2012 Gastrointestinal Cancers Symposium
SAN FRANCISCO — A test using a monoclonal antibody to detect PAM4 protein and CA19-9 markers was able to detect 85% of patients with pancreatic ductal adenocarcinoma, according to data presented at the 2012 ASCO Gastrointestinal Cancers Symposium.
Based on a previous study, in which a PAM4 blood serum-based test could identify 13 of 21 patients with stage I pancreatic cancer, researchers expanded the study to include 602 participants. According to the researchers, the new study divided participants into four groups: patients with pancreatic cancer, including pancreatic ductal adenocarcinoma (n=298); patients with cancers of the surrounding organs (n=99); patients with benign pancreatic disease, such as pancreatitis (n=126); and healthy adults (n=79). Sera from study participants were assessed by enzyme immunoassay for concentrations of PAM4 antigen levels.
“Early detection, in addition to better therapeutics, is urgently needed for patients with pancreatic cancer,” researcher David V. Gold, PhD, director of laboratory administration and a senior member of the Garden State Cancer Center in Morris Plains, N.J., said in a press release. “Pancreatic cancer symptoms are vague, and the disease tends to develop and grow silently. By the time it is detected, it has often spread to other parts of the body, making it nearly impossible to cure. These study results are extremely encouraging and may eventually lead to improved detection of the disease in high-risk individuals.”
According to the study, sera from patients with neuroendocrine tumors of the pancreas or cancers of other origin did not exhibit elevated levels of the PAM4 antigen, yet patients with ampullary (48%) and extrahepatic biliary (50%) adenocarcinomas demonstrated positive levels of circulating PAM4 antigen. In patients diagnosed with benign pancreatic diseases, 19% were identified as positive for PAM4 antigen — in particular, 23% of patients with chronic pancreatitis were identified as positive. The researchers observed that overall sensitivity for detection of pancreatic ductal adenocarcinoma was 76%, with 64% of stage I patients testing positive, and a higher sensitivity (85%) for advanced disease when the test was combined with the CA19-9 test.
“These results demonstrate that reactivity of the PAM4 antibody is highly restricted to [pancreatic ductal adenocarcinoma], with the biomarker present at the earliest stages of neoplastic development,” Gold said. “To the best of our knowledge, there are no biomarkers or target antigens that are expressed at a similarly high frequency and concentration in [pancreatic ductal adenocarcinoma], and which show such specificity.”
According to the researchers, the test may hold promise for early detection of pancreatic cancer in those at high risk for the disease, as well as the development of personalized treatment for patients with pancreatic cancer with the use of PAM4-based imaging and therapy.
“Providers of care for patients with pancreatic cancer are always limited by an inability to readily detect this cancer, especially at earlier stages,” said Morton S. Kahlenberg, MD, a member of the 2012 Gastrointestinal Cancers Symposium News Planning Team. “[The study] shows tremendous promise that the serum or blood-based assay can add significantly to our ability to diagnose pancreatic cancer, hopefully at an earlier stage, thereby impacting patients’ lives.”
For more information:
- Gold DV. Abstract #151. Presented at: ASCO Gastrointestinal Cancers Symposium; Jan. 19-21, 2012; San Francisco.
Disclosure: David M. Goldenberg, ScD, MD, reported an employment/leadership position and stock ownership with Immunomedics.