deaths, highlighting the concern for a potential pandemic and the need for an effective, safe, and high-speed vaccine production platform. Production speed and scale of mRNA-based vaccines make them ideally suited to impede potential pandemic threats. Here we show that lipid nanoparticle (LNP)-formulated, modified mRNA vaccines, encoding hemagglutinin (HA) proteins of H10N8 (A/Jiangxi-Donghu/346/2013) or H7N9 (A/Anhui/1/2013), generated rapid and robust immune responses in mice, ferrets, and nonhuman primates, as measured by hemagglutination inhibition (HAI) and microneutralization (MN) assays. A single dose of H7N9 mRNA protected mice from a lethal challenge and reduced lung viral titers in ferrets. Interim results from a first-in-human, escalating-dose, phase 1 H10N8 study show very high seroconversion rates, demonstrating robust prophylactic immunity in humans. Adverse events (AEs) were mild or moderate with only a few severe and no serious events. These data show that LNP-formulated, modified mRNA vaccines can induce protective immunogenicity with acceptable tolerability profiles.

Pharmaceutical cocrystals: along the path to improved medicines.

Cocrystals, a long known but understudied class of crystalline solids, have attracted interest from crystal engineers and pharmaceutical scientists in the past decade and are now an integral part of the preformulation stage of drug development. This is largely because cocrystals that contain a drug molecule, pharmaceutical cocrystals, can modify physicochemical properties without the need for covalent modification of the drug molecule. This review presents a brief history of cocrystals before addressing recent advances in design, discovery and development of pharmaceutical cocrystals that have occurred since an earlier review published in 2004. We address four aspects of cocrystals: nomenclature; design using hydrogen-bonded supramolecular synthons; methods of discovery and synthesis; development of pharmaceutical cocrystals as drug products. Cocrystals can be classified into molecular cocrystals (MCCs) that contain only neutral components (coformers) and ionic cocrystals (ICCs), which are comprised of at least one ionic coformer that is a salt. That cocrystals, especially ICCs, offer much greater diversity in terms of composition and properties than single component crystal forms and are amenable to design makes them of continuing interest. Seven recent case studies that illustrate how pharmaceutical cocrystals can improve physicochemical properties and clinical performance of drug substances, including a recently approved drug product based upon an ICC, are presented.

Prodrugs of pioglitazone for extended-release (XR) injectable formulations.

N-Acyloxymethyl derivatives of pioglitazone (PIO) have been prepared and characterized as model candidates for extended-release injectable formulations. All PIO derivatives prepared are crystalline solids as determined by powder X-ray diffraction, and the solubility in aqueous media is below 1 µM at 37 °C. The melting points steadily increase from 55 °C, for the hexanoyloxymethyl derivative, to 85 °C, for the palmitoyloxymethyl derivative; inversely, the solubilities in ethyl oleate decrease as a function of increasing acyl chain length. The butyroyloxymethyl ester has a higher melting point and a lower solubility in ethyl oleate than expected from the trend. The (13)C solid-state NMR spectra of the PIO homologues between the hexanoyloxymethyl derivative and stearoyloxymethyl derivative suggest a common structural motif with the acyl chains exchanging between two distinct conformations, and the rate of exchange is slower for longer chain derivatives. The butyroyloxymethyl derivative is efficiently converted to PIO in in vitro rat plasma with a half-life of <2 min at 37 (o) C, while the rate of enzymatic cleavage in rat plasma decreases as the ester chain length increases for the longer acyloxymethyl derivatives. The concentration of PIO in plasma increases rapidly, or "spikes," in the hours following intramuscular (IM) injection of either the HCl salt or the butyroyloxymethyl derivative. In contrast, the more lipophilic palmitoyloxymethyl derivative provides slow growth in the PIO concentration over the first day to reach levels that remain steady for 2 weeks. On the basis of its in vivo pharmacokinetic profile, as well as material and solubility properties, the PIO palmitoyloxymethyl derivative has potential as a once-monthly injectable medication to treat diabetes.

Long-acting atypical antipsychotics: characterization of the local tissue response.

