BioCryst Pharmaceuticals (Nasdaq: BCRX) said in May that it planned to take an experimental drug treating the rare disease hereditary angiodema into Phase II clinical trials later this year. But news disclosed Monday that the compound preformed well in a Phase I trial triggered an explosion of buying on Wall Street.

Buyers swapped more than 15.4 million shares in a day of frenzied buying – more than 10 times the daily average of 1.15 million.

Shares had closed Friday at $2.46 but skyrocketed as high as $3.80 before closing the day up 51.2 percent at $3.72.

The company’s market cap surged to nearly $198 million.

The Durham drug developer does not yet have any Food and Administration-approved drugs,.

Hereditary angiodema is a rare genetic condition that results in swelling in the face and airways and can lead to suffocation. The company said that the compound BCX4161 is progressing and should be completed this summer.

“We are very pleased that this first-in-human trial of BCX4161 met all of its objectives. The safety, tolerability, level and consistency of drug exposure and kallikrein inhibition achieved significantly increases our confidence to move this program forward,” said Dr. William P. Sheridan, Chief Medical Officer at BioCryst, in a statement. “We look forward to conducting a Phase II proof of concept study later this year to evaluate BCX4161’s ability to reduce the frequency of edema attacks in HAE patients.”