Protein-polyanion interactions for the controlled release of monoclonal antibodies

Local controlled release of stabilized monoclonal antibodies

Monoclonal antibody (mAb) therapeutics have become widely successful for treatment of any number of diseases. However, for certain hard-to-reach tissues, e.g., eye, brain, tumors, and joints, local delivery is desired and long-term controlled release is necessary to avoid frequent injections and poor patient compliance. If local and sustained exposure of mAbs (or their Fab or nanobody fragments) could be accomplished by injectable polymer long-acting release (LAR) systems, the incredible potential of mAb therapeutics could be extended to additional diseases, e.g., neovascular age-related macular degeneration (wet AMD) and glioblastoma multiforme (GBM). In prior studies, long-acting delivery of mAbs has been limited by the inability to design a delivery system prepared from a biodegradable polymer used in FDA-approved LARs that achieves long-term continuous release of structurally stable and immunoreactive mAb with a low initial burst release that is easily injectable and avoids material build-up upon repeated injection. Here, we present for the first time a long-acting delivery system capable of delivering several different mAbs for multiple indications by developing a novel process to stabilize mAbs through the combination of formulation, micronization and encapsulation conditions, and to control stabilized mAb exposure in vivo for months by formulation with an appropriate biodegradable polymer (poly(lactic-co-glycolic acid) (PLGA)), utilization of a pH- and pore-modifying agent, and development of a novel PLGA coating layer to control osmotic pressure induced by elevated levels of critical co-encapsulated stabilizers, particularly mAb-stabilizing-trehalose. The resulting implants showed long-term efficacy in animal models for both wet AMD and GBM after single local injections. Although much more work needs to be done before their clinical application to these two diseases, the injectable PLGA platform meets several important benchmarks for controlled mAb delivery and can be developed further for delivery of a wide array of mAbs and other cofactors, offering an improved therapeutic option for treating diseases amenable to local antibody therapy. One Sentence Summary: A generalizable injectable biodegradable PLGA implant platform for site-specific and long-term slow and continuous release of stabilized monoclonal antibody drugs demonstrates improved in vivo efficacy for wet AMD and glioblastoma.

Subcutaneous delivery of an antibody against SARS-CoV-2 from a supramolecular hydrogel depot

Prolonged maintenance of therapeutically-relevant levels of broadly neutralizing antibodies (bnAbs) is necessary to enable passive immunization against infectious disease. Unfortunately, protection only lasts for as long as these bnAbs remain present at a sufficiently high concentration in the body. Poor pharmacokinetics and burdensome administration are two challenges that need to be addressed in order to make pre- and post-exposure prophylaxis with bnAbs feasible and effective. In this work, we develop a supramolecular hydrogel as an injectable, subcutaneous depot to encapsulate and deliver antibody drug cargo. This polymer-nanoparticle (PNP) hydrogel exhibits shear-thinning and self-healing properties that are required for an injectable drug delivery vehicle. In vitro drug release assays and diffusion measurements indicate that the PNP hydrogels prevent burst release and slow the release of encapsulated antibodies. Delivery of bnAbs against SARS-CoV-2 from PNP hydrogels is compared to standard routes of administration in a preclinical mouse model. We develop a multi-compartment model to understand the ability of these subcutaneous depot materials to modulate the pharmacokinetics of released antibodies; the model is extrapolated to explore the requirements needed for novel materials to successfully deliver relevant antibody therapeutics with different pharmacokinetic characteristics.

An ameliorated anti-hTNF-α therapy for arthritis via carrier-free macromolecular nanoparticles consisted of infliximab

Infliximab (INF) is intravenously used for the clinical treatment of rheumatoid arthritis. However, it can cause serious side effects, which are mainly associated with systemic exposure and high doses. Here, we developed a modified hydrophobic ion-pairing complexes (INF HIPC) through the sequential introduction of bovine lactoferrin (BLF) and hyaluronic acid (HA) with opposite charges into the INF solution. INF and BLF were found to be not only integrally responsible for the structural integrity of HIPC but also were determined to have respective biological activities by binding human tumor necrosis factor-alpha (hTNF-α) or promoting the proliferation of osteoblasts. The INF HIPC had good stability, high drug-loading efficiency, and long-term retention effects. Whether via knee joint injection or intravenous injection, INF HIPC resulted in lower hTNF-α levels and less cartilage destruction than INFs in the transgenic mouse model. At the same time, INF HIPC could reduce toxicity based on body weight changes in transgenic mice. Our findings provide a simple and promising avenue to develop advanced delivery systems for other antibodies and macromolecules.

