NEW YORK (GenomeWeb) – Researchers using the Cepheid GeneXpert human papillomavirus test in Papua New Guinea have shown that patient-collected samples produce results similar to physician-collected samples.
The study, published last week in the Journal of Clinical Microbiology, adds to a growing body of evidence supporting the use of self-collected specimens for HPV and other infectious disease testing in both the developing and developed world.
Allowing women to collect their own gynecological samples may be more culturally acceptable and cost-effective than having a clinician collect them, especially in parts of the developing world. When the samples are used for cervical cancer screening, this could also save lives. Papua New Guinea has one of the highest burdens of cervical cancer globally, accounting for 1,500 deaths per year.
"Getting high levels of patient compliance with collection of cervical samples for HPV testing has always been a challenge, especially in developing countries," David Persing, Cepheid's chief medical officer, told GenomeWeb in an email.
Persing noted the Papua New Guinea study, for which Cepheid supplied test cartridges, was well-controlled and enrolled over 1,000 subjects, and HPV detection from self-collected vaginal samples showed a high degree of correlation with clinician-collected cervical specimens.
"This bodes well for same-day test and treat programs being evaluated in developing countries," Persing said.
The authors also noted that none of the women invited to participate in the research study refused. Patients received the results the same day, and were offered same-day cervical cryotherapy if they tested positive.
The study demonstrated similar cycle thresholds between sample types, suggesting viral loads may be equivalent. The authors said that a handful of tests in which the self-collected sample was positive while the physician-collected was not suggest perhaps the former may be more sensitive. This could be due to PCR inhibitors in cervical mucus, they said, but added that the presence of internal controls in the Cepheid test make this hypothesis seem unlikely.
Validating self-collection methods with patients using the numerous commercially available molecular HPV tests is an arduous process, however, and whether self-collection will ever become widely available in the developed world remains to be seen.
Cepheid has been testing self-collected samples for another sexually transmitted infection at a clinic in the UK. "Pioneering efforts by the Dean Street Clinic in London have shown high levels of patient satisfaction and compliance with self-collection protocols for [Chlamydia trachomatis/Neisseria gonorrhoeae (CT/NG)]," Persing said.
"Similar approaches to cervical cancer screening may eventually 'trickle up' to the developed world as well," he added.
Cepheid's CT/NG test is cleared for use with all the major sample types —urine from males and females, endocervical swabs, and self-collected vaginal swabs that are collected in a clinical setting. At Dean Street, CT/NG testing is conducted with self-collected specimens, and Cepheid claims 175,000 CT/NG tests were run there in 2015. The point-of-care testing strategy provided results to patients in about four hours, reducing the proportion of patients who did not return for follow-up from about 16 percent to 3 percent.
The firm's HPV test, meanwhile, was launched in Europe in 2014, but in a third-quarter earnings call last year the firm noted that it is not yet in a position to fully compete in the primary screening market there until it meets certain European HPV guidelines. Cepheid said it had generated data on clinical performance and reproducibility, and hoped to meet the standards and begin competing in the primary screening opportunities outside the US in 2016.
Other firms are also pursuing patient-collected samples for molecular tests. Becton Dickinson has a claim for self-collected vaginal swabs for CT/NG, as previously reported. And its CE-marked test for Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis from a single specimen can use this sample type as well. Meridian's CE-marked CT/NG test has such claim. And Roche, whose HPV test was recently adopted by the Netherlands for all cervical cancer screening, also has a self-collection claim.
Molecular testing for HPV is currently incorporated into cervical cancer screening guidelines in the US, Europe, and Australia. The World Health Organization has also recommended it, when feasible, for low- and middle-income countries. Yet, molecular tests can be costly, and HPV tests usually require a pelvic exam to obtain a swab of the cervix, which adds the cost of clinician time.
Self-collected specimens can save clinician costs, and have been in development for a number of years, but none has really taken off as a companion sample collection method to any molecular diagnostic test. Also, while a clinician-collected sample is usually swabbed from cervical cells, patient-collected samples are often vaginal swabs. This has led to concerns that this sample type may not be as sensitive for cervical cancer screening.
However, there are signs that self-collection is becoming more widely embraced for HPV testing. It has been evaluated in the developing world and in rural areas, in places such as Madagascar, Haiti, Thailand, Egypt, Nepal, Brazil, and rural China, and it has been used in studies of HPV epidemiology in Cameroon.
A study in India showed that self-collected samples may have lower viral load on average but they have equivalent ability to detect patients with high-grade cervical intra-epithelial neoplasia, which may be the most important outcome.
Finally, a large analysis by PATH performed in India, Nicaragua, and Uganda tested the CareHPV assay from Qiagen and showed self-collected samples were on par with clinician-collected. Qiagen's CareHPV received approval from the China State Food and Drug Administration in 2012, although the firm last year reported HPV sales losses in the US due to pricing pressures.
There have also been a few studies in select populations in higher-income countries. Mailing a self-collection kit was shown to be more effective than a letter reminding women to visit the doctor in rural Ontario in order to get under-screened women tested. In Newfoundland, self-collection increased screening rates. Among an immigrant community in Texas, self-collection was found to be highly acceptable to women who otherwise would not attend screening, and researchers in St. Louis have recently evaluated pairing online recruiting with self-collection.
Australia plans to offer self-collected samples as part of its new policy recommending HPV testing every five years for women ages 30 to 74 years. Self-collection will be an option for women who have never been screened or who are overdue for screening by more than two years.
Researchers in that country recently performed a simulation which showed a single round of self-collected testing at age 30 could prevent 364 cancer deaths by age 84 in a cohort of 100,000 women. They noted, however, that testing every five years would prevent significantly more deaths and that self-collection may ultimately be a way to encourage women to get more frequent check-ups.