The FDA approved the first DNA test for human papillomavirus (HPV) that can be used alone to help a health care professional assess the need for a woman to undergo additional diagnostic testing for cervical cancer. The cobas® HPV Test was first approved in 2011 for use either in conjunction with or as a follow-up to a Pap test; the test is now also approved as a co-test or as a primary cervical cancer screening test. The FDA was careful to stress that the expanded approval of the cobas HPV Test does not change current medical practice guidelines for cervical cancer screening, because those guidelines are set by other groups, not the FDA.
HPV is the most common sexually-transmitted infection (STI) in the United States, with more than 40 types of HPV that can affect the genital areas, mouth, and throat of both males and females. Most people with the HPV virus are not aware of the infection because there can be very few symptoms and the virus can lay dormant for years. There is no test to determine whether a person is infected with HPV.
In many cases, the virus does not cause any health problems, but it can cause genital warts and many types of cancer, including cervical, vulvar, vaginal, anal, penile, mouth, and throat cancers. Nearly all cervical cancers are caused by HPV; 90 percent of squamous cell anal cancers, 50 percent of vulvar cancers, 70 percent of vaginal cancers, 30 percent of penile cancers, and 50 percent of oropharynx (the middle part of the throat) cancers are HPV-related.
cobas HPV Test
The cobas HPV Test is manufactured by Roche Molecular Systems, Inc., in Pleasanton, California. It uses a sample of cervical cells to detect DNA from 14 high-risk HPV types; the test specifically identifies HPV 16 and HPV 18, and detects the presence of 12 other types. Based on the cobas HPV Test’s results, women who test positive for HPV 16 or HPV 18 should have a follow-up colposcopy. Women who test positive for the 12 other types of HPV should have a follow-up Pap test to determine whether a colposcopy is necessary.
The FDA considered a study of over 40,000 women 25 or older that supported the use of the test as a primary screening test for cervical cancer. The study used the cobas HPV Test on women with negative Pap and cervical cell screenings for HPV, as well as on women who had a positive Pap or whose cervical cells screened positive for HPV. The test subjects then underwent a colposcopy and cervical tissue biopsy; the biopsy results were compared with the Pap and cobas HPV Test results. The study showed that the cobas HPV Test is safe and effective as a primary screening test for cervical cancer in women age 25 and older.
Disapproval of Health Organizations
In a letter to FDA Commissioner Margaret Hamburg, 17 organizations expressed “grave concerns” about the cobas HPV Test as a primary screening tool. The letter called approval of the cobas HPV Test a “radical change to current U.S. Preventive Services Task Force (USPSTF) guidelines,” and pointed out that “no U.S. guidelines currently sanction HPV testing as a first-line screening test for cancer.” The organizations, which include the American Medical Women’s Association, the American Public Health Association, the National Organization for Women, and the Cancer Prevention and Treatment Fund, believe that the harms associated with DNA testing outweigh any benefits that may result. They are concerned that the new test approval will interfere with the practice of medicine and result in the disposal of clinically important information. The letter also referred to what the organizations saw as flaws in the design of the clinical trials submitted to the FDA in support of the expanded approval of the cobas HPV Test. Overall, the organizations hoped that the FDA would reject the use of the test as a primary screening tool until additional studies confirm that the effectiveness of screening for cervical cancer would not be reduced.