Biological therapeutics is essentially based on large proteins molecules isolated from micro-organisms or with recombinant DNA technology expressed in microorganisms. These protein molecules are made of linear chain amino acids in a way that is determined by the gene sequence encoded in their genetic code. Biological therapeutics is made using fermentation technology.

Although some therapeutic drugs are also isolated through microbial fermentation, they differ from biological therapeutics in that the former are mostly small heterocyclic cytotoxic organic molecules with molecular weight of 1000-2000. By this definition, an example of a therapeutic drug that does not fall in the biological therapeutic category is the bactericidal agent streptomycin that is isolated from the bacteria of the Streptomyces genus, or Mylotarg for cancer therapy that is isolated from the bacterium Micromonospora echinospora.

Biological therapeutics has enhanced our understanding of the disease mechanisms prevalent in autoimmune diseases and therefore newer biologicals are appearing in the marketplace. For example, in the context of autoimmune diseases, the idea is to create biological therapeutic agents with less toxicity but offering better control over chronic inflammatory processes.

Here are a few examples of biological therapeutics.

Collagenases

These denote the enzyme group (endopeptidases) manufactured by Clostridium genus, a bacterial pathogen. Collagenases are capable of digesting native collagen in the triple helix region. For example, the debriding ointment Santyla is capable of digesting collagen in necrotic tissue and prevents tissue damage that could cause serious problems. Santyla contains Collagenase isolated from Clostridium histolyticum and it could be used in necrosis and wounds that are not healed properly and where there is a need to remove dead skin. The reason why medicines like Santyla are effective is not only due to the ability of collagenase to digest collagen but also due to the fact that three fourths of the dry weight of human skin tissue is due to collagen.An advantage with the biological therapeutic medicine collagenase is that it isn't toxic and it doesn't get absorbed through the skin and hence doesn't get into the body fluids.

Iruxola made by Knoll Pharmaceuticals and which contains Collagenase Clostridiopeptidase and proteases is another similar product. Other collagenases are undergoing clinical trials for treating lipomas (benign fatty bulges under the skin); cellulite (thigh and buttocks skin dimpling);and for frozen shoulder(shoulder inflammation).

Recombinant proteins

They are made from bacteria like E.coli, Pseudomonas fluorescens and Yeast and they don't have the complications that are typical to non human proteins like immunogenic complications. One example is the lysostaphin naturally produced by Staphylococcus simulans; another example is recombinant FGF especially good for wound healing and cartilage injuries.

Another example is the use of antibody fragments which means using small portion of the antibody and not the full length. E. coli, yeasts, and fungi are used for making antibody fragments. For example Nanobodiesa made by Ablynx are being clinically evaluated for cardiovascular and neurological illnesses. Another example is Genentech's Lucentisa (ranibizumab injection), which is a recombinant humanized IgG1 kappa isotype monoclonal antibody fragment designed for intraocular use.

Other Immunosuppressive agents

Immunosuppressive drugs have been usually used against autoimmune diseases but they have several side effects. An ideal drug for treating autoimmune disease would be one that specifically targets chronic inflammation cells but should not have other effects on immune system.

As of today, our understanding of human autoimmune disease is insufficient, but what we know for certain is that the underlying mechanism through which human body offers immunity against foreign microorganisms entering the body is the same mechanism that destroys organs and tissues when an autoimmune disease occurs. And it is CD4+ T cells (activated by a peptide recognized by their T cell receptor) in the human body that is responsible for directing these immune responses.

When activated, CD4+ T cells regulate a specific immune response and so activated CD4+ T cells can be found in inflammations of autoimmune diseases and therefore have a role in providing autoimmunity. So, biological therapeutics has been designed to interfere with the activation of T cells, as for example mAbs against CD4, CD5 and CD7 and this effect of mAbs on T cell surface receptors has been found to be therapeutically beneficial.

Conclusion

Although biological therapeutics has not been successful in completely suppressing autoimmune inflammation, promising research efforts are underway in this field. Several factors are responsible for this including the fact that big pharma companies are being increasingly stifled by generic drugs, the lack of new block buster molecules and the expiry of patent protection. As biological therapeutics have unlimited possibilities it offers scope for success in terms of research efforts that includes current research in studying pancreatic cancer using HT-RNAi and developing target specific functional antibodies; improving breast cancer therapies; and studying the genes linked to prostrate cancer. And the list of research possibilities in biological therapeutics is endless.

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