Ablynx developed its mini-antibodies following the discovery that camels and llamas (camelidae) possess fully functional antibodies that lack light chains. These heavy-chain antibodies contain a single variable domain (VHH) and two constant domains (CH2 and CH3). Importantly, the cloned and isolated VHH domain is a stable polypeptide with the full antigen-binding capacity of the original heavy-chain antibody. These heavy chain VHH domains form the basis of Ablynx's Nanobodies. Smaller versions antibodies have a number of advantages of their more traditional conterparts, including being cheaper and easier to manufacture, while retaining their selectivity and efficacy. They can also be administered in a variety of ways: injected, orally, in sprays or creams, as opposed to full size antibodies, which can only be delivered by injection. Dr Edwin Moses, CEO of Ablynx, refused to comment on how money the company hopes to raise through its initial public offering (IPO) on Euronext Brussels, but having already signed partnership deals that could be worth in excess of €1.5bn, it's unlikely to be small change by anyone's standards. Also, a rival company called Domantis, which also specialises in mini-antibodies as potential replacements for traditional antibody therapeutics, was bought by GlaxoSmithKline last December. The pharma giant paid £230m (€332m) for Domantis, and this could give an indication of the sort of money Ablynx will be hoping to raise. When GSK bought it, Domantis didn't have any drugs in clinical trials, although since then - in May - one of Domantis' licensees called Peptech started Phase I trials for PN0621. This drug targets tumour necrosis factor (TNF) to treat auto-immune inflammatory diseases such as rheumatoid arthritis. In this respect, Ablynx is slightly ahead of Domantis in that its lead drug candidate has now finished being dosed in Phase I trials, with the company expecting to announce the full results for ALX-0081 by the end of the year. The drug, dubbed a 'nanobody' targets von Willebrand Factor (vWF) to reduce the risk of thrombosis in patients with acute coronary syndrome.