PURPOSE: Long-acting injectables (LAIs) are increasingly recognized as an effective therapeutic approach for treating chronic conditions. Many LAIs are formulated to create a poorly soluble depot from which the active agent is delivered over time. This long residing depot can cause localized chronic-active inflammation in the tissue, which has not been well defined in the literature. The purpose of this work is to establish an experimental baseline for describing these responses. METHODS: Non-human primates and rodents were used to examine the response to LAI formulations of two clinically relevant atypical antipsychotics, aripiprazole monohydrate and olanzapine pamoate monohydrate. RESULTS: A foreign body response develops with elevations of key cytokines such as IL-1α, IL-1ß, TNFα, and IL6 at the site of injection. However, the tissue response for the two atypical antipsychotics compounds diverge as evidenced by quantitative differences observed in cytokine levels at various time points after dosing. CONCLUSIONS: Our studies show that, while the drugs are in the same therapeutic class, the response to each of these compounds can be distinguished qualitatively and quantitatively, supporting the idea that the injection site reaction involves a multiplicity of factors including the properties of the compound and cellular dynamics at the site of injection.

IP issues facing researchers by Gino D'Oca.

Patents are clearly one of the main drivers of innovation in pharmaceutical and medical R&D. It is increasingly important for researchers at the sharp end to be familiar with the ins and outs of the patenting process. In this feature a panel of experts from academia and industry discuss their experiences of analyzing the patent landscape and preparing applications. Interview conducted by Gino D'Oca, Managing Commissioning Editor.

The A to Z of pharmaceutical cocrystals: a decade of fast-moving new science and patents.

From aspirin to zoledronic acid, pharmaceutical cocrystals emerged in the past decade as a promising new weapon in the arsenal of drug development. Resurgence of interest in multicomponent crystal compositions has led to significant advances in the science of cocrystal design and discovery. These advances have built upon crystal engineering, which provides a deep understanding of supramolecular interactions between molecules that govern crystal packing and physicochemical properties of crystalline materials. Concomitantly, the patent landscape of pharmaceutical cocrystals developed rapidly in the last decade. This review presents a broad survey of patents issued in the area of pharmaceutical cocrystals. In addition, the review contains analyses of key patents in the area involving compositions and methodologies. Along the way, the main events of the past decade representing a renaissance of cocrystals of pharmaceutical materials are chronicled. Future directions in the area are discussed in light of key pending patent applications and recent publications of seminal interest.

Complexities of particulate matter measurement in parenteral formulations of small-molecule amphiphilic drugs.

Reconstituted parenteral solutions of three surface-active anti-infective small-molecule drugs and solutions of sodium dodecyl sulfate (SDS, a model surfactant) were studied to quantify the impact of sample preparation and handling on particle counts. Turbidimetry and light obscuration profiles were recorded as a function of agitation and shearing with and without the introduction of foam into the solutions. SDS solutions at concentrations above the critical micelle concentration (CMC) show significantly greater sensitivity to shear and foam presence than SDS solution below the CMC: Values of >10 µm particles increased 8 fold over control (an unsheared sample) in the micellar solution vs. 4 fold particle count increase over control at a sub-micellar concentration. An even more significant increase in the ratio of particle count in sheared/unsheared solution is seen for >25 µm unit counts, due to the increased interference of foam with the measurement. Two commercial products, injection formulations of teicoplanin and cefotaxime sodium, as well as an investigational compound 1, showed an increase in scattering as a function of foam production. The impact of foaming was significant, resulting in an increase of turbidity and light obscuration measurements in all solutions. The results illustrate some of the challenges that are inherent to optically clear, homogeneous pharmaceutical injections containing compounds which have a tendency toward self-association and surfactant-like behavior.

A high-throughput approach towards a novel formulation of fenofibrate in omega-3 oil.

A novel lipid formulation containing fenofibrate in omega-3 oil was developed using a novel high-throughput screening platform. The optimized formulation combines the cardiovascular health benefits from omega-3 oil with the potent lipid-regulating effect of fenofibrate. When tested against the current marketed product Tricor in healthy human volunteers, the new formulation was shown to be equivalent to Tricor.

Combined use of crystalline salt forms and precipitation inhibitors to improve oral absorption of celecoxib from solid oral formulations.

Biopharmaceutical evaluation of crystalline celecoxib salts in novel solid formulations, which were designed to simultaneously facilitate dissolution and inhibit precipitation in vitro, showed fast and complete absorption in beagle dogs at doses up to 7.5 mg/kg orally. In contrast, 5 mg/kg celecoxib in the form of Celebrex(R) showed approximately 40% absolute bioavailability in a cross-over experiment. An in vitro-in vivo correlation was observed in dog, and a threshold level of in vitro dissolution needed to maximize in vivo performance was highlighted. Oral bioavailability was limited in the absence of excipient combinations that delayed precipitation of celecoxib free acid as the salt neutralized in the GI fluid. Formulations of crystal forms having high energy (a 'spring'), thus transiently increasing solubility in aqueous solution relative to the free acid, combined with excipients functioning as precipitation inhibitors ('parachutes') were shown to provide both enhanced dissolution and high oral bioavailability.