Theseus Imaging Achieves Technical Milestone in Imaging Apoptosis Associated with Cardiac Transplant Rejection.

Business Editors

CHATSWORTH, Calif.--(BUSINESS WIRE)--Jan. 13, 2000

North American Scientific Inc. (Nasdaq:NASI) and Theseus Imaging Corp. announced today that Theseus has achieved a significant technical milestone in clinical studies of its Apomate(TM) Kit for use in imaging apoptosis associated with organ transplant rejection.

The technical milestone was the successful correlation of noninvasive imaging of apoptosis with biopsy-proven cardiac transplant rejection using Theseus' Apomate(TM) Kit for the preparation of Technetium Tc-99m recombinant human Annexin V.

Nuclear medicine images obtained using routine instrumentation available in over 3,500 U.S. hospitals clearly demonstrated localization of the imaging agent in patients with transplant rejection. In current clinical practice, obtaining such information requires repeated cardiac catheterization and endomyocardial biopsy.

Each patient receiving a cardiac transplant may undergo up to 15 catheterization procedures in the first year after transplant in order to assess the adequacy of immunosuppression medication required to prevent rejection of the new heart. Apomate(TM) is intended to provide equivalent information through a noninvasive imaging procedure using a new technique involving molecular imaging of the biochemical changes associated with rejection.

The demonstration of imaging of cardiac transplant rejection in patients provides proof of principle for the concept of Apoptosis imaging developed in preclinical studies by Drs. H. William Strauss and Francis Blankenberg of Stanford University, Dr. Jonathan Tait of the University of Washington and their colleagues. Theseus has licensed the apoptosis imaging technology from those institutions.

"The ability to image apoptosis in patients would provide physicians with an important new tool for managing the treatment of disorders involving programmed cell death, such as transplant rejection," said Dr. Allan Green, president of Theseus Imaging.

"The availability of a noninvasive imaging study which could replace multiple catheterization procedures and allow more timely assessment of the adequacy of patient medication would benefit the patients and markedly reduce treatment costs, while maintaining the current good outcomes associated with cardiac transplant."

North American Scientific and Theseus Imaging announced the signing of a definitive merger agreement on Oct. 21, 1999. The acquisition of Theseus is contingent upon final due diligence, receipt of a financial fairness opinion from a qualified independent third party and satisfactory initial clinical results.

Theseus Imaging is a development-stage company involved in the identification and development of radiopharmaceutical products for in vivo medical imaging in collaboration with university researchers worldwide.

North American Scientific manufactures and markets a broad line of products for medical therapeutic and diagnostic, environmental and research applications. The company is currently the only manufacturer of both types of FDA-approved radioactive seeds, Iodine-125 and Palladium-103, for the treatment of prostate cancer and certain other diseases. For more information, visit the company's Web site at www.nasi.net.

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