Diatide filing takes precedence in peptide-labeling patent case

PTO initiates patent interference proceeding

Radiopharmaceutical developer Diatide of Londonderry, NH, reported last month that the U.S. Patent and Trademark Office has announced an interference between a Diatide patent application and a patent of another company, Palatin Technologies subsidiary RhoMed. The PTO's declaration of interference is the initial step in the process of identifying the first inventor of a product when two or more patent applications claim the same invention.

Diatide believes its peptide-labeling patent application, filed in 1994, takes precedence over RhoMed's. Diatide's application covers its primary product, AcuTect, a kit for nuclear medicine imaging of acute venous thrombosis that was cleared by the Food and Drug Administration in September (SCAN 9/30/98). The PTO's announcement names Diatide as the senior party in the interference.

Palatin is also developing technetium-based products, such as its infection imaging agent, LeuTech. The Princeton, NJ-based firm received a patent in 1997 for its method of radiolabeling a particular type of peptide, a method invented by RhoMed, which Palatin acquired in 1996. The patent covers an invention that Palatin does not intend to develop commercially at this time.

In other Diatide news, the company received bad news in December on the status of its European regulatory submission for AcuTect. On Dec. 10, Diatide and its marketing partner, Nycomed Amersham of Buckinghamshire, U.K., withdrew the product's marketing authorization application (MAA) to the European Medicines Evaluation Agency (EMEA).

The companies withdrew the application after the EMEA raised several questions about the reliability of evaluating AcuTect's efficacy by comparing it to contrast venography. Diatide and Nycomed Amersham said they plan to obtain information to meet the agency's requirements.

On the positive side, Nycomed Amersham in November submitted an MAA for NeoTect, a peptide-based radiopharmaceutical for imaging malignant lung tumors. The EMEA has accepted the application as valid, and NeoTect could be reviewed and approved within 12 to 18 months.

As for NeoTect's status in the U.S., Diatide announced on Dec. 17 that it has received an approvable letter from the FDA. The agent was given priority review at the FDA, and final approval could be granted once the company clarifies details and agrees to postapproval requirements. Nycomed Amersham has U.S. rights to sell NeoTect (formerly P829).