By Mary Welch

Diatide Inc. signed a license agreement with Angstrom Pharmaceuticals Inc. to develop diagnostic and therapeutic radiopharmaceuticals for cancer.

Under an associated license agreement, San Diego-based Angstrom granted Diatide worldwide exclusive rights to imaging and certain therapeutic products developed from its proprietary tumor-targeting technology. Diatide, based in Londonderry, N.H., will make a ¿substantial¿ up-front payment and will make future research and milestone payments plus royalties on product sales.

¿The deal is good for them, and it¿s good for us,¿ said Richard Dean, president and CEO of Diatide.

The collaboration is the ¿biggest one for us,¿ said Terence Jones, chairman and CEO of Angstrom. ¿It really is our first deal but we¿ll be making several announcements in the coming weeks. We¿re just coming onto the scene. We¿ve been quiet.¿

Diatide will provide research support and take any products through clinical trials and regulatory approval. The companies expect to file an investigational new drug application on a cancer imaging agent in 2000.

Receptor Triggers Angiogenesis, Metastasis

A private company founded in 1996, Angstrom has developed proprietary small cyclic peptides that bind tightly and specifically to the urokinase plasminogen activator receptor (uPAR), a key receptor found in virtually all solid tumors, including breast, prostate, colon and lung. The molecule orchestrates the complex mechanisms involved in tumor angiogenesis and tumor metastasis. UPAR is found in tumors and is rarely found in healthy people.

¿We¿ve identified the key receptor that switches on a cascade of events that trigger angiogenesis and metastasis,¿ Jones said. ¿If we can block the uPAR, then its receptor is switched off and these cascades of events are stopped.¿

¿Because the uPAR is a specific biological marker, we can target it with an imaging agent and determine if a patient would benefit from a therapy agent, and then follow up and determine the effectiveness of the therap,¿ Dean said. ¿It¿s a find it, fight it, and follow it up strategy ¿ all with the same targeting piece.¿

In addition to being present on tumor cells, uPAR also is on several tumor-associated cell types, particularly angiogenic endothelial cells. This means that targeting uPAR with a radiotherapeutic agent may have potent anti-angiogenic effects, in addition to direct anti-tumor effects.

¿What happens is that after you target the large tumor, little cells fall off and create problems down the line,¿ Dean explained. ¿There is an opportunity here to wipe out these guys and prevent the spreading of the disease and get long-term remission.¿

Jones believes the chemotherapy cancer treatment market segment, now estimated at about $10 billion, will reach $100 billion by 2020. ¿It is set to expand inordinately and we¿re going to get in the game. The question is whether a patient would prefer nasty chemotherapy to a safe, non-toxic therapy.¿

Diatide plans to develop an imaging product similar to NeoTect, its scintigraphic imaging product for suspected malignant lung tumors. NeoTect is a small synthetic peptide combined with technetium-99m. When a patient is suspected of having lung cancer, an X-ray or computed tomography scan is usually taken, which can detect only if a mass ¿ or tumor ¿ is present, not if it¿s malignant.

The next step is usually a biopsy or open-chest surgery. With NeoTect, when the peptide is injected, it attaches itself to the somatostatin receptor on cancer cells. Two hours later, the patient is scanned with a gamma camera, which can pick up the gamma signal emitted by the technetium and a malignancy can be detected. Diatide received an approvable letter from the FDA in December and expects final approval this summer. (See BioWorld Today, Dec. 18, 1998, p. 1.)

¿This approach with uPAR is similar to the approach with NeoTect but we¿re looking to have a broader application for solid tumors,¿ Dean said.

Diatide¿s stock (NASDAQ:DITI) closed Thursday at $5, down $0.063. n

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