Advanced Formulations/Drug Delivery Systems for Subcutaneous Delivery of Protein-Based Biotherapeutics

Multiple advanced formulations and drug delivery systems (DDSs) have been developed to deliver protein-based biotherapeutics via the subcutaneous (SC) route. These formulations/DDSs include high-concentration solution, co-formulation of two or more proteins, large volume injection, protein cluster/complex, suspension, nanoparticle, microparticle, and hydrogel. These advanced systems provide clinical benefits related to efficacy and safety, but meanwhile, have more complicated formulations and manufacturing processes compared to conventional solution formulations. To develop a fit-for-purpose formulation/DDS for SC delivery, scientists need to consider multiple factors, such as the primary indication, targeted site, immunogenicity, compatibility, biopharmaceutics, patient compliance, etc. Next, they need to develop appropriate formulation (s) and manufacturing processes using the QbD principle and have a control strategy. This paper aims to provide a comprehensive review of advanced formulations/DDSs recently developed for SC delivery of proteins, as well as some knowledge gaps and potential strategies to narrow them through future research.

Subcutaneous delivery of an antibody against SARS-CoV-2 from a supramolecular hydrogel depot

Prolonged maintenance of therapeutically-relevant levels of broadly neutralizing antibodies (bnAbs) is necessary to enable passive immunization against infectious disease. Unfortunately, protection only lasts for as long as these bnAbs remain present at a sufficiently high concentration in the body. Poor pharmacokinetics and burdensome administration are two challenges that need to be addressed in order to make pre- and post-exposure prophylaxis with bnAbs feasible and effective. In this work, we develop a supramolecular hydrogel as an injectable, subcutaneous depot to encapsulate and deliver antibody drug cargo. This polymer-nanoparticle (PNP) hydrogel exhibits shear-thinning and self-healing properties that are required for an injectable drug delivery vehicle. In vitro drug release assays and diffusion measurements indicate that the PNP hydrogels prevent burst release and slow the release of encapsulated antibodies. Delivery of bnAbs against SARS-CoV-2 from PNP hydrogels is compared to standard routes of administration in a preclinical mouse model. We develop a multi-compartment model to understand the ability of these subcutaneous depot materials to modulate the pharmacokinetics of released antibodies; the model is extrapolated to explore the requirements needed for novel materials to successfully deliver relevant antibody therapeutics with different pharmacokinetic characteristics.

Recent Progress on Polysaccharide-Based Hydrogels for Controlled Delivery of Therapeutic Biomolecules

A plethora of applications using polysaccharides have been developed in recent years due to their availability as well as their frequent nontoxicity and biodegradability. These polymers are usually obtained from renewable sources or are byproducts of industrial processes, thus, their use is collaborative in waste management and shows promise for an enhanced sustainable circular economy. Regarding the development of novel delivery systems for biotherapeutics, the potential of polysaccharides is attractive for the previously mentioned properties and also for the possibility of chemical modification of their structures, their ability to form matrixes of diverse architectures and mechanical properties, as well as for their ability to maintain bioactivity following incorporation of the biomolecules into the matrix. Biotherapeutics, such as proteins, growth factors, gene vectors, enzymes, hormones, DNA/RNA, and antibodies are currently in use as major therapeutics in a wide range of pathologies. In the present review, we summarize recent progress in the development of polysaccharide-based hydrogels of diverse nature, alone or in combination with other polymers or drug delivery systems, which have been implemented in the delivery of biotherapeutics in the pharmaceutical and biomedical fields.

Local administration and enhanced release of bone metabolic antibodies from hydroxyapatite/chondroitin sulfate nanocomposite microparticles using zinc cations

As a local delivery carrier of bone metabolic proteins, we have previously reported hydroxyapatite/chondroitin sulfate composite microparticles (HAp/ChS) and their formulation method using zinc cations (Zn), and the in vitro release properties of proteins from the microparticles. Herein, we report the release properties of model antibodies such as immunoglobulin (IgG), human IgG (hIgG), and denosumab (Dmab) from HAp/ChS using this formulation method. Adding Zn in the formulation of IgG loaded with HAp/ChS microparticles enhanced the release of antibodies from HAp/ChS in phosphate buffer saline. In addition, the biological activity of Dmab released from HAp/ChS formulated with Zn was significantly higher than that without Zn. These results suggest a possible beneficial effect on the treatment for local bone diseases. The sclerostin monoclonal antibody (Sclmab) promotes fracture healing. We prepared HAp/ChS microparticles loaded with Sclmab and locally administered the microparticles into a drilled hole in the distal femoral bone of young rats. After three weeks, the area of the newly formed osteoid around the drilled hole where HAp/ChS loaded with Sclmab and Zn was locally administered was significantly higher than that observed in the control group (normal saline). Thus, HAp/ChS microparticles and the formulation method of monoclonal antibodies using Zn could be useful in the treatment of local bone diseases.

