Diatide gets nod for AcuTect agent for detecting acute venous thrombosis

Nycomed Amersham retains rights to radiotracer

Coming to market with a product that satisfies an unmet need and has no close competition is the dream of most medical technology companies. Radiopharmaceutical developer Diatide of Londonderry, NH, bets it will realize that dream with the receipt this month of Food and Drug Administration market clearance of the company’s first peptide-based nuclear imaging agent, AcuTect, for use in imaging acute venous thrombosis.

Technetium-labeled AcuTect moved relatively swiftly through the FDA because it received priority review status, said Diatide president and CEO Richard Dean. AcuTect’s new drug application was submitted to the U.S. regulatory agency in August of last year.

“It is rare these days, but U.S. (clearance) came before the European,” he told SCAN.

The FDA expedited review of AcuTect because the agent showed promise in differentiating acute from chronic blood clots in the lower leg, Dean said. No imaging technique can currently make this distinction, which is essential in plotting therapeutic strategy. Acute clots are the most likely to break off and cause pulmonary embolisms.

The key to AcuTect’s diagnostic power is the use of a peptide—amino acids joined by a peptide bond—targeted at the glycoprotein IIb/IIIa receptor on the surface of activated platelets, he said. These platelets are an indicator of acute clots.

AcuTect has an advantage over competing peptide technology provided by Mallinckrodt of St. Louis in that it is labeled with technetium-99m, Dean said. Mallinckrodt’s OctreoScan agent, for neuroendocrine tumors, is labeled with indium.

“The real challenge is getting technetium on to the molecules,” he said. “Technetium is the most widely available (imaging radioisotope). It is the least expensive, gives the cleanest images, and is the safest.”

The current diagnostic standard for identifying clots in the leg is ultrasound. But follow-up procedures are required in the 10% to 27% of cases where ultrasound is equivocal, Dean said. Prior to AcuTect, further testing could be done either through contrast venography or additional ultrasound scanning, which involves bringing the patient back repeatedly.

Venography is declining in use because it is a difficult and painful procedure, Dean said. It involves the injection of radiographic contrast, often through multiple punctures, into small veins in the foot. AcuTect, on the other hand, requires a less-invasive intravenous injection in the arm. Diatide hopes its nuclear agent will step in and replace contrast venography as the back-up test to ultrasound.

The nuclear medicine procedure will cost about $800, which is several hundred dollars more than ultrasound. AcuTect’s unique ability to distinguish acute clots, however, should maintain demand, he said.

Although partner Nycomed Amersham of Buckinghamshire, U.K., recently decided to step back from support of future Diatide research (SCAN 8/19/98), the two companies continue to work closely on the commercialization of AcuTect. They also collaborate on the second product in Diatide’s pipeline, NeoTect, which is targeted at lung cancer, Dean said.

The two firms will co-promote AcuTect in the U.S. Nycomed Amersham will target sales of AcuTect into the radiology, vascular surgery, emergency, and oncology departments of hospitals, he said. Diatide will work with radiopharmacy firms in distributing the agent. Profits will be split evenly after deducting the cost of goods and promotion.

Diatide contracts out the manufacturing of its agents. Rentschler Biotechnology of Germany produces the finished dosages of AcuTect, Dean said. While Nycomed Amersham has exclusive rights to the agent in Europe and select markets in Africa and the Middle East, Diatide is still in negotiations for rights to sell AcuTect in the Asia/Pacific region, he said.