Breakthroughs Blog: Diagnostics

The US National Institutes of Health (NIH) announced the Antimicrobial Resistance Diagnostic Challenge last week, a competition which will award US$20 million for the development of rapid, point-of-care diagnostics to combat antimicrobial resistance. The competition will be funded by NIH's National Institute of Allergy and Infectious Diseases and the US Department of Health and Human Services’ Biomedical Advanced Research and Development Authority, while the US Centers for Disease Control and Prevention and the US Food and Drug Administration will provide scientific and regulatory expertise. Eligible diagnostics are those that either test for drug-resistant bacteria or differentiate between viral and bacterial infections, critical tools to reduce ineffective and unnecessary antibiotic prescriptions. The recently launched Coalition for Epidemic Preparedness Innovations (CEPI) will fund early stage human clinical trials and stockpile vaccine candidates for the viruses most likely to cause the next major epidemic. CEPI will collaborate with product developers and the World Health Organization (WHO) to facilitate regulatory review of vaccine candidates and to ensure that large scale clinical trials can be rapidly rolled out in the case of an outbreak. Eligible vaccine candidates will target viruses identified by the WHO as the greatest threats, including Crimean Congo hemorrhagic fever, Ebola and Marburg, Lassa fever, Rift Valley fever, Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS), and Nipah virus. The coalition was formed by the governments of India and Norway, philanthropic organizations the Wellcome Trust and the Bill & Melinda Gates Foundation, and the World Economic Forum and will be housed at the Norwegian Institute for Public Health in Oslo. The International Vaccine Institute (IVI) is partnering with Xiamen Innovax Biotech Co., Ltd. (Innovax) to expand access to the world’s first and only vaccine against Hepatitis E—a viral disease that causes 20 million infections and results in 70,000 deaths and 3,000 stillbirths each year. The vaccine, Hecolin®, was developed by Innovax and is only licensed for use in China. The Gates Foundation will support an assessment of the vaccine to determine its eligibility for WHO prequalification—a process that evaluates the safety, efficacy, and quality of a specific health tool produced by a specific manufacturer and that enables the product to be purchased by United Nations agencies. Hecolin® offered complete protection against hepatitis E in a phase 3 clinical trial with more than 100,000 participants. Pharmaceutical company Takeda has initiated a phase 3 clinical trial of its vaccine candidate against dengue fever, a mosquito-borne infection caused by four closely related viruses. Last year, pharmaceutical company Sanofi launched the world’s first dengue vaccine, however, new research suggests that the vaccine could actually increase the severity of infections in children who have never been exposed to dengue. This is due to antibody-dependent enhancement, in which protective antibodies against a virus (in this case, one strain of dengue virus) can actually help related viruses (the other three strains of dengue virus) attack human cells. Consequently, the antibodies produced by children receiving the vaccine could actually exacerbate the symptoms of future infections. In phase 1 and 2 trials, Takeda’s vaccine candidate appeared to be safe and resulted in the production of antibodies against all four strains of the virus. For its phase 3 trial, Takeda plans to enroll 20,000 children in dengue-endemic nations in Latin America and Asia. The trial will evaluate safety and efficacy against all four strains of dengue and in children with and without prior exposure to the virus.

Reducing unnecessary antibiotic use is widely considered a priority action in combating the spread of antimicrobial resistance. In the United States, one-third of antibiotic prescriptions are unnecessary and each year, there are 27 million gratuitous prescriptions for respiratory infections alone. Rapid, point-of-care diagnostics that can discern if an infection is bacterial could significantly reduce this practice, preventing antibiotic prescriptions for viral, parasitic, or fungal infections. There are now several tests in the pipeline which evaluate the level of C-reactive protein (CRP) in the bloodstream, a molecule associated with inflammation. CRP levels increase significantly in response to bacterial infections, but only slightly in response to viral infections. Not only have several of these tests proven reliable, but new research conducted by the Oxford University Clinical Research Unit in Vietnam indicates that such a test can successfully decrease antibiotic prescriptions for respiratory infections in low-resource settings. The study monitored antibiotic use for 2,000 patients at ten primary health centers, and use of the test reduced prescriptions from 78 to 64 percent, without impacting clinical recovery or patient satisfaction rates. Scientists have identified a compound that shows promise in treating three different parasitic diseases—Chagas disease, sleeping sickness, and leishmaniasis—that effect 20 million people and result in 50,000 deaths each year. The three diseases are caused by distinct parasites and transmitted by different vectors. Chagas disease results in cardiac complications, sleeping sickness causes neurological symptoms, and leishmaniasis manifests as skin sores and liver and/or spleen damage. Existing treatments are toxic, expensive, and difficult to administer in low-resource settings. The compound—GNF6702—was developed by pharmaceutical company Novartis and discovered after screening 3 million molecules in the company’s compound library. The molecule was then modified, resulting in a drug with 20 times the original potency. The compound targets proteasome—which breaks down waste—in all three parasites, but does not have the same effect in mammal cells. The drug has proven effective in mice, and will undergo additional safety tests before the initiation of human clinical trials.  The US Agency for International Development (USAID) announced last week the initial winners of its Combating Zika and Future Threats Grand Challenge, through which the agency will be providing more than US$15 million for the development and introduction of 21 innovative tools and interventions. In just two months, USAID received and reviewed nearly 900 applications, addressing various parts of outbreak prevention, detection, and control, including vector control, personal and household protection, vector and disease surveillance, community engagement, and diagnostic innovations. The winners include an electric force field to repel mosquitoes; a flip phone–based app that can distinguish between mosquito species, enabling crowdsourced vector surveillance; insecticide-treated sandals; and a human-scented mosquito trap. The agency will announce additional winners in the next month and will invest up to $30 million total.

