BETHESDA, MarylandA new proteomics blood test for ovarian cancer (developed by researchers at the joint Food and Drug Administration/National Institutes of Health Clinical Proteomics Program) detected all 50 ovarian cancers in a proof-of-principal trial and is now being validated in a major study of recurrence in stage III/IV ovarian cancer.
The new approach also will be used as a monitoring tool in the first study of imatinib(Drug information on imatinib) mesylate (Gleevec) in ovarian cancer, a phase II trial expected to open soon.Emanuel F. Petricoin III, PhD, co-director of the Clinical Proteomics Program, told ONI, "This represents an entirely new approach to detecting cancer because it uses the pattern of proteins in the blood as the discriminator, independent of (and indeed without knowing) the identities of the individual proteins.")
Dr. Petricoin is senior investigator in FDA’s Center for Biologics Evaluation and Research. Co-Director on the NIH side is Lance A. Liotta, MD, PhD, from NCI’s Center for Cancer Research. The study was fast-tracked for publication by The Lancet (359:572-577, 2002) and is available free at the journal’s website www.thelancet.com.
The new test takes a small drop of blood, determines the pattern of proteins present, and compares that with the proteomic patterns known to be associated with cancer. The whole process takes about 30 minutes.
In the pilot study, the algorithm identified a cluster pattern that correctly detected all 50 cancer cases, including 18 stage I cases, in a masked set of samples from a population of women at high risk for ovarian cancer. The pattern also correctly identified 63 of the 66 cases of nonmalignant disease.
The resulting 100% sensitivity and 95% specificity yielded a positive predictive value of 94%far higher than the 20% positive predictive value now possible with CA-125 combined with ultrasound.