UPDATE 1-United Therapeutics' Viveta meets main goal, shrs soar

(Adds details, company and analyst comments, updates share movement)

By Niveditha Ravi and Jennifer Robin Raj

BANGALORE, Nov 1 (Reuters) - United Therapeutics Corp (UTHR.O) said its drug to treat a life-threatening lung disease met its main goal of improving exercising capacity in a late-stage trial, sending shares up more than 40 percent to their seven-year high.

The drug Viveta is an inhaled formula of treprostinil to treat pulmonary arterial hypertension (PAH), a rare condition causing heart failure due to high blood pressure in the arteries of the lungs.

The Silver Spring, Maryland-based company expects to submit a new drug application for Viveta sometime in the middle of 2008, a company spokesman Andrew Fisher said by phone.

In the trial, patients received Viveta in combination with either Tracleer or Revatio. Swiss biotech Actelion Ltd's (ATLN.VX) Tracleer and Pfizer Inc's (PFE.N) Revatio, a version of Viagra, are both approved for treating PAH.

The main goal of the study was to show a significant improvement in the capacity to exercise, which is a measure commonly used to determine effectiveness of PAH drugs by the U.S. Food and Drug Administration, Fisher said.

Prior to the trial, patients were measured on how far they walk in six minutes and investigators took measurements again at the end of the study to determine if patients had walked any further, he added.

Patients on Viveta showed a significant 20-meter improvement in a six-minute walk distance (6MWD), compared to those on the dummy drug.

"The 20-meter improvement in 6MWD is robust enough to be sufficient for filing to regulatory agencies on the basis of this trial alone and in our view removes clinical risk," JP Morgan analyst Geoffrey Meacham said in a note to clients.

The company already markets an infused form of treprostinil under the brand name Remodulin, which is given to patients intravenously or subcutaneously to treat PAH.

Meacham, who retained his "overweight" rating on the stock, said third-quarter Remodulin sales of $57 million beat his estimate of $50 million.

Viveta, however, did not prove to be more effective than the dummy drug in certain secondary trial goals. Analysis of two remaining secondary goals is ongoing, the company added.

United Therapeutics shares rose as much as 40.8 percent to $96.34 in early trade. The shares later fell back to trade up more than 30 percent at $89.52 in afternoon trade on the Nasdaq.