The National Cancer Institute is enrolling 400 women who have been treated for advanced-stage ovarian cancer in a new clinical trial that aims to find biomarkers that can predict ovarian cancer relapses.
If successful, the research could lead to the development of an alternative to an existing test for the disease and its relapse, which some scientists say does not predict relapse well because of its relatively poor sensitivity.
Over 80 percent of advanced stage epithelial ovarian cancer patients see their cancer return after being treated with standard chemotherapy, according to the NCI. CA-125, the only marker currently approved by the US Food and Drug Administration to predict ovarian cancer and its relapse, is not a very good tool for predicting disease relapse because the marker is elevated in some, but not all, women who have relapses, according to some scientists.
Moreover, elevation of the marker may precede clinical evidence of disease relapse by as much as six to 10 months, but it may also lag behind clinical relapse by the same time intervals.
"CA-125 is currently the only approved test to see if ovarian cancer has returned, but it is not able to reliably diagnose women who have no signs of ovarian cancer," said Elise Kohn, the leader of the new study who is the chair of the gynecologic oncology faculty at the NCI's Center for Cancer Research. "If we can harness all of the protein information in our patients' samples, we may have a strong lead on how to detect ovarian cancer at an early stage when it can most effectively be treated."
"If we can harness all of the protein information in our patients' samples, we may have a strong lead on how to detect ovarian cancer at an early stage when it can most effectively be treated."
Rather than testing particular biomarkers that have already been discovered, the study's primary initial goal will be to create a repository of blood samples from women who have been treated for advanced-stage ovarian cancer. Specifically, researchers are looking for women who have completed their first program of chemotherapy within nine weeks of starting the trial, and who show no evidence of the cancer following the treatment. Treatment would involve receiving drugs such as carboplatin, cisplatin, paclitaxel, or docetaxel.
"Once the repository is in place, then it can be used to look at what's the best technology out there [for detecting ovarian cancer], or to develop a new test," said Mike Miller, a spokesman for the NCI.
Miller said it is unclear whether the repository will be available to researchers outside of the study.
"That's the institute's ultimate goal — to make repositories available to other researchers — but whether that will be achievable through this trial, I don't know," said Miller.
Kohn did not return telephone calls seeking comment.
In 2000, Kohn initiated a pilot study to try to develop a mass spec-based protein fingerprint profile associated with relapse. The study has enrolled about 25 patients out of a goal of 40. No results are available yet from the study because data are still being collected from certain patients, according to the NCI.
Kohn also collaborated with Lance Liotta, formerly of the NCI, and Emmanuel Petricoin, formerly of the FDA, in a study that showed that mass spectrometry-based patterns of proteins found in blood of ovarian cancer patients may be useful as early biomarkers of the disease (see ProteoMonitor 2/18/2002). The study was published in 2002 in The Lancet.
While Liotta and Petricoin's mass spec pattern-based test has now been developed by Correlogic and LabCorp into a test called OvaCheck, which has been licensed for commercialization by Quest, Miller said the current NCI trial has nothing to do with OvaCheck.
"This [trial] is in no way related to OvaCheck," he said. "That was a test being developed independently by industry."
In addition to enrolling 400 ovarian cancer patients, the NCI trial will also enroll 150 patients who have no evidence of the disease. It will take an estimated 18 months to enroll all of the patients, Miller said.
Aside from the NCI, 10 other sites will also enroll patients during the remainder of 2005 and 2006. Those sites are: the Fred Hutchinson Cancer Research Center and the University of Washington; Cedars Sinai Medical Center; the University of Alabama at Birmingham; Duke University Medical Center; Fox Chase Cancer Center; University of Texas MD Anderson Cancer Center; Massachusetts General Hospital; Northwestern Memorial Hospital; Evanston Northwestern University Hospital; and the New York University School of Medicine.
While the first priority of the new clinical trial is to develop a repository, rather than to create a new mass spec pattern-based diagnostic to predict the relapse of ovarian cancer, the creation of a new test seems like one of the likely goals for the future.
"The study will compare the blood protein test that is developed with CA-125 to see if it is better at predicting return of cancer than CA-125," NCI officials said in a statement. "Additional blood samples will be stored to create a repository so that other promising blood tests for ovarian cancer may be studied."
Miller said it is unclear what "the blood protein test" will be based upon.
In terms of "other promising blood tests," there are a number of them out there: Correlogic's OvaCheck is one. Another test, based on a panel of three biomarkers discovered using SELDI by a Johns Hopkins research team, is being co-developed by Ciphergen and Quest (see PM 7/8/2005, 7/29/2005). Yet another test based on a panel of four biomarkers was recently developed by researchers at the Nevada Cancer Institute (see PM 5/13/2005).
NCI officials said their goal is to create the "best, most accurate, validated test," which could be based on mass spec patterns or on another type of technology.
— Tien-Shun Lee ([email protected])