Contribution of Intrinsic Fluorescence to the Design of a New 3D-Printed Implant for Releasing SDABS

Single-domain antibodies (sdAbs) offer great features such as increased stability but are hampered by a limited serum half-life. Many strategies have been developed to improve the sdAb half-life, such as protein engineering and controlled release systems (CRS). In our study, we designed a new product that combined a hydrogel with a 3D-printed implant. The results demonstrate the implant’s ability to sustain sdAb release up to 13 days through a reduced initial burst release followed by a continuous release. Furthermore, formulation screening helped to identify the best sdAb formulation conditions and improved our understanding of our CRS. Through the screening step, we gained knowledge about the influence of the choice of polymer and about potential interactions between the sdAb and the polymer. To conclude, this feasibility study confirmed the ability of our CRS to extend sdAb release and established the fundamental role of formulation screening for maximizing knowledge about our CRS.

In situ chemically crosslinked injectable hydrogels for the subcutaneous delivery of trastuzumab to treat breast cancer

Recently, novel approaches for the delivery of therapeutic antibodies have attracted much attention, especially sustained release formulations. However, sustained release formulations capable of carrying a high antibody load remain a challenge for practical use. In this study, a novel injectable hydrogel composed of maleimide-modified γ-polyglutamic acid (γ-PGA-MA) and thiol end-functionalized 4-arm poly(ethylene glycol) (4-arm PEG-SH) was developed for the subcutaneous delivery of trastuzumab. γ-PGA-MA and 4-arm PEG-SH formed a hydrogel through thiol-maleimide reactions, which had shear-thinning properties and reversible rheological behaviors. Moreover, a high content of trastuzumab (>100 mg/mL) could be loaded into this hydrogel, and trastuzumab demonstrated a sustained release over several weeks through electrostatic attraction. In addition, trastuzumab released from the hydrogel had adequate stability in terms of its structural integrity, binding bioactivity, and antiproliferative effect on BT-474 cells. Pharmacokinetic studies demonstrated that trastuzumab-loaded hydrogel (Her-hydrogel-10, composed of 1.5% γ-PGA-MA, 1.5% 4-arm PEG-SH, and 10 mg/mL trastuzumab) and trastuzumab/Zn-loaded hydrogel (Her/Zn-hydrogel-10, composed of 1.5% γ-PGA-MA, 1.5% 4-arm PEG-SH, 5 mM ZnCl₂, and 10 mg/mL trastuzumab) could lower the maximum plasma concentration (C_max) than the trastuzumab solution. Furthermore, Her/Zn-hydrogel-10 was better able to release trastuzumab in a controlled manner, which was ascribed to electrostatic attraction and formation of trastuzumab/Zn nanocomplexes. In a BT-474 xenograft tumor model, Her-hydrogel-10 had a similar tumor growth-inhibitory effect as that of the trastuzumab solution. By contrast, Her/Zn-hydrogel-10 exhibited a superior tumor growth-inhibitory capability due to the functionality of Zn. This study demonstrated that this hydrogel has potential as a carrier for the local and systemic delivery of proteins and antibodies. STATEMENT OF SIGNIFICANCE: Recently, novel sustained-release formulations of therapeutic antibodies have attracted much attention. However, these formulations should be able to carry a high antibody load owing to the required high dose, and these formulations remain a challenge for practical use. In this study, a novel injectable chemically cross-linked hydrogel was developed for the subcutaneous delivery of trastuzumab. This novel hydrogel possessed ideal characteristics of loading high content of trastuzumab (>100 mg/mL), sustained release of trastuzumab over several weeks, and maintaining adequate stability of trastuzumab. In vivo studies demonstrated that a trastuzumab-loaded hydrogel possessed the ability of controlled release of trastuzumab and maintained antitumor efficacy same as that of trastuzumab. These results implied that a γ-PGA-MA and 4-arm PEG-SH-based hydrogel has great potential in serving as a carrier for the local or systemic delivery of therapeutic proteins or antibodies.

