The FDA informed Medco Research Inc. its new drug application (NDA) for ViaScint, a radiopharmaceutical product designed to assess myocardial viability, is not approvable and additional work will be needed.

Medco, of Research Triangle Park, N.C., and its licensing partner, Nordion International, of Kanato, Ontario, plan to meet with the FDA in the next several weeks to determine the requirements for obtaining marketing clearance for the product.

Glenn Andrews, chief financial officer at Medco, told BioWorld Today the issues and opinions of the FDA came as a "complete and total surprise."

"The company had worked closely with the FDA through the development program," Andrews said, "and in the opinion of the nuclear cardiology consultants we have had on the project, the data submitted were sufficiently convincing."

Andrews added that after the NDA submission, an investigator looking at the product retired and a new investigator was put on the case. "After that the communications really ceased," Andrews said.

"Until we meet with the FDA, we really can't address the reasons for this disconnect, or what additional work is needed to clear the product for marketing," he added. "We thought everything was going along all right."

Regardless of its review status, ViaScint, Andrews said, will be partnered out or returned to Nordion, with Medco retaining its rights as provided in the original licensing agreement.

Andrews said the company is in the process of refocusing its resources on its core business: adenosine-based technologies, which Medco believes will have "far more valuable opportunities in that field."

Medco has two adenosine products marketed for cardiovascular indications: Adenocard for the treatment of paroxysmal supraventricular tachycardia, and Adenoscan, which is an adjunct to thallium cardiac imaging.

The company's stock (AMEX:MRE) closed Friday at $11.125, down $1.25. — Frances Bishopp