The results showed that the antibodies were biologically active and reduce the number of eosinophils, a class of white blood cells, which are implicated as a major cause of asthma. The results were presented at the International Eosinophil Society 5th Biennial Symposium, held in Snowbird, Utah, US, at the end of last week. The cells, which also combat parasitic infection, express the interleukin-5 (IL-5) receptor and are believed to differentiate in bone marrow in response to the cytokines IL-5 and IL-3. These cells circulate in the blood and migrate to inflammatory sites such as those caused during allergic responses. Asthma is a disease of the airways that causes wheezing, breathlessness chest tightness and coughing and leads to around 180,000 deaths a year worldwide. The US National Institutes of Health (NIH) have estimated that healthcare costs for asthma total approximately $14bn a year in the US alone. The MEDI-563 MAb, originally called BIW-8405 during its early stage development by BioWa, has been developed in an effort to reverse the debilitating effects of asthma by eliminating the eosiniphils that accumulate in the lung. Not only does the antibody kill cells expressing the IL-5 receptor, but it also inhibits the interaction of IL-5 with the cells. Preclinical research has suggested that depletion of eosininophils by IL-5 inhibition may result in reduced airway inflammation, airway hyper-responsiveness and mucous secretion. "The initial data from this trial suggest that our efforts to not only inhibit the cytokine involved in eosinophil production, but to actually directly deplete eosinophils, may offer a viable therapeutic approach to developing new treatments for patients with asthma," said Dr Barbara White, MedImmune's vice president of clinical development, inflammatory disease. Previous attempts to develop IL-5 targeted therapies have lacked efficacy due to incomplete eosinophil depletion in lung tissue. The MEDI-563 antibody has been developed to contain no fucose in its sugar (glycol) groups using BioWa's Potellignet technology to enhance its ability to bind to the antigen and increase its antibody-dependant cellular cytoxicity (ADCC). The increased eosinophil depletion exhibited by MEDI-563 has been attributed to its enhanced ADCC profile. MEDI-563 exhibits greater activity because it has been developed using BioWa's Potelligent technology platform to yield antibody with no fucose in its sugar (glycol) groups to enhance their ability to bind to the antigen and increase ADCC. The two companies entered into a licensing and collaboration agreement to develop and commercialise new inflammatory disease therapies that target IL-5 in December 2006. Since then, MedImmune has been acquired by AstraZeneca in a deal worth $15.6bn that closed on 18 June, 2007.