Researchers presented the first comprehensiveresults of Neoprobe Corporation's pivotal multicenter studies of its RIGScan product at The Society of Surgical Oncology's (SSO) 49th Annual Cancer Symposium in Atlanta on March 22. The product is used with Neoprobe's proprietary RIGS technology for surgical detection of metastatic colorectal cancer. The RIGS system consists of cancer-specific targeting agents, such as RIGScan CR49, hand-held gamma detectors, and methods for their use.
The results of the clinical trials were reported at a special symposium entitled "Strategies to Lessen Our Current Failure Rate in Colorectal Cancer" held at the SSO meeting. The panel presentation was moderated by Kirby I. Bland, MD, of Brown University School of Medicine, who is also a member of Neoprobe's Scientific Advisory Board. Four other leading cancer researchers participated in the symposium.
"This symposium continues our efforts to keep our members informed about the latest theories and treatments for colorectal cancer," said Dr. Bland, who was recently elected President of the SSO. "Although the incidence of colorectal cancer in the United States has decreased slightly, it is ranked third highest in causing cancer deaths. Almost half of patients die of the disease. Surgery is still the most effective treatment. New research and innovative techniques are the best hope for improving our ability to treat these patients successfully."
Speakers joining Dr. Bland in the symposium panel included Isaiah Fidler, phd, University of Texas M.D. Anderson Cancer Center, who spoke on "The Metastatic Cancer Cell," Glenn Steele, MD, PhD, Pritzger School of Medicine, University of Chicago, who discussed "Molecular Mechanisms in Tumor Growth", John Daly, MD, New York Hospital, Cornell University Medical Center, who provided a "RIGS Clinical Update," and
Jeffrey Schlom, PhD, National Institutes of Health, National Cancer Institute, who talked about "Future Carriers and Current Strategies to Upregulate Antigen Expression."
Results of Pivotal Trials in Metastatic Colorectal Cancer
Dr. Daly's talk included the first announced results of Neoprobe's trials involving metastatic colorectal cancer patients at 24 cancer centers and hospitals in the United States, Europe, and Israel.
The RIGS procedure helped surgeons find additional cancer in one out of every five evaluable patients (those who had biopsy-proven localized tumor and who completed the study). The additional tumor was confirmed by conventional pathologic tests. Both a CT scan and the surgeon had missed the tumor found by the RIGS system. Using this new information, surgeons changed surgical management decisions for most of the patients who had an additional RIGS-located tumor. Surgical management changes included removal of more disease, abandoning the surgery if disease was found to be too widespread, or removing more tissue at the edges of the tumor in an effort to ensure complete removal.
"Optimal treatment for each patient depends on knowing the full extent of the patient's cancer," Dr. Daly stated. "When the RIGS system gives more information than ordinarily is available, surgeons are able to individualize treatment for those patients more accurately."
The results of these pivotal clinical trials, along with those of previous studies with the same targeting agent for metastatic colorectal cancer, are the basis for Neoprobe's marketing applications for the company's first RIGS product. The applications are planned for submission in Europe and the United States. Neoprobe is currently involved in discussions and review of the phase III data with the FDA.
The company's full analysis of the pivotal trials will be completed upon submission of the marketing applications for RIGScan CR49. These trials are called "pivotal" because they are the last of a sequence of trials conducted to show the safety and effectiveness of a drug or biologic.
The RIGS system, a new diagnostic tool for surgeons, works by injecting a cancer patient before surgery with a low-level radioactive, cancer-specific targeting agent. During the operation, the surgeon uses the RIGS gamma-radiation-detecting probe to locate tissue that contains a significant amount of the radioactive targeting agent.