US biotech Dyax saw its stock rocket as much as 55% Wednesday in a flurry of excitement over extremely positive early-stage test results for its experimental angioedema drug.

Hereditary angioedema (HAE) is a rare and potentially fatal blood disorder characterised by painful swelling that can affect the face, hands, feet, digestive system and respiratory system.

A Phase Ib trial of Dyax’ DX-2930 found that there were no attacks of HAE in patients given the 300mg dose, while attacks were reduced by 88% in those treated with 400mg. The drug was also well-tolerated at both doses.

Commenting on the results, RBC Capital Markets analyst Michael Yee reportedly noted that they were “well above consensus expectations” and questioned whether Dyax has managed to find a cure for the condition. 

The firm also said it has received Fast Track designation from the US Food and Drug Administration for the investigation of DX-2930 for HAE, speeding up the regulatory process.