Sustained delivery of anti-VEGF from injectable hydrogel systems provides a prolonged decrease of endothelial cell proliferation and angiogenesis in vitro

Therapeutic antibodies are attractive treatment options for numerous diseases based on their ability to target and bind to specific proteins or antigens. Bevacizumab, an antiangiogenic antibody, has shown promise for multiple diseases, including various cancers and macular degeneration, where excessive VEGF secretion induces aberrant angiogenesis. In many cases local, sustained delivery of a therapeutic antibody would be preferable to maximize the therapeutic at the disease site, eliminate the need for repeated doses, and reduce systemic side effects. The biodegradable polysaccharides alginate and chitosan can electrostatically interact to form a polyelectrolyte complex (PEC), and have proved effective as a carrier for controlled release of antibodies. In this work, an alginate–chitosan PEC system was designed to produce targeted 30-day delivery of non-specific IgG and anti-VEGF antibodies. The release of anti-VEGF was slow relative to IgG release, suggesting that release rate is antibody specific and is based on the interactions of the PEC with charges present on the antibody surface. The anti-VEGF released from the PEC was shown to successfully inhibit VEGF-induced proliferation and angiogenesis in vitro throughout the 30-day test period.

Sustained delivery of bioactive anti-VEGF antibodies is demonstrated using a polyelectrolyte complex of alginate and chitosan. The released anti-VEGF inhibited VEGF induced-proliferation and angiogenesis in HUVECs over a 30-day period.

The state-of-play and future of antibody therapeutics

It has been over four decades since the development of monoclonal antibodies (mAbs) using a hybridoma cell line was first reported. Since then more than thirty therapeutic antibodies have been marketed, mostly as oncology, autoimmune and inflammatory therapeutics. While antibodies are very efficient, their cost-effectiveness has always been discussed owing to their high costs, accumulating to more than one billion dollars from preclinical development through to market approval. Because of this, therapeutic antibodies are inaccessible to some patients in both developed and developing countries. The growing interest in biosimilar antibodies as affordable versions of therapeutic antibodies may provide alternative treatment options as well potentially decreasing costs. As certain markets begin to capitalize on this opportunity, regulatory authorities continue to refine the requirements for demonstrating quality, efficacy and safety of biosimilar compared to originator products. In addition to biosimilars, innovations in antibody engineering are providing the opportunity to design biobetter antibodies with improved properties to maximize efficacy. Enhancing effector function, antibody drug conjugates (ADC) or targeting multiple disease pathways via multi-specific antibodies are being explored. The manufacturing process of antibodies is also moving forward with advancements relating to host cell production and purification processes. Studies into the physical and chemical degradation pathways of antibodies are contributing to the design of more stable proteins guided by computational tools. Moreover, the delivery and pharmacokinetics of antibody-based therapeutics are improving as optimized formulations are pursued through the implementation of recent innovations in the field.

Silica microparticles for sustained zero-order release of an anti-CD40L antibody

Silica microparticle hydrogel depot (HG) formulation was prepared using spray drying of silica-based sol-gels for the sustained delivery of MR1 antibody which binds to CD40 ligand (CD40L). The formulation was tested in vitro for antibody release, surface morphology, particle size, rheology, and injectability. In vivo pharmacokinetic evaluation was performed for the microparticle formulation and free MR1 antibody in BALB/c female mice. Serum samples up to day 62 were assessed using an enzyme-linked immunosorbent assay. In vitro release indicated that the MR1 antibody was uniformly encapsulated in silica microparticles, and less than 5% burst release of the antibody was observed. In vivo pharmacokinetics showed a zero-order release up to 62 days from the MR1 silica microparticle HG-controlled release composition.

Synthetic Biomaterials from Metabolically Derived Synthons

The utility of metabolic synthons as the building blocks for new biomaterials is based on the early application and success of hydroxy acid based polyesters as degradable sutures and controlled drug delivery matrices. The sheer number of potential monomers derived from the metabolome (e.g., lactic acid, dihydroxyacetone, glycerol, fumarate) gives rise to almost limitless biomaterial structural possibilities, functionality, and performance characteristics, as well as opportunities for the synthesis of new polymers. This review describes recent advances in new chemistries, as well as the inventive use of traditional chemistries, toward the design and synthesis of new polymers. Specific polymeric biomaterials can be prepared for use in varied medical applications (e.g., drug delivery, tissue engineering, wound repair, etc.) through judicious selection of the monomer and backbone linkage.

