Response Oncology Reports Promising Clinical Results from Its High Dose Chemotherapy Breast Cancer Protocol.

Business Editors & Health/Medical Writers

MEMPHIS, Tenn.--(BUSINESS WIRE)--July 12, 2000

Five Year Survival Rate Estimates of 71% in High Dose

Chemotherapy Outcomes Data on 540 Patients with High-Risk Breast

Cancer

Response Oncology, Inc. (NASDAQ NMS: ROIX) today announced the promising outcomes from its high dose chemotherapy protocol in the treatment of adjuvant breast cancer. The outcomes data were collected and analyzed from 540 patients with high risk (Stage II/III) breast cancer. These outcomes were reported earlier at the International Bone Marrow Transplant Registry Meeting in Anaheim CA, March 25-28, 2000. Based upon on a median follow-up of 55 months, there was an estimated five-year overall survival rate of 71% in these patients. This compares with an estimated five-year overall survival rate of approximately 60% from a previously published, federally-funded Cancer and Leukemia Group B (CALGB) study of similar patients having received standard chemotherapy only.

The results reported today were drawn from a total of 540 patients with high-risk breast cancer, which was defined as Stage II/III disease with extension to axillary lymph nodes. The median number of involved lymph nodes was ten, in addition to the primary breast tumor. The first patient was treated in 1990. The participants were treated with the STAMP V regimen, which included high dose cyclophosphamide, thiotepa and carboplatin (CTCb), and received peripheral blood stem cell support. At a median follow up of 55 months, 398 women were alive and 347 survived event free. The Kaplan-Meier estimates of overall survival and event free survival at five years were 71% and 62%, respectively. There were two treatment-related deaths (less than 1%).

The results also demonstrated that known prognostic factors, such as disease stage, number of positive lymph nodes, hormone receptor status and differentiation, were associated with the estimated survival rates. Groups of patients with fewer risk factors showed statistically improved survival rates. The differences between previous trials of high dose chemotherapy for high risk breast cancer, including the relatively high-profile studies reported at the Annual Meeting of the American Society of Clinical Oncology in 1999, may be explained by both the relatively short length of follow-up and variations in these risk factors.

In commenting on these results, I. Ann Sysel, M.D., Response Oncology's vice president of medical services, said, "We were very pleased with these results. Our patient survival estimates are encouraging in this high-risk patient population undergoing high dose chemotherapy. We were equally pleased to confirm the association between the number of risk factors and survival rates in this group of women undergoing high dose chemotherapy."

Risk factor, subset analysis and randomized phase III clinical trials will provide better insight into the role of high dose chemotherapy in the treatment of breast cancer and the importance of appropriate patient selection. The data presented today are a case series, in contrast to the randomized phase III study reported by Dr. Rodenhuis from the Netherlands at ASCO 2000. Dr. Rodenhuis reported on 885 patients with high-risk breast cancer, randomized to receive five cycles of chemotherapy or four cycles of chemotherapy plus high dose chemotherapy and auto-transplant. Preliminary data on the first 289 patients favors the high dose arm; with a 3-year median follow-up, the relapse free survival was 77% in the high dose group, compared to 62% in the standard dose arm. Overall survival was 79% on the standard arm and 89% on the high dose arm. There were four (1%) early-treatment related deaths on the high dose arm and one on the standard dose arm. While this is preliminary information, we believe this study supports the continued evaluation of high dose chemotherapy in patients with high-risk breast cancer. Response Oncology has two clinical studies in the development phase for this patient population. One study will evaluate the impact of adding maintenance therapy following recovery from high dose chemotherapy and auto-transplant. The second study will be in cooperation with a consortium of breast cancer investigators outside the Response Oncology network. This study will randomize eligible patients to receive a standard chemotherapy regimen vs. one of two alternate high dose regimens.

Response Oncology is a comprehensive cancer management company that establishes and manages local cancer care networks. The Company (1) owns and/or operates a national network of advanced cancer treatment centers, or IMPACT(R) Centers, providing stem cell supported high dose chemotherapy under the direction of practicing oncologists; (2) owns the assets of and manages the business aspects of oncology practices and manages certain business aspects of oncology IPA's; and (3) conducts clinical trials for major pharmaceutical companies. The Company has over 300 affiliating oncologists.