American Society of Breast Surgeons to Lead MammoSite RTS Patient Registry; Data From MammoSite Patient Registry Used to Assess Long-Term Patient Progress.

Business Editors/Health/Medical Writers

ALPHARETTA, Ga.--(BUSINESS WIRE)--Feb. 11, 2004

Proxima Therapeutics, Inc. today announced that the American Society of Breast Surgeons will manage the MammoSite Radiation Therapy System (RTS) Patient Registry. The Registry is a national prospective data collection program designed to report on the results achieved in the clinical setting in order to monitor the long-term outcomes of patients treated with MammoSite, a targeted method of partial breast irradiation for treatment of breast cancer. With more than 1,600 members, the American Society of Breast Surgeons is the largest surgical society of physicians dedicated exclusively to improving treatments for breast disease. This important scientific initiative will contribute expert retrospective analysis to the growing clinical database on MammoSite to define further the appropriate patient population for this treatment.

The registry currently includes information on over 800 of the patients treated with MammoSite since its FDA clearance in May 2002 and the society aims to enroll a total of 1,300 patients. The society will compile, assess and review information from breast cancer patients treated with this internal, five-day treatment under the supervision of Dr. Peter Beitsch, director of the Dallas Breast Center and a member of the American Society of Breast Surgeons research committee, and Dr. Frank Vicini, radiation oncologist at William Beaumont Hospital in Detroit and the most widely published scientist in partial breast irradiation. Dr. Vicini led a five-year follow-up study published in the Journal of the National Cancer Institute (August 2003) which found that partial breast irradiation produces comparable results to whole-breast radiation therapy in preventing breast cancer recurrence in women with early-stage breast cancer treated with breast-conserving therapy.

MammoSite has been used to treat thousands of women in the United States. Doctors at hundreds of U.S. hospitals and radiation treatment facilities offer MammoSite to appropriate, early-stage patients, affording them with a targeted internal treatment delivered in five days. The MammoSite device is a balloon catheter that is placed in the cavity created by a lumpectomy. During a five-day course of therapy, a tiny radioactive seed attached to a wire is inserted into the balloon, delivering prescribed levels of radiation under precise computer control to the targeted tissue surrounding the cavity. No source of radiation remains in the patient's body between treatments or after the final procedure.

"The wide adoption of MammoSite provides us with an opportunity to lend our expertise to the study of this most widely used form of partial breast irradiation. By tracking MammoSite patients, we intend to provide our members with data in order to make informed recommendations to their patients," said Dr. Richard Fine, president of the American Society of Breast Surgeons. "Proxima and the society agree that patients should be followed closely to ensure responsible application of this technology. At this point the society can build upon the registry, using our surgical expertise to analyze the patient data."

"The American Society of Breast Surgeons is a strong organization based on principles we support--the study of breast surgery, research, improved standards of practice and the exchange of ideas. Based on successful clinical experience with MammoSite to date, we look forward to gaining new insight from the society and their expert assessment of the clinical outcomes and refinement of surgical techniques," said Timothy J. Patrick, president and chief executive officer of Proxima Therapeutics, Inc.

About the American Society of Breast Surgeons

The American Society of Breast Surgeons was formed to encourage the study of breast surgery, to promote research and development of advanced surgery techniques, to improve standards of practice for breast surgery in the United States, and serve as a forum for the exchange of ideas.

About MammoSite RTS

MammoSite RTS delivers radiation over a five day course of therapy only to the area directly surrounding the tumor site. Since FDA clearance in May 2002, thousands of patients have been treated at the hundreds of centers across the nation offering this form of partial breast irradiation.

Safety and performance of the device for delivery of internal radiation were evaluated in a multi-center study, which involved women with early-stage breast cancer. The results of the study were recently published in the International Journal of Radiation Oncology*Biology*Physics (February 2003).

About Proxima Therapeutics

Based in Alpharetta, Ga., Proxima Therapeutics, Inc. is a privately held medical device company established in 1995 to develop site-specific cancer treatment systems for breast and brain tumors. Products include GliaSite RTS for brain cancer and MammoSite RTS for breast cancer. Additional information is available on the company's Web site at www.mammosite.com. Physicians and patients may call 1-86-MAMMOSITE (1-866-266-6748) for more information.