Shares in Dyax Corp has soared after the US firm announced that it expects to file for approval for its hereditary angioedema treatment DX-88 at the beginning of the fourth quarter.

The filing will be based on data from a Phase III trial which showed that DX-88 (ecallantide) met its primary and secondary endpoints in patients with HAE, a rare genetic disease characterised by episodes of acute swelling, pain and inflammation. The EDEMA4 study involved 96 patients who were assigned either DX-88, an injectable recombinant small protein, or placebo.

The data revealed that 93.8% of patients on ecallantide reported a successful response at four hours, compared with 58.3% in the placebo group. 43.8% on the Dyax maintained significant improvement in overall response for 24 hours, compared to 20.8%.

William Pullman, chief development officer at Dyax, said that the positive results from EDEMA4 and an earlier study – EDEMA3 – “support the potential of DX-88 as an important acute therapy for HAE”. The firm’s chief executive Henry Blair added that the firm’s proposed Biologics License Application to the US Food and Drug Administration “will include the most extensive placebo-controlled assessment of any therapy for the treatment of HAE”.

A number of other drug candidates have entered the HAE arena of late. The UK’s Shire is in the process of acquiring the German biotechnology Jerini and its HAE drug Firazyr (icatibant) which has just been given the green light by regulators in Europe. Also the HAE drug Cinryze (C1 inhibitor [human]) is the principal reason behind ViroPharma’s proposed takeover of fellow USA-based form Lev Pharmaceuticals.