UPDATE 2-Dyax says FDA accepts genetic-disease drug response

* FDA sets Dec 1 as new target action date

* Says drug shows promise in second late-stage study

* Shares up as much as 22 pct (Adds analyst's comments, late-stage study details, updates share movement)

By Anand Basu

BANGALORE, June 8 (Reuters) - Biotechnology company Dyax Corp (DYAX.O) said U.S. health regulators accepted the complete response submission for its experimental treatment for a rare genetic disease and also announced positive data from a second late-stage study of the drug, sending its shares up 22 percent.

The company said the U.S. Food and Drug Administration has set Dec. 1 as a target action date to complete the review of the drug, ecallantide or DX-88.

Ecallantide is for the treatment of acute attacks of hereditary angioedema (HAE), a potentially life-threatening genetic disease characterized by painful swelling of the skin, intestine, mouth and throat.

In March, the FDA declined to approve the drug in the present form and sought additional data on the safe use of the drug. [ID:nBNG366348]

"We are confident that our proposed risk evaluation and mitigation strategy (REMS) for assuring the safe use of DX-88 and our response to other FDA requests thoroughly address the matters raised in the agency's letter," Chief Executive Gustav Christensen said in a statement.

The drug has a good chance of getting approved by the end of this year with a potential launch in the first quarter of 2010, given its strong efficacy data and assuming that the REMS program is acceptable, Wedbush PacGrow LifeSciences analyst Kimberly Lee said.

Last week, U.S. health regulators declined to approve competitor ViroPharma Inc's (VPHM.O) drug Cinryze for the same indication.

"I think they (Dyax) have a good chance of being first to market," said Lee, who has a "buy" rating and a $9 price target on Dyax shares.

Separately, Dyax said new data from a second late-stage trial showed that fewer patients who were treated with the drug experienced emerging HAE symptoms compared with those who were administered a dummy drug.

DX-88 is efficacious in treating all acute attack locations and was well tolerated, with no treatment-related serious adverse events, the company said.

Shares of the company touched a high of about $2.28 before paring some gains to trade up 9 percent at $2.04 on Monday, making them one of the top percentage gainers on Nasdaq.

For the alerts double-click [ID:nWNAB7423] . (Editing by Anil D'Silva and Deepak Kannan)