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The American company, Peptimmune, designs peptide copolymers as therapeutics for diseases of the central nervous system and autoimmune disorders.

"We have an extensive knowledge of major histocompatibility complex (MHC) class II molecules, which are expressed on antigen-presenting cells such as monocytes and B lymphocytes. These molecules act as molecular support to the presentation of antigenic peptides to the immune system,” says Thomas P. Mathers, President of Peptimmune. Taking advantage of this knowledge, Peptimmune has embarked on the design of peptides targeting MHC Class II and peptides having the ability to modulate immune responses.

Peptimmune uses its proprietary DEEP technology (Directed Expansion of Epitope Permutation) for the research and development of drugs using peptide copolymers, polymers constituted of multiple variations of a particular target peptide. The platform allows the production, during a single synthesis, of mixtures of peptides incorporating at preset positions several substitutions (or permutations) of amino acids. The resulting products are mixtures of thousands or even millions of similar but different peptides that are highly immunogenic and capable of inducing a targeted immune response.

Peptimmune’s flagship product, PI-2301, is a copolymer consisting of long peptide chains but incorporating only four amino acids. PI-2301 is currently under clinical evaluation in patients suffering from the secondary progressive form of multiple sclerosis (MS). This autoimmune disease results from an abnormal activation of the immune system attacking the myelin sheath of neurons and resulting in loss of motor function and sensitivity. Through its binding to MHC class II molecules, PI-2301 interferes with the autoimmune activity of lymphocytes from these patients in order to arrest disease progression.  Derived from the original works performed in the laboratory of Jack Strominger, a professor of biochemistry at Harvard University and Professor Hidde Ploegh of the Whitehead Institute for Biomedical Research at MIT, Peptimmune has been funded since its inception in 2002 by private investors and is based in Cambridge, Massachusetts.

Co-development policy

"Peptimmune is a clinical stage biotechnology company. A Phase Ib study aimed to investigate the safety and pharmacological mechanism of PI-2301 in patients with secondary progressive MS is ongoing at several sites in France. PI-2301 has the potential to replace Copaxone, the most used drug for the treatment of MS with annual revenues of 1.6 billion euros," says Mr.Mathers. Peptimmune has recently granted an exclusive option to license PI-2301 to Novartis, which, if exercised, should assume the global clinical development, manufacturing and marketing of PI-2301 as a treatment for MS.

Beside the therapeutic applications of PI-2301 in other autoimmune diseases, peptide copolymers have great potential for the development of diagnostic tests, as targets for the production of new therapeutic antibodies or as “universal” vaccines in certain infectious diseases in which the pathogenic agent is constantly mutating. These new applications of the DEEP platform predict a bright future for Peptimmune.