Dyax Corp.'s stock received some initial bounce on Phase I and Phase II trial news for DX-88, its recombinant small protein.

The stock settled over the course of the day, but most investors viewed the data as a positive harbinger for the firm's expected Phase III trial in hereditary angioedema (HAE).

Shares (NASDAQ:DYAX) fell 5 cents Thursday, to close at $4.71 after trading as high as $4.97.

The Phase I trial, involving 17 healthy volunteers, was designed to compare the relative bioavailability of intravenous and subcutaneous (SQ) administration of 10-mg and 30-mg doses of DX-88. Top-line results showed bioavailability was equivalent for both methods of administration.

Based on that finding, Dyax has begun converting HAE patients in the ongoing EDEMA2 trial from IV dosing to the subcutaneous version of DX-88, which should help Dyax get patient data with SQ DX-88 before the company starts its pivotal Phase III trial, planned for later this year.

Dyax, of Cambridge, Mass., presented Thursday at the World Allergy Congress in Munich, Germany, positive interim results from EDEMA2 in the first 120 attacks of HAE treated with intravenously administered DX-88. The trial is testing the drug when given multiple times to patients for separate HAE attacks, and first data show that DX-88 can provide therapeutic benefit, with no apparent decrease in drug effect in patients exposed to multiple doses.

In the analysis, 120 HAE attacks were observed in 47 patients treated with IV DX-88. The results confirm earlier analysis, the company said, which indicated that the drug is well tolerated and can relieve HAE symptoms regardless of the number of and/or type of attack, across patient demographics.

Thomas Beck, Dyax's executive vice president, business and product development, said the data and the conversion to SQ dosing in EDEMA2 set "a clear course for initiation of our pivotal Phase III trial." If all goes well, Dyax expects to begin filing a biologics license application in HAE in 2006, and the firm hopes for approvals in the U.S. and EU in 2007.

The drug is being developed in a joint venture with Genzyme Corp., also of Cambridge, for the treatment of HAE, which is characterized by attacks of peripheral, abdominal and/or laryngeal pain and swelling.

Jennifer Chao, of Deutsche Bank, wrote in a research note that her firm expects "rapid enrollment of the Phase III study." She estimated a $300 million market for the drug.

Genzyme's stock (NASDAQ:GENZ) dropped 80 cents to close at $60.09.