Overcoming the challenges in administering biopharmaceuticals: formulation and delivery strategies

The formulation and delivery of biopharmaceutical drugs, such as monoclonal antibodies and recombinant proteins, poses substantial challenges owing to their large size and susceptibility to degradation. In this Review we highlight recent advances in formulation and delivery strategies--such as the use of microsphere-based controlled-release technologies, protein modification methods that make use of polyethylene glycol and other polymers, and genetic manipulation of biopharmaceutical drugs--and discuss their advantages and limitations. We also highlight current and emerging delivery routes that provide an alternative to injection, including transdermal, oral and pulmonary delivery routes. In addition, the potential of targeted and intracellular protein delivery is discussed.

Prevention of thermally induced aggregation of IgG antibodies by noncovalent interaction with poly(acrylate) derivatives

Prevention of thermal aggregation of antibodies in aqueous solutions was achieved by noncovalent association with hydrophobically modified poly(acrylate) copolymers. Using a polyclonal immunoglobin G (IgG) as a model system for antibodies, we have studied the mechanisms by which this multidomain protein interacts with polyanions when incubated at physiological pH and at temperatures below and above the protein unfolding/denaturation temperature, in salt-free solutions and in 0.1 M NaCl solutions. The polyanions selected were sodium poly(acrylates), random copolymers of sodium acrylate and N-n-octadecylacrylamide (3 mol %), and a random copolymer of sodium acrylate, N-n-octylacrylamide (25 mol %), and N-isopropylacrylamide (40 mol %). They were derived from two poly(acrylic acid) parent chains of Mw 5000 and 150000 g·mol(-1). The IgG/polyanion interactions were monitored by static and dynamic light scattering, fluorescence correlation spectroscopy, capillary zone electrophoresis, and high sensitivity differential scanning calorimetry. In salt-free solutions, the hydrophilic PAA chains form complexes with IgG upon thermal unfolding of the protein (1:1 w/w IgG/PAA), but they do not interact with native IgG. The complexes exhibit a remarkable protective effect against IgG aggregation and maintain low aggregation numbers (average degree of oligomerization <12 at a temperature up to 85 °C). These interactions are screened in 0.1 M NaCl and, consequently, PAAs lose their protective effect. Amphiphilic PAA derivatives (1:1 w/w IgG/polymer) are able to prevent thermal aggregation (preserving IgG monomers) or retard aggregation of IgG (formation of oligomers and slow growth), revealing the importance of both hydrophobic interactions and modulation of the Coulomb interactions with or without NaCl present. This study leads the way toward the design of new formulations of therapeutic proteins using noncovalent 1:1 polymer/protein association that are transient and require a markedly lower additive concentration compared to conventional osmolyte protecting agents. They do not modify IgG permanently, which is an asset for applications in therapeutic protein formulations since the in vivo efficacy of the protein should not be affected.

Pharmacokinetics, biocompatibility and bioavailability of a controlled release monoclonal antibody formulation

The sustained and localized delivery of monoclonal antibodies has become highly relevant, because of the increasing number of investigated local delivery applications in recent years. As the local delivery of antibodies is associated with high technological hurdles, very few successful approaches have been reported in the literature so far. Alginate-based delivery systems were previously described as promising sustained release formulations for monoclonal antibodies (mAbs). In order to further investigate their applicability, a single-dose animal study was conducted to compare the biocompatibility, the pharmacokinetics and the bioavailability of a human monoclonal antibody liquid formulation with two alginate-based sustained delivery systems after subcutaneous administration in rats. 28 days after injection, the depot systems were still found in the subcutis of the animals. A calcium cross-linked alginate formulation, which was injected as a hydrogel, was present as multiple compartments separated by subcutaneous tissue. An in situ forming alginate formulation was recovered as a single compact and cohesive structure. It can be assumed that the multiple compartments of the hydrogel formulation led to almost identical pharmacokinetic profiles for all tested animals, whereas the compact nature of the in situ forming system resulted in large interindividual variations in pharmacokinetics. As compared to the liquid formulation the hydrogel formulations led to lower mAb serum levels, and the in situ forming system to a shift in the time to reach the maximum mAb serum concentration (Tmax) from 2 to 4 days. Importantly, it was shown that after 28 days only marginal amounts of residual mAb were present in the alginate matrix and in the tissue at the injection site indicating nearly complete release. In line with this finding, systemic drug bioavailability was not affected by using the controlled release systems. This study successfully demonstrates the suitability and underlines the potential of polyanionic systems for local and controlled mAb delivery.