Xenetic Biosciences

Xenetic (formerly Lipoxen) is a leading UK based biopharmaceutical company providing leading edge expertise in the development of a whole new generation of drugs and vaccines.

Working with some of the largest pharmaceutical organisations in the world, Xenetic provides specialist delivery solutions to improve the efficacy and performance of drugs and vaccines in a number of key medical areas.

We are also actively developing our own pipeline of next generation biotherapeutics based on our proprietary PolyXen and ImuXen platform technologies.

Xenetic has developed a number of proprietary patented technologies that are being used to create a new generation of drug and vaccine products with improved performance. Xenetic’s technologies include:

PolyXen® for protein drug delivery

PolyXen® is a versatile enabling technology that uses the biopolymer polysialic acid to prolong the active life and improve the pharmacokinetics and pharmacodynamics of therapeutic peptides and proteins, as well as conventional small molecule drugs.  PolyXen® is  a next generation method to PEGylation for the delivery of protein drugs.

ImuXen® for vaccine delivery

ImuXen® is an advanced enabling technology that uses liposome-based constructs to boost the effectiveness of DNA, protein and polysaccharide vaccines.  ImuXen® can achieve protective immunity in a single dose.

Oncohist

Oncohist (recombinant human Histone H 1.3) is a novel biotherapeutic molecule for the treatment of tumours, in particular, haematologic malignancies.  Histone H1 molecules have evolved to recognise and destabilise the membranes of tumour cells and micro-organisms displaying aberrant membrane characteristics.  Oncohist has the same properties as the body's own histone H1 molecules.  Oncohist has superior advantages over conventional cancer therapeutics, including high selectivity, low inherent toxicity, lack of induction of resistance and low immunogenicity.

PolyXen

PolyXen® is an enabling technology for protein drug delivery.  It uses the natural polymer polysialic acid (PSA) to prolong the active life and improve the stability of therapeutic peptides and proteins.  It can also be used for small molecule drugs.

PolyXen® is an enabling technology for protein drug delivery.  It uses the natural polymer polysialic acid (PSA) to prolong the active life and improve the stability of therapeutic peptides and proteins.  It can also be used for small molecule drugs.

Pre-clinical proof-of-concept studies and clinical studies in man have shown that the key benefits of PolyXen® for protein drug delivery include:

• Preservation of drug functionality on conjugation
• Improved stability in vivo
• Prolonged pharmacological action
• Prolonged active life of the drug in the blood circulation
• Reduced frequency and amount of dosage
• Reduced immunogenicity and antigenicity

What is polysialic acid?

PSA is a polymer of sialic acid (a sugar).  When used for therapeutic protein and peptide drug delivery, polysialic acid provides a protective microenvironment following conjugation to the active drug.  This increases the active life of the therapeutic drug in the body and prevents it from being recognized by the immune system.

The PSA polymer is naturally found in the human body.  However, PSA actually evolved millions of years ago as part of the coat on the external walls of certain bacteria. By virtue of molecular mimicry with human PSA, these naturally polysialylated bacteria are able to foil the body’s defences and can exist largely undetected by the immune system. Xenetic are producing PSA, nature's ultimate stealth technology, from such bacteria in large quantities and with predetermined physical characteristics. Bacterial PSA is an ideal polymer for drug conjugation as it is non-toxic, biodegradable and completely non-immunogenic, even when coupled to proteins, due to it being chemically identical to PSA found in the human body. This is particularly important where a polymer is to be used to deliver therapeutics chronically or in large dosages

How does PolyXen® technology use polysialic acid?

PolyXen® uses proprietary techniques to conjugate polysialic acid molecules of appropriate length to specific sites of the therapeutic molecule, but importantly, away from its active site to preserve activity.  The PSA molecules form a glycocalyx (a carbohydrate shield) around the therapeutic rendering it less visible to and reducing the risk of recognition by the body’s immune system.

For more information about PolyXen® please click here.

ImuXen

ImuXen® is a liposomal technology platform designed to improve the delivery and effectiveness of DNA, protein and polysaccharide vaccines.

Proof of concept preclinical studies with a number of vaccines have shown that ImuXen® technology can help to generate the rapid onset of protective immune responses, in some cases following just a single dose

The advantages of ImuXen® for DNA, protein and polysaccharide vaccines include:

• Efficient delivery of vaccine antigens to the immune system
• Enhanced immune responses
• Protective immunity after a single injection
• Protection of vaccine against degradation during storage
• Rapid, simple and scalable manufacture
• How does liposomal vaccine delivery work?

