Study Finds Excellent Outcomes for Intermediate Risk Prostate Cancer Patients Treated with Isoray’s Cesium-131

Mar 2, 2022

Study Finds Excellent Outcomes for Intermediate Risk
Prostate Cancer Patients Treated with Isoray’s Cesium-131

RICHLAND, WASHINGTON – March 2, 2022 – Investigators from the University of Pittsburgh
School of Medicine have published a clinical study that demonstrates excellent outcomes for localized intermediate-risk prostate cancer patients treated with Isoray’s Cesium-131 brachytherapy, commercially known as Cesium Blu.

The published article on the study, Treatment of intermediate-risk prostate cancer with Cs-131: Long-term results from a single institution, was authored by Joshua L. Rodríguez-López, MD, Ankur K. Patel, MD, Ronald M. Benoit, MD, Sushil Beriwal, MD, Ryan P. Smith, MD, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. The peer reviewed paper was published in the January-February 2022 issue of BRACHYTHERAPY, an international multidisciplinary journal of the American Brachytherapy Society. The study analyzed the outcomes for 335 intermediate-risk prostate cancer patients treated with Cesium-131 brachytherapy.

Study patients had significant follow-up time. The median follow-up was 5.8 years, with a range of 4 to 8.9 years. The study found both the “favorable” (147 patients) and “unfavorable” (188 patients) intermediate-risk groups demonstrated excellent biochemical outcomes. Those outcomes were 97.6% and 91.4% respectively at five years. For 135 “favorable” patients treated with Cesium-131 implant alone (excluding 12 patients who were treated with external beam radiation therapy and Cesium-131 implant), the outcome was 98.1%.

Intermediate-risk prostate cancer can be classified as “favorable” (FIR) or “unfavorable” (UIR). In localized prostate cancer, risk increases as PSA (prostate-specific antigen), tumor grade, and tumor stage advance, creating higher risk of treatment failure.

Study author Dr. Ryan P. Smith, MD, said, “The biggest thing we wanted to accomplish in analyzing this data was to try to individualize treatment because the intermediate risk group is the most heterogenous. We used Cesium-131 to decrease the duration of acute toxicity as compared to other radio isotopes because of its shorter half-life. For favorable patients, it is very clear that all you need is Cesium-131 prostate brachytherapy. For unfavorable patients, the combination of external beam radiation followed by Cesium-131 prostate brachytherapy allows us to avoid hormonal therapy for most patients.”

The study adds convincing data to the more than 14 years of accumulated experience with Cesium-131 prostate brachytherapy treatment and builds on the body of literature to support the use of this isotope.

Commenting on the study, Isoray CEO Lori Woods said, “We are very excited by the results of this study. We believe the import of these findings is significant. We further believe this study provides compelling evidence that strongly suggests patients diagnosed with intermediate-risk prostate cancer should be presented with Cesium-131 as a valuable treatment opportunity by clinicians.”

Isoray is a medical technology company and innovator in seed brachytherapy. The Company is the world’s only producer of Cesium-131 brachytherapy, which is powering expanding internal radiation treatment options throughout the body for prostate cancer as well as difficult to treat head and neck, brain, lung, gynecologic, pelvic, and colorectal cancers.

Contact
Media and Public Relations: Sharon Schultz (302) 539-3747
Investor Relations: Mark Levin (501) 255-1910

About Isoray
Isoray, Inc., through its subsidiary, Isoray Medical, Inc. is the sole producer of Cesium-131 brachytherapy seeds, commercially known as Cesium Blu, which are expanding brachytherapy options throughout the body. Learn more about this innovative Richland, Washington company and explore the many benefits and uses of Cesium-131 by visiting www.isoray.com. Follow us on LinkedIn and Twitter. Join us on Facebook.

Safe Harbor Statement
Statements in this news release about Isoray’s future expectations, including: efficacy of the biochemical success rate for 4 and 9 year results with or without external beam radiation, the advantages of our products and their delivery systems, whether additional studies are released that support the conclusions of the study discussed in this news release, whether interest in and use of our products will increase or continue, and all other statements in this release, other than historical facts, are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 (“PSLRA”). This statement is included for the express purpose of availing Isoray, Inc. of the protections of the safe harbor provisions of the PSLRA. It is important to note that actual results and ultimate corporate actions could differ materially from those in such forward-looking statements based on such factors as physician acceptance, training and use of our products, our ability to successfully manufacture, market and sell our products, our ability to manufacture our products in sufficient quantities to meet demand within required delivery time periods while meeting our quality control standards, our ability to enforce our intellectual property rights, whether additional studies are released that support the conclusions of past studies, whether ongoing patient results with our products are favorable and in line with the conclusions of clinical studies and initial patient results, patient results achieved when our products are used for the treatment of cancers and malignant diseases, successful completion of future research and development activities, whether we, our distributors and our customers will successfully obtain and maintain all required regulatory approvals and licenses to market, sell and use our products in its various forms, continued compliance with ISO standards, the success of our sales and marketing efforts, changes in reimbursement rates, the procedures and regulatory requirements mandated by the FDA for 510(k) approval and reimbursement codes, changes in laws and regulations applicable to our products, the scheduling of physicians who either delay or do not schedule patients in periods anticipated, the use of competitors’ products in lieu of our products, less favorable reimbursement rates than anticipated for each of our products, and other risks detailed from time to time in Isoray’s reports filed with the SEC. Unless required to do so by law, we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.