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Out of Africa: Special report on point-of-care diagnostics
Sitting at a table in a makeshift clinic several miles outside of Apesika, Ghana, HIV patient Bekoe Mahama leans forward to spit onto a small strip of paper handed him by a clinician. The doctor asks him how the antiretroviral therapy (ART) has been treating him and if he needs any other assistance. Glancing at the paper strip, the doctor smiles. Bekoe is showing no signs of liver damage. He can continue his ART.
Half a day and half a world away in a nondescript office tower just outside Dallas, HIV patient Jarod Smithson sits in a brightly lit exam room as a medical assistant draws a vial of blood. As the assistant bandages Jarod’s arm, she tells him that he’ll get a call from his doctor’s office in about a week when the results come back. Until then, he should continue his ART as prescribed. This is always the longest week for Jarod.
A tale of two systems
An admittedly made-up pair of scenarios, but an increasingly likely description of two healthcare systems moving in opposite directions to achieve the same ends.
In the industrialized world and especially the West—the United States being a particularly good example—a massive system of healthcare machinery designed to facilitate well-being, often while turning a profit. In the developing world, often a piecemeal system trying to spread healthcare while minimizing costs.
In an editorial published last year in Clinical Chemistry, Harvard scientist George Whitesides quoted a 2012 study that suggested the United States expends about 17 percent of its gross domestic product on healthcare.
“At that expenditure rate, it has a healthcare system that is the most expensive per person in the world, but certainly not the most effective (in fact, by some measures, it is surprisingly ineffective),” Whitesides wrote. “In the U.S., diagnostics are based on a capitalist motivation: expensive tests, reimbursed separately as procedures, can be a good business.”
This attitude, he argued, can lead to expensive and yet sometimes poor healthcare.
One hope to reduce the costs associated with healthcare, if only by making it more immediate and ensuring patients receive the right treatment as quickly as possible, is point-of-care (POC) diagnostics, the most commonplace examples being home pregnancy tests and portable blood sugar monitors.
According to a Grand View Research report released in January, the global market for POC diagnostics could surpass $18.5 billion by 2020 from its 2012 value of $13.5 billion, although market estimates vary wildly between different research firms.
One thing that is consistent across these reports, however, is that global demand is being driven by the increasing prevalence of “lifestyle diseases” such as diabetes and cardiovascular disease, with the former accounting for more than 10 percent of the global revenues in 2012.
For this reason, it is perhaps not surprising that North America dominates this market, representing about 35 percent in 2012, with Europe bringing up second place. The U.S. Affordable Care Act is also expected to expand the number of people entering the insurance rolls and further add impetus to the expansion of the POC diagnostics market.
Although the developed West generates the lion’s share of POC revenues, emerging markets such as China, India, Latin America and parts of Asia and Africa are showing the strongest growth.
“The slowly but steadily growing trend towards automation in emerging countries is likely to provide future opportunities for market growth as laboratories and hospitals focus on modernization,” said Frost & Sullivan Healthcare Senior Research Analyst Srinivas Sashidhar in a 2013 report. “The market will also be propelled by the higher number of new products and increased patient awareness of diagnostics.”
As suggested in the scenarios presented above, however, the developed and developing worlds are two very different market spaces.
Because of limits in resources and training in many developing regions, however, new POC systems are required that are much simpler to use and more robust than typical developed-world systems to be at all practical in diverse settings. It is not sufficient, although necessary, to be less expensive.
“If you have seamless 24-hour logistics, perfect cold chain, and Internet results, it is less clear that you need POC,” opines Marcus Lovell Smith, president and CEO of non-profit Diagnostics For All (DFA). “They’re pretty efficient. Their 200,000 square-foot central laboratories are probably a pretty efficient place to push through tests.”
“In the developing world, POCs a given because you’re in a level-zero clinic, you have no power, you are 10 miles away from any form of more well-equipped clinic,” he adds. “Therefore you have to deliver diagnostics, if people are going to have them at all, at point of care.”
A decade ago, the World Health Organization (WHO) issued guidance for successful POC diagnostics development in resource-poor settings, anointing their criteria with the acronym ASSURED: Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free and Delivered.
Thus, while much of the POC diagnostics development for the Western world has focused on issues around sensitivity and throughput, the focus in resource-poor settings has been on cost-containment, minimizing required infrastructure and ease of use.
The mantra here is to do as well or better than the developed world with less.
“The future development of POC molecular diagnostics will be driven by the needs of resource-limited areas, such as developing countries or in the home, where insufficient healthcare facilities exist for diagnostic support,” wrote Lidong Qin and colleagues at the Houston Methodist Research Institute, Cornell University and University of Texas at Austin in a recent review of POC molecular diagnostics (MDx).
