AIDS, Microparticles useful in the delivery of antigens for prophylaxis and treatment of HIV

Polymeric microparticles encapsulating peptide antigens as delivery systems for their capability to efficiently target the antigen to professional antigen-presenting cells.

It is important that therapeutic or prophylactic peptides, and in particular vaccines, are efficiently delivered to their site of action without significant degradation. Polymeric microparticles encapsulating peptide antigens have been investigated as potential delivery systems for their capability to efficiently target the antigen to professional antigen- presenting cells and to release it in a controlled way over a prolonged period of time. Although peptides encapsulated into a microparticulate matrix may be protected from unfavorable conditions encountered after parenteral or mucosal administration, they often become unstable or are degraded. This may occur either during the encapsulation process, such as the exposure to organic solvents, high shear and freeze-drying, and/or in the body when the antigen is exposed to the low pH microenvironment caused by the degradation of the polymer. The inventors have found that antigens may be fixed or adsorbed to the external surface of polymeric microparticles. Further the inventors have shown that these microparticles may be used to efficiently deliver antigens to target cells. Accordingly the invention provides a microparticle comprising: (a) a core which comprises a water insoluble polymer or copolymer, and (b) a shell which comprises a hydrophilic polymer or copolymer and functional groups which are ionic or ionisable; and said microparticle having a disease-associated antigen adsorbed at the external surface. Key applications The invention further provides: a method of production of a microparticle of invention; a pharmaceutical composition comprising a microparticle of the invention; a method of generating an immune response in an individual, said method comprising administering a microparticle of the invention in a therapeutically effective amount; a method of preventing or treating HIV infection or AIDS, said method comprising administering a microparticle of the invention in a therapeutically effective amount. a microparticle of the invention for use in a method of treatment of the human or animal body by therapy or diagnosis; use of a microparticle of the invention for the manufacture of a medicament for generating an immune response in an individual; and use of a microparticle of the invention for the manufacture of a medicament for preventing or treating HIV infection or AIDS. Stage of Development: The technology is in the pre-clinical stage with in vivo animal studies completed.

Preclinical

Priority Filing in UK in Nov.3, 2003 - PCT Stage, published

Delopmental Partnership, Outlicense, Sale