Inflammation franchiseBackgroundInflammation is a natural response of the body to injury, disease or irritation and is often associated with redness, swelling and pain. These changes are part of the natural inflammatory response that protects the body against invasion by foreign materials.Inflammatory diseases occur when the body’s immune system attacks its own tissue and causes damage. Two major inflammatory diseases are rheumatoid arthritis (RA) and Crohn’s disease. In rheumatoid arthritis, the immune system usually attacks proteins in the hands, wrists, knees and feet that are mistakenly identified as ‘foreign’. Rheumatoid arthritis affects roughly one person in 100, tends to run in families and is three times more likely to occur in women than men. Tumour Necrosis Factor alpha (TNF  ) is a protein produced by white blood cells that when over-produced, contributes to inflammatory diseases.TNF is the target of Arana’s lead anti-inflammatory compound ART621, because it occurs early in the inflammatory process and triggers a cascade effect, causing the release of many different inflammatory molecules. ART621 - entering Phase IIART621 is a new type of therapeutic antibody called a domain antibody.A number of anti-TNF products (Humira®, Remicade® and Enbrel®) are currently on the market for the treatment of rheumatoid arthritis. Unlike previous treatments, such as aspirin, that deal with the signs and symptoms, the anti-TNF products prevent further progression of the disease. Global sales for these products totalled about US$10.8 billion in 2006 and are projected to rise to about twice that in 2012. However, new antibody-based treatments are still needed because some patients have developed resistance and many stop responding to a particular anti-TNF antibody after pro-longed use, yet respond when switched to a different one. ART621 is the first human framework domain antibody (dAb) to be used in human trials. Domain antibodies exhibit the binding properties to a target characteristic of a full-sized antibody, but are considerably smaller. This has the potential to make them effective in the treatment of inflammation, as they may have advantages in entry into diseased joints and tissues. In addition, its smaller size means ART621 can be readily manufactured at high levels and purified at high yield, which is favourable to cost effective manufacture. In animal models of rheumatoid arthritis, ART621 matched the performance of one blockbuster anti-TNF antibody product currently on the market and displayed favourable properties in terms of stability, duration of action and tissue localisation within the body. In October 2007, ART621 completed a Phase I clinical trial of escalating doses in 30 healthy volunteers. In the trial, at St Vincent’s Hospital in Sydney, single doses of ART621 administered intravenously and under the skin, were well tolerated and free of side effects. Data from the Phase I clinical trial results and additional animal studies will inform the design of a longer, more involved Phase II study scheduled for 2008, which will assess whether ART621 is effective in the treatment of inflammatory disease. PMX53 - in pre-clinical developmentPMX53 is a small cyclic peptide (a short amino-acid chain) currently in pre-clinical development for the treatment of inflammatory diseases. PMX53 targets a different protein to TNF in the inflammatory response pathway.
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