Leaving a paper trail
DFA is focusing its efforts on embedding diagnostic and monitoring assays into thin paper strips. In the company’s mind, paper combines the best of all worlds (see also sidebar “Paper Lions” below).
“Professor George Whitesides of Harvard was really the moving force behind it and his low-cost approach to technology,” explains DFA’s Lovell Smith. “How do we use paper, which you know is a 5000-year-old technology, and adapt it? Because we know that if we start with that, we will end up with a very low-cost product.”
DFA’s flagship product is a paper-based multiplexed transaminase test used to monitor liver function in patients receiving treatment for HIV and tuberculosis. The drugs used in ART cocktails, for example, can significantly damage the liver in HIV patients, and clinicians are constantly at risk of doing more harm than good in treating these patients.
As DFA’s Jason Rolland and colleagues explained in a recent paper in Science Translational Medicine, monitoring hepatotoxicity in resource-limited settings can be complicated by both expense as well as logistical terms. Furthermore, many patients are adverse to venipuncture.
“Because of these obstacles, in many resource-limited settings, patients with TB and/or HIV receive minimal or no monitoring during treatment.”
DFA’s response was to create a microfluidic device of hydrophilic channels within a thin flexible strip and embedding the necessary filters and chemistries within the paper matrix to facilitate sampling from body fluids such as blood, urine, spit or even sweat.
“What you are trying to mimic is a full wet lab,” Lovell Smith says. “To mimic that you use a number of different papers and you treat them in a number of different ways to create the complexity you need to have to do what are traditionally instrument-based tests.”
The result is a postage-stamp sized strip that offers remote clinicians a visual cue within 15 minutes to liver enzyme levels in patients receiving treatment. Based on these results, the physician can then continue the patient on his or her current treatment, or change things up if the patient is reacting badly to the current regimen.
In December, DFA announced it had received funding from the Bill & Melinda Gates Foundation to adapt its technology and create a rapid diagnostic test for markers showing immunity in children vaccinated against tetanus and measles. One goal is to know whether current immunization efforts are effective.
“How do you know if a child or an area has been immunized?” Lovell Smith asks. “[The test] is a surveillance technique that allows you to take something as simple as a swab from an infant or child’s mouth and say: ‘Okay, the child has tetanus antibodies.’”
Going with the flow
Not satisfied with even a 15-minute test, scientists at MedMira have, in their words, combined the best of traditional lateral flow assays and flow-through technologies to develop diagnostic tests for various infectious diseases—assays that provide results in two minutes.
“When you look again at traditional lateral flow diagnostics or even the more modern multiplexing technology like DPP from ChemBio, they take a very long time to give a result,” says Kevin Jones, senior director of sales and marketing for MedMira. “For example, ChemBio HIV/syphilis tests can take between 45 minutes to an hour to give the results.”
“A traditional lateral flow test takes 15 to 20 minutes to give a result,” he adds. “It’s convenient. It’s in a POC format. You can do testing anywhere. But it’s not really rapid. When you look at our test, it gives the result in two minutes from the start of application of buffers.”
From a technical perspective, Jones suggests, a major problem with lateral flow tests is that the sample has to do all the work, from hydrating reagents to powering the flow through microfluidic channels. And because there is no wash step, he argues, it can be difficult to identify a weak positive result against a possibly colored background due to sample contaminants.
MedMira’s answer to these issues is a rapid vertical flow (RVF) platform where sample is dropped onto a membrane, a cap is attached and a couple drops of buffer are then added to transport the sample and wash the membrane.
According to Jones, the RVF platform also eliminates the chance of a false negative reading from something known as the hook or prozone effect, where any excess antigen in a strongly positive sample triggers competitive binding with the capture reagent, limiting colorimetric detection.
“For example, a woman at five to six months pregnancy would actually count negative on a lot of lateral flow pregnancy tests,” he explains. “There is just too much of the antigen present and that blinds the capture ion, and stops things from working.”
With their RVF-based Multiplo system, he argues, sample never passes through the conjugate, so you can’t overload the conjugate, even at very high positive results.
“The test may no longer be linear in terms of the relationship between sample and signal intensity, but at least you won’t get a false negative at very high concentrations.”
Jones equates the Multiplo with the gold-standard ELISA assay, used in centralized diagnostic facilities the world over, and foresees a time when the multiplexing of the units is ramped up using machine-based visualization. (The company’s current limit is a triplex assay for HIV, hepatitis B and hepatitis C infection.)
“By eye, we are limited to about five spots,” he says. “As soon as you get into a machine and you can up the precision and resolution, then the machine can make that determination based on 100-μm resolution not a half-centimeter.”
“You might never go to a 10-by-10 grid, but you could easily see a 3-by-3 or 5-by-5, looking for cross-reactions, looking for certain markers,” he continues. “Even looking at a condition with several different parameters; a bacterial infection perhaps where you could look at what different strains are causing that infection and prescribe the right antibiotic at that time.”