Liposomes are microscopic spheres typically consisting of a bi-layer of naturally occurring lipids with a central aqueous core.  Xenetic’s proprietary techniques allow the rapid and simple entrapment of DNA, protein and polysaccharide antigens within the aqueous core of liposomes, creating vaccines that induce protective immunity through the generation of enhanced immune responses. Because the lipids used to create Xenetic’s liposomes occur naturally in nature and the antigens are entrapped within the liposomal core, ImuXen® vaccines greatly reduce the side effects associated with conventional vaccines, including minimising injection site reactions and reducing the risk of anaphylaxis.

How does ImuXen® improve liposomal vaccine delivery?

Although the use of liposomes to administer vaccines is not a new process, conventional liposomal vaccines are based on the delivery of DNA or protein antigens alone. This can produce weak or inappropriate immune responses and may require multiple doses to achieve effective immunity. In contrast, ImuXen® can deliver effective immunity following a single dose.

ImuXen® is based on proprietary techniques that allow the entrapment of vaccine antigens within liposomes with carefully defined and controlled characteristics.  This process can be used to create and deliver DNA, protein and polysaccharide-based vaccines capable of generating enhanced immune responses.

• Proof of concept preclinical studies have shown that the benefits of ImuXen® vaccines include:
• Reduction in the number of doses required
• Reduction in side effects
• Potential for oral administration of vaccines
• Potential for multiple vaccines to be delivered in the same injection

How does ImuXen® work with DNA-based vaccines?

A ground-breaking aspect of ImuXen® is the co-entrapment of a plasmid DNA along with the protein antigen it encodes within the same liposome.  This is Xenetic’s proprietary ‘co-delivery’ technology.  Studies have repeatedly shown that a single injection of a co-delivery formulation can generate faster and stronger immune responses than those obtained following multiple injections of liposomes incorporating either the plasmid DNA or the protein antigen alone or even if the two individual formulations are mixed and injected together.  It is the co-delivery of the complimentary antigens within the same liposome that makes the key difference. This approach to vaccination mimics the way immunity is achieved by live viruses.  In viral infections, the nucleic acids (DNA or in some cases, RNA) and the proteins they encode both contribute to the immune response against the virus.

Xenetic’s vaccines can be further advanced by coating ImuXen® liposomes with a sugar known as mannose.  Mannose-coated liposomes are specifically targeted to cells of the immune system displaying receptors on their surface designed to recognise mannose molecules.  This promotes uptake of the liposomes by these immune cells, further stimulating the immune responses to the vaccine.

How does ImuXen® work in polysaccharide vaccines?

ImuXen® co-delivery technology can also be used to create liposome-based polysaccharide vaccines capable of inducing long-lasting protective immunity.

Conventional multivalent polysaccharide-based vaccines (such as pneumococcal vaccines) are usually administered as a mixture of polysaccharides derived from a specific number of strains of the infectious organism.  Such vaccines are designed to protect against infection with the most common strains of the organism but typically produce immune responses that are only transient in adults and inefficient in infants.  To achieve more lasting protective immune responses, a process known as conjugation is used to chemically attach each of the polysaccharides to a carrier protein.

Chemical conjugation requires complex and expensive technologies.  However ImuXen® provides an improved method of formulating polysaccharide vaccines, and uses a co-delivery process which is efficient and common to all polysaccharides.  This involves the simple co-entrapment of each of the polysaccharide types together with a carrier protein in individual liposome preparations. These liposomal preparations are then pooled to provide a multivalent vaccine. Importantly, the requirement for any chemical conjugation is removed by the process of co-entrapment.  Proof of concept studies have shown that multivalent polysaccharide vaccines made in this way are as efficacious as their chemically constructed counterparts.

For more information regarding ImuXen® please click here.

Protein drugs and vaccines

Xenetic’s biopharmaceutical pipeline contains a range of product candidates which are currently under development either in-house or with biotechnology and pharmaceutical partners.  The products in Xenetic’s pipeline have a multi-billion dollar market potential.

Pipeline products are based on Xenetic’s proprietary drug and vaccine delivery technologies and have been developed to offer improved performance and delivery characteristics.  Xenetic’s unique delivery technologies are also able to create new high-value, differentiated proprietary products from off-patent actives.

Xenetic has established a range of partnerships with major US, European, Russian and Asian biotechnology and pharmaceutical companies to develop new protein therapeutics and vaccines.  Click here to learn more about the work we do with our partners.

For more information about Xenetic's products please click here.