Multiplex Immunoassays Could Develop as a Cheaper Panel Testing Option for Tropical Diseases
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The sensitivity and specificity of nucleic acid analytes provide molecular diagnostics key advantages in clinical practice, particularly in critical health situations. Nucleic acid amplification (NAATs) or molecular tests are now open to routine and distributed use in healthcare thanks to advancements in microfluidics and molecular reagents. As molecular diagnostics enter point-of-care (POC) settings, cost becomes a key issue in comparison to predominantly used and cheaply performed rapid immunoassays. In routine testing applications such as screening, test cost is often prioritized over performance, especially in low-resource health systems. High-burden tropical diseases in the developing world such as malaria represent a significant market opportunity for molecular POC tests, but must displace or compete against rapid immunoassays in established screening programs or future initiatives. Significant cost reductions will be necessary for molecular diagnostics to penetrate such markets, and only then may be limited to relatively niche applications.
Emblematic in terms of where the infectious disease POC testing market is heading and the competitive challenges awaiting molecular POC products, rapid test specialist Chembio Diagnostics recently announced plans to develop a single test for 9 febrile illnesses. Multiplex testing of infections with similar symptoms or Syndromic panel testing is increasingly used in healthcare to quickly diagnose patients during admission and initiation of care. Developing a single test on an immunoassay format would be an achievement in rapid syndromic testing, and available at potentially a fraction of the cost for rapid molecular tests. Chembio will collaborate with the Geneva-based Foundation for Innovative New Diagnostics (FIND) to develop a multiplex rapid immunoassay for malaria, dengue fever, Zika virus, chikungunya, leptospirosis, Rikettsia typhi, Burkholderia pseudomallei, and Orientia tsutsugamushi. The Chembio DPP Fever Panel is intended for syndromic panel testing in the Asia-Pacific region.
Rapid malaria tests represent the highest volume test market in the developing world with over 300 million tests procured annually, an estimated global need for over 1 billion tests annually, and over 3 billion people at risk for infection. The average test costs something in the range of $0.35-0.50 depending upon its ability to detect P. falciparum only or multiple malaria pathogens. Market consolidation has also been a strong pricing factor with only two principal manufacturers, Standard Diagnostics (Alere) and Access Bio with Premier Medical Corporation (PMC). Distribution of a multiplex assay such as Chembio’s Fever Panel will be difficult to achieve at the scale of rapid malaria assays, even if other specialized disease panels were developed for other regions. The added cost of a multiplex panel will make displacement of cheap malaria assays very difficult, but panels should find lower volume usage as a follow-up test to negative results for malaria.
The uphill battle to market facing rapid multiplex immunoassays in the developing world is even steeper for molecular POC tests. In Kalorama Information’s molecular POC diagnostics report, molecular syndromic panels for tropical and neglected diseases were estimated to have an achievable market of approximately $25 million by 2020, but only at a price point of $20 or less per test. The market opportunity may be even slighter if competitors such as Chembio introduce cheaper multiplex immunoassays. The best fit for molecular diagnostics in testing for febrile illnesses in the developing world would be low-transmission areas where resources could be diverted to the sensitive diagnosis of passive cases, special populations and focused clinical investigations taking advantage of molecular diagnostics’ superior performance characteristics.