By Randall Osborne

Just over six months after the company raised $16 million through a partnership to develop its edema drug, CV Therapeutics Inc. said a Phase II clinical study with CVT-124 showed statistically significant positive results.

CV Therapeutics, of Palo Alto, Calif., is developing CVT-124, a highly selective adenosine receptor antagonist, to treat edema associated with congestive heart failure.

In March, Biogen Inc., of Cambridge, Mass., agreed to pay CV Therapeutics $16 million for exclusive worldwide rights to develop and sell CVT-124. In the deal, CV Therapeutics received up-front payments and will be paid milestones and royalties. (See BioWorld Today, March 11, 1997, p. 1.)

When heart failure causes reduced pumping action by the heart, less blood flows through the kidney, which increases the retention of salt and water (edema) in order to maintain blood pressure. The Phase II clinical study of CVT-124 showed the drug increased the excretion of sodium and chloride in urine. At the same time, the 18 patients studied showed minimal loss of potassium, which is a potentially dangerous side effect of diuretics currently used to treat edema related to congestive heart failure.

Losing potassium, heart patients "can have dangerous arrhythmias," said Louis Lange, chairman and CEO of CV Therapeutics. "They can even die from it."

In milder cases, they must replace the potassium with supplements that "taste terrible," Lange said. "Patients hate them."

Most important, CVT-124 worked at the proximal tubule area of the kidney, where salt and water absorption become the greatest as congestive heart failure grows worse, Lange said. The drug "shifts into the power alley, if you will, during progression [of congestive heart failure]," he said. "We've never had a good proximal diuretic."

CVT-124 was well tolerated by patients in the Phase II study, with no effects on blood pressure, heart rate, electrocardiogram findings or other laboratory tests. CV Therapeutics and Biogen will conduct more Phase II clinical trials to gauge the effects of varying doses and further characterize the drug, which has been evaluated in more than 60 U.S. subjects.

CV Therapeutics conducted the Phase II clinical study, and now Biogen will take over, Lange said. "It's going to be a broad and deep program," but protocol has not yet been finalized. Data from the new Phase II trials should be available by late next year, Lange said.

CV Therapeutics' stock (NASDAQ:CVTX) closed Thursday at $11.125, down $0.88. Biogen (NASDAQ:BGEN) ended the day at $32.813, down $0.06. *