Jones admits that the Multiplo is slightly more expensive than many of the tests currently available in resource-limited markets, but suggests that the speed and multiplexing opportunities more than offset the total costs of testing.
“The actual cost of the test—especially in the developed world—is substantially less than the labor costs and overhead,” he says. “So when you’re looking at how to improve healthcare, to get screening programs out to more people, to get a better healthcare environment, a big step toward that is to reduce the major part of the cost. And if you can have a small increase in the price of the test but reduce your labor costs fivefold, that’s huge.”
For Jonathan O’Halloran, chief scientific officer of QuantuMDx, a significant challenge in getting the most out of MDx platforms lies in fully realizing its links to personalized medicine through genetic markers, but progress has been slow.
“This is due in part to limitations in technology, such as the complex and lengthy sample prep, or no true POC MDx device, but also due to a lack of data and clinical utility data supporting many of the mutations in humans and pathogens that would guide a clinician to make the correct treatment choice,” he says.
“With extensive data supporting the clinical utility of mutations/SNPs, cheap devices and tests, and fast (about 10 minutes) turn-around time, we will then have a platform for personalized medicine and effective decentralization can occur,” he adds.
“Obviously then interpretation and clinician education become an issue. However, with validated and clinician-led development of interpretative aide tools on the device, routine real-time personalized medicine will become a reality, not just in the West, but also in the developing worlds.”
“It's that last bit that gets me out of bed,” O’Halloran enthuses.
QuantuMDx is tackling the genetic links with their Q-POC device that can quickly be described as PCR meets biosensor. A handheld DNA analyzer, the device relies on disease-specific cartridges to identify specific genetic markers within samples such as a blood droplet. Within minutes, a treating clinician knows not only if the patient is infected with HIV or malaria but also whether the strain shows particular drug resistance patterns. This ability is critical, he suggests, in regions where one child dies every minute from malaria.
For O’Halloran, the sample prep technologies developed for the Q-POC were key.
“So many POC diagnostic technologies simply aren’t feasible because they require hands on-sample prep by highly skilled technicians using expensive laboratory equipment and sensitive reagents,” he says.
But marker identification isn’t the endpoint for QuantuMDx.
“The real kicker comes when we add DNA sequencing functionality to the device,” O’Halloran adds. “Then what you'll have is a cheap device sequencing pathogens all over the world, GPS-positioned, constantly monitoring emerging pathogen threats, performing pharmaco-survelliance such that we can identify new hot spots of drug resistance and learn about the dynamics of these mutations in populations.”
The company isn’t just limiting itself to infectious disease, however. Last May, QuantuMDx announced a collaboration with Genome Institute of Singapore to develop Q-POC assays for Asia-predominant forms of kinase-driven cancers like CML and EGFR-mutated NSCLC.
O’Halloran points to the emerging-markets success of a competitor to validate his company’s interests in the same region, pointing out that this isn’t a purely humanitarian push but also a potentially highly lucrative one.
“Looking at Cephied’s sales data to the middle and upper classes of countries in the developing world clearly demonstrate that these emerging markets are pulling MDx tech,” he explains, adding that success comes in addressing the unique challenges of these regions. “Think about this: the upper and middle class in India is larger than the entire population of Europe!”
“We will be commercializing first in Africa and India, and shortly thereafter will move into the other BRIC nations and other emerging markets,” O’Halloran adds. “We see that there will be huge growth in these markets. We want to be leading the way as we believe their growth with eventually overtake the POC markets in U.S. and E.U.”
Bringing it home
Unlike Vegas, however, what happens in the developing world doesn’t have to stay there, and many companies are looking to leverage their developments in emerging markets back home in the developed world, particularly as demand rises and budgets shrink.
“The common needs are simple, high-quality molecular analysis of infectious disease at a price point that is accessible and with more information than just a diagnosis,” says O’Halloran, suggesting that growing drug resistance in all pathogens means that a simple yes/no answer from a lateral flow device “is not cutting it anymore.”
For the folks at DFA, bringing technology back home is also about finding new sources of funding and revenue (e.g., royalties) that can then be plowed into their developing world initiatives (see also sidebar “All together now” below).
A good example of this might be the transaminase test, which could have a role for any type of therapy where liver toxicity could be an issue.
“When I last looked at a list, there were 35 drugs withdrawn in the U.S. over a number of years because of hepatotoxicity and diminished liver function,” says Lovell Smith. “The list of drugs that have been removed along with the list of drugs with black box labels is huge, as well as the drugs that could be but are not on the market because they have 1 or 2 percent patients who have an unacceptably high level of liver toxicity. If you can protect for that, then there might be a drug that could stay on the market.”
