NEW YORK (GenomeWeb) – A research group in Maputo, Mozambique has evaluated a prototype HIV viral load assay from Alere and shown that, while point-of-care testing is tantalizingly feasible, the particular assay is not yet ready for clinical use.
The study was based on an early prototype of the test and Alere has already made significant additional developments, a spokesperson at Alere emphasized in an email to GenomeWeb.
Alere has been developing both qualitative and quantitative HIV tests on its Alere q platform, which is designed to enable rapid testing in low-resource settings, as previously reported.
A qualitative assay, called the Alere q HIV-1/2 Detect, received CE marking in 2015. The company is also developing a quantitative test for whole blood, a prototype of which was evaluated in the Mozambican study published this month in the Journal of Clinical Microbiology.
However, the evaluated assay "is not the HIV1/2 Whole Blood assay that we will bring to commercialization," the Alere spokesperson stressed.
Ilesh Jani, director general of Mozambique's National Institute of Health, co-authored the JCM study as well as a previous evaluation of the Alere q HIV-1/2 Detect which showed that test was comparable to lab-based testing for early infant HIV diagnosis.
Jani explained that the evaluation, which was conducted in collaboration with the Clinton Health Access Initiative, was motivated by the urgent need the country is facing for point-of-care viral load monitoring.
More than 1 million of Mozambique's 25 million inhabitants are infected with HIV, Jani said in an email.
"Most of these people live in poverty and in settings where access to a health facility is problematic, [and] the health system is faced with many challenges and struggles to provide quality care, including laboratory testing, to patients."
Viral load testing is considered an important component of quality HIV care and is used to monitor response to anti-retroviral treatment (ART). But only a small proportion of patients in Mozambique currently have access to it. And the implementation of classical, laboratory-based testing in the country has been faced with many delays, mainly due to weaknesses in the health system, Jani said.
"Against this background, point-of-care assays for viral load could provide same-day results to patients and clinicians, even in hard-to-reach areas of the country, [and] same-day results for critical tests have been shown to increase efficiency of medical care and to have positive impact on patient-important outcomes."
The evaluation of the Alere system and viral load assay was investigator-initiated, and the Mozambican group purchased all platforms and tests used in the evaluation. Alere provided initial training on the use of the platforms but had no role in the design of the study or analysis of the results, Jani said.
In the study, finger-prick capillary whole blood and paired venous plasma samples were collected from 443 HIV-positive study participants, about 80 percent of whom were receiving ART. The Alere test was compared to a lab-based quantitative plasma HIV RNA test from Roche.
The results showed biases in the Alere assay results at low viral loads with respect to the comparator test, with the Alere test yielding higher counts than the lab test. On the other hand, for samples with more than 10,000 copies per ml of HIV RNA the bias was very low, Jani said.
The study also showed the Alere prototype test failed to detect HIV RNA in about 20 percent of specimens whose low levels of RNA were detectable by the lab-based test. This was "most probably due to the fact that the Alere platform uses only 25 microliters of whole blood ... compared to 500 microliters of plasma used by the laboratory-based test," Jani said.
"Our results show that HIV viral load testing at point-of-care is feasible but the evaluated platform is not yet ready for routine clinical use," Jani said, but added that he does not see these results as bad news.
"This is the first paper describing the feasibility of a point-of-care assay for viral load at a primary health care level facility," he emphasized. Furthermore, the Alere assay had good agreement with the gold standard method for patients with high viral loads.
Interestingly, the elevated counts in low viral-load samples may be attributed to the difference in the biomarker being measured, Jani suggested.
"The Alere assay measures total HIV RNA while the current 'gold standards' measure plasma HIV RNA, [and these are] two different biomarkers," he said.
Other reports have also begun addressing this issue, since small volumes of whole blood are the ideal sample type for low-resource settings, obviating the need for phlebotomy and centrifuging to obtain plasma.
Jani pointed to a JCM study published earlier this year evaluating dried blood spots versus plasma RNA. This research suggested that HIV-1 DNA co-amplification occurs during HIV-1 RNA quantification of whole blood, and false-positive HIV RNA detection was associated with high HIV-1 DNA levels. Jani also noted that a "total HIV RNA," or a whole-blood test, could also detect RNA in cellular elements which would increase detected levels, and that clinical guidelines on ART treatment have been developed for plasma HIV RNA detection.
"We feel that total HIV RNA is a new biomarker, for which little is understood in terms of clinical usefulness," Jani said. "This is an area where more research is needed."
The Alere spokesperson noted that the company has submitted the CE-marked Alere q HIV-1/2 Detect qualitative assay for WHO prequalification and approval is pending, which would make it available for public sector procurement in resource-limited settings.
"A critical and urgent application will be early infant diagnosis in the fight to eliminate pediatric AIDS. Alere q HIV-1/2 Detect can also serve as a vital tool in diagnosis of HIV in other key populations," the spokesperson said.
An Alere q Filovirus Detect assay is also undergoing final stages of clinical validation for regulatory submissions, the spokesperson said, and the company has a pipeline of additional analytes including a plasma HIV viral load assay on the Alere q platform that it expects to submit for CE mark next year.
In other words, Alere plans to bring to market a number of HIV viral load assays. The plasma-based viral load assay is scheduled to debut in late 2016 or early 2017. "At the same time we are working on perfecting a whole blood [viral load] assay," the spokesperson said. "One does not replace the other – they are separate assays and we intend to bring both to market."
In a call following the firm's third quarter earnings last year, Alere's CEO and President Namal Nawana said the company had shipped over $1 million in Alere q products over the previous two quarters, and that the firm is "excited about the opportunity for this point-of-care molecular platform going forward."
Alere subsequently delayed filing its fourth quarter and full-year 2015 earnings in order to review revenue recognition in Africa and China. The company was soon after subpoenaed by the US Department of Justice, initiating an investigation of its business practices in Africa and other global locations. However, "this investigation has absolutely nothing to do with the development of the Alere q," the Alere spokesperson said, adding that the firm does not comment on ongoing investigations and is fully cooperating with the DOJ.
Meanwhile, HIV viral load measurement at the point of care continues to be a critical need in sub-Saharan Africa. At the time of the evaluation, Alere's test was the only point-of-care platform for HIV viral load that was suitable for implementation at the primary health care level, Jani said. However, a point-of-care test on Quidel's Savanna platform is slated to enter field studies this year. Cepheid's HIV viral load test has been CE-marked on the GeneXpert platform and the firm has described plans to bring that test onto the Omni point-of-care platform, although Omni's development has since been delayed. And Iquum had HIV whole blood and plasma tests on the Liat platform when Roche purchased that firm, although whether Roche will choose to develop those further is unclear.
In Mozambique, Jani said he and his colleagues are "aware of the pipeline of HIV related point-of-care assays [and] we are hoping that there will be healthy competition between all these platforms."
Jani said that he expects each one of the assays to reach the market with good analytical performance, a fair price, and feasibility for implementation at primary health care level. "Ultimately, these features will be the drivers of success and market share," he said.
In the meantime, the group will not be using the Alere q HIV viral load test prototypes on patients, in part because the assay is "not yet on the market nor approved by any international regulatory body," Jani said, but he noted that the qualitative test from Alere is currently being considered for implementation in some countries' health systems for early infant HIV diagnosis.