October 2008: Volume 34, Number 10
AlloMap Test Cleared for Managing Heart Transplant Patients
FDA announced it has cleared as an IVDMIA XDx’s AlloMap test for helping physicians manage possible organ rejection in heart transplant patients. AlloMap measures the expression of 20 genes in the patient’s white blood cells and delivers a score indicating whether the patient might reject a transplanted organ. Traditionally, clinicians have relied upon heart biopsies to determine whether a patient is rejecting a transplanted heart, but these biopsies can be difficult to perform and risky for the patient. The third IVDMIA cleared by the FDA, XDx developed the AlloMap test using samples and information collected from heart transplant recipients at nine U.S. heart transplant centers participating in the Cardiac Allograft Rejection Gene expression Observational Study (CARGO). CARGO data included 153 patients and 300 medical visits at varying times after heart transplant.
FDA Asks LabCorp about OvaSure Test
In what could be another case of FDA looking to regulate a laboratory-developed test under the newly-coined IVDMIA rubric, OIVD Director Steven Gutman wrote to LabCorp asking to discuss its OvaSure test, a screening test that looks for early-stage ovarian cancer in high-risk women. LabCorp said the blood test uses six biomarkers to discriminate between disease-free women and those with ovarian cancer (stage I-IV) with high specificity (99.4%) and sensitivity (95.3%). These numbers come from a Yale study with grant support from LabCorp (Clin Cancer Res 2008;14:1065–72). In the letter, Gutman wrote that based on FDA’s review of LabCorp promotional materials and the research study, FDA believes LabCorp is “offering a high-risk test that has not received adequate clinical validation, and may harm the public health.” Gutman said that the study LabCorp used to come up with such high numbers for specificity and sensitivity was carried out on populations that were biased for being healthy and normal.
In a written statement to CLN, a LabCorp spokesperson said that “LabCorp shares the FDA's determination to help assure that patients are protected without unnecessarily imposing unnecessary regulatory burdens on new critically needed tests. LabCorp looks forward to working with the agency to review the clinical data related to this important test and continuing to advance the early detection of ovarian cancer for high-risk patients.” FDA issued a draft guidance in 2007 on IVDMIAs (in vitro diagnostic multivariate index assay), asserting its right to use its discretion in regulating home-brew test that involve multiple variables which combine to produce a patient-specific result. FDA’s letter is available online.
FDA Approves DNA Test for HBV Viral Load
Roche announced the FDA approval of its cobas TaqMan HBV test, the first FDA-cleared assay for quantitating HBV DNA. The test uses proprietary real-time PCR technology to quantify the amount of HBV DNA in a patient’s blood and can help physicians establish a baseline level of infection or asses a patient’s response to therapy. The cobas TaqMan HBV test detects WHO HBV International Standard in plasma and serum as low as 3.5 IU/mL and 3.4 IU/mL, respectively. The test can measure HBV DNA as high as 1.108 IU/mL, a broader dynamic range than previously available tests. The test runs on Roche’s cobas TaqMan 48 analyzer.
Instrumentation Laboratory’s D-Dimer Assay Gets Expanded Clearance
FDA cleared expanded use for the HemosIL D-Dimer assay to now exclude VTE in outpatients suspected of DVT and PE. Under the expanded-use clearance, the assay must be used in conjunction with a clinical pretest probability assessment model. The HemosIL D-Dimer assay is fully automated on IL’s ACL analyzers, with results in less than 7 minutes. In a multi-center clinical study conducted in preparation for FDA review, a cutoff value of 230 ng/mL yielded a negative predictive value of 100% for DVT and PE on the company’s ACL TOP hemostasis system.