He suggests that such a test would be welcomed by the FDA, which is trying to facilitate safe drugs that improve or save patients’ lives without increasing the toxicity threat.
“I’d love to be involved in some projects like that,” he enthuses. “Just allowing a few drugs that would otherwise not be available to be available, that seems to be possible and an important thing to do.”
Such assays could also form the basis of companion diagnostics, an area of extreme interest to QuantuMDx.
“Companion diagnostics is an interesting area because there are so many drugs whose efficacy improves if you stratify patient populations,” offers O’Halloran. “With the changing healthcare system in the U.S. and stretched health budgets all over the world, stratification is the only logical route forward. To be able to quickly identify these people before the drug is prescribed will enable pharmaceutical companies to commercialize these drugs faster and hopefully cheaper.”
One of the challenges of developing companion diagnostics has been that the assays developed in the lab in creating the pharmaceutical product early on are not always amenable to large-scale application afterwards. MedMira may have a solution to this problem.
“We’ve just launched the Miriad RVF Toolkit. It’s our platform but available in a format for anyone to use,” says Jones. “The process is as simple as spotting down 0.5 to 1 μL of your capture material and letting it air dry for 30 minutes before running the test.”
A lot of people use ELISA to do their initial lab screening, which works very well, he says, but laments that there is no direct transfer for an ELISA test in the lab to a field test.
“With the Miriad kit, we haven’t just got something that is quicker and cheaper to run than an ELISA, we’ve also got a very clear scale-up process,” he adds. “It’s just an incredibly simple way of scaling up your lab process right the way through into full manufacturing.”
“You can actually start off on the lab bench with a scientist building the test for himself, and then have a clear path to commercialization as they want to scale-up from singles to hundreds to millions [of units].”
For MedMira, the development of a POC platform is less about focusing on the developing world over the developed world, but rather about making the most robust system with the broadest application.
“We want the best platform technology and then apply that across the globe. People talk about making something for the developing world,” Jones says, but many simply mean looking for ways to cut corners to cut costs.
“We don’t want to cut corners and have something that may be of lower quality going into the developing world,” he says quite adamantly. “Why should the developing world take a lesser technology? They deserve better.”
In a 2013 paper in the MRS Bulletin, George Whitesides and colleagues at Harvard and Rutgers Universities identified five properties that made paper uniquely qualified to serve as a matrix for chemical and biochemical diagnostic analyses.
1. Cellulose fibers promote capillary wicking of aqueous solutions, allowing fluids to transport without the need for external energy.
2. Assay reagents can readily be impregnated and immobilized within paper’s pores.
3. Transport and storage logistics are easier due to paper’s flexibility and light weight.
4. Methods for microfluidic channel patterning methods are well established.
5. Paper is relatively inexpensive and readily combustible, facilitating safe and disposable single-use test development.
That thinking is the basis for the platforms being developed at non-profit Diagnostics For All.
All together now
With most if not all initiatives focusing on the developing world, funding is a constant issue. Organizations like the Bill & Melinda Gates Foundation and the Clinton Foundation annually pour a fortune into such endeavors, but in January, QuantuMDx took an interesting and unusual step in this market.
They started an Indiegogo crowd-funding campaign.
“We are developing diagnostics for all, so it seemed natural that it be funded by all,” says company CSO Jonathan O’Halloran.
Their modest goal is to raise $50,000 to support a clinical trial of the company’s malaria diagnostic platform. With almost three weeks left in the campaign, which was to end in early April, the company had raised almost $18,000.
“This funding will principally fund test cassettes for clinical trials for our malaria infection/drug resistance tests,” O’Halloran explains. “We are specifically using this money to pay for tests for children who are enrolled in the trial.”
“Whilst a campaign that doesn't provide pre-sales of services or devices struggle to raise funds, we have already managed to raise a good amount of money and continue to raise funds,” he says in explaining why they went this route and asked for so little. “However, the real win for us is getting our name out there, showing that we are an exciting and innovative company that isn't afraid to operate in non-traditional ways, whether that's crowd-funding or developing a hand-held DNA sequencing device for under $1,000.”
Marcus Lovell Smith, president and CEO for Diagnostics for All, agrees that there is little sense in thinking of crowd-funding as being any more than a niche source of funds for the high-tech resource-intensive projects we’re describing, acknowledging that the benefits of such a campaign may be more subtle.
“I would love to do some,” he says. “Haven’t done it. Probably should. And we should see if there’s an appetite for the things that we do.”
Regardless of whether QuantuMDx reaches its target, O’Halloran indicated that he doesn’t expect this will be the last we hear of this approach.
“There has been a lot of interest in a biotech such as us going for crowd-funding,” he waxes. “I think we’ll see some more brave biotech entrepreneurs following our footsteps into the crowd-funding arena over the next year.”