Earlier this year, the World Health Organization (WHO) declared the outbreak of Zika in Latin America a Public Health Emergency of International Concern. The virus, spread by the Aedes aegypti mosquito, was once considered innocuous, causing a mild illness and lasting for only a handful of days. However, the virus has since been linked to devastating birth defects and neurological complications and has spread to more than 60 countries. The virus’s virulence took the research community by storm: although it was discovered in 1947, only 25 scientific papers were published on the topic prior to the current outbreak. As the scientific community learns more about the virus and the disease, the need for tools to prevent, detect, and treat it has become undeniable. On February 22, US President Barack Obama submitted a request to Congress for US$1.9 billion in emergency funding to combat the virus, a critical move, as the US government is unrivaled as the largest funder of global health research and development (R&D). However, 146 days later, Congress has yet to reach a deal, and the US agencies leading the fight against Zika are running out of money. In the meantime, these agencies have made impressive strides in advancing Zika R&D using limited funding and leveraging cross-sector partnerships. An unprecedented number of private-sector partners have also entered the hunt for Zika countermeasures, building out a robust pipeline in record time. Below, we highlight the most promising vaccine, drug, and diagnostic candidates as well as vector control approaches. Vaccines There are currently more than 35 Zika vaccine projects underway, and at least 3 have completed successful animal trials. Inovio Pharmaceuticals and GeneOne Life Sciences partnered to develop a DNA-based vaccine, using a unique delivery approach—electroporation—in which a device is applied to the injection site, sending out electrical pulses that enhance the vaccine’s ability to enter human cells. The vaccine successfully prompted an immune response, including the production of protective antibodies, in both mice and monkeys. In late June, the experimental vaccine became the first to be approved for human clinical trials by the US Food and Drug Administration (FDA). The phase 1 trial, which will enroll 40 healthy adults, is intended to evaluate the safety and tolerability; however, the team will also monitor its ability to induce an immune response. Meanwhile, two more vaccine candidates have proven effective in mice. The candidates include a DNA-based vaccine and one composed of an inactivated version of the Zika virus, the first supported by the US National Institutes of Health (NIH) and the second developed by the US Walter Reed Army Institute of Research. The latter will be tested in phase 1 clinical trials by the US National Institute of Allergy and Infectious Diseases and then transferred to French pharmaceutical company Sanofi for further clinical development. Sanofi is also working on a vaccine of its own; however, it won’t enter clinical trials until 2017. After several months of feasibility studies, British pharmaceutical company GlaxoSmithKline has announced that it will be partnering with the NIH to test its RNA-based vaccine in animals. To date, no DNA or RNA vaccines have been approved for use in humans, although they are often called the future of vaccines. Drugs Due to the dearth of knowledge about the virus and the difficulty of conducting clinical trials and using novel drugs in pregnant women—a key target population for Zika control—the WHO has stated, “It is unlikely at this stage that therapeutics will constitute a priority activity.” However, efforts are underway, both to discover novel treatments and to repurpose existing medicines. Australian biotech company Biotron announced recently that two compounds in their library have proven effective against Zika in test tubes. They will continue to conduct laboratory tests to better assess the safety and efficacy of the compounds in humans. Researchers at the US National Center for Advancing Translational Sciences are screening their compound library—with half a million entities— and have identified a novel drug, which is safe for use in humans and currently in clinical trials for cancer, that prevented the virus from killing progenitor cells, which play a critical role in the neurological system and fetal development. Researchers at the University of California, San Diego are embarking on an ambitious study to virtually screen more than 20 million compounds against the virus. The program—OpenZika—uses a research collaboration platform to harness the power of volunteers’ computers and smartphones. Participants download the software, and when their computer or phone is inactive, it runs calculations to predict how a compound will interact with the virus in the lab. Researchers are also looking at repurposing existing drugs as Zika treatments. Chloroquine—which both prevents and treats malaria—has successfully protected against Zika virus in vitro. A team at Katholieke Universiteit Leuven has identified an experimental treatment for hepatitis C that delayed the manifestation of Zika-related symptoms in mice. And scientists at the University of California, San Francisco reported that the antibiotic azithromycin—which has long been used in pregnant women—blocked the virus from multiplying in petri dishes. Diagnostics As of March, more than 30 diagnostics for the virus were under development, and the FDA has sanctioned the use of five tests—four that detect current infection and one to assess previous exposure—under its Emergency Use Authorization program. However, rapid, point-of-care diagnostics are desperately needed. Eighty percent of cases are asymptomatic, and initial symptoms—fever, rash, joint pain—are nonspecific. Thus, early and accurate diagnosis is critical to ensure appropriate treatment. A team of Harvard University and Massachusetts Institute of Technology researchers have designed a paper-based test that can diagnose cases within a few hours. The device is appropriate for low-resource settings: it’s cheap, it can be stored or shipped at room temperature, and the results are easy to interpret. The tool contains miniscule sensors that change color in the presence of a specific genetic sequence. To ensure accurate detection of the virus, the team developed sensors that can detect 24 different genetic sequences found in the Zika genome. The device has been tested using samples from infected monkeys and has proven to be effective at detecting even low quantities of the virus. Although the results are easy to read—a positive sample turns the strip purple—the team has also created a simple electronic reader that determines the quantity of the virus in the sample. Vector Control As vaccines, drugs, and diagnostics against the virus inch their way through the R&D pipeline, health officials are ramping up vector control efforts against the Aedes aegypti mosquito. New techniques are also underway, and the FDA is currently accepting public comment on a proposal to expand testing of genetically engineered mosquitoes. The mosquitoes mate with the local population, resulting in offspring that die before reaching adulthood and are consequently not able to spread diseases. A trial of the mosquitoes in Brazil led to an 82 percent decrease in the Aedes aegypti population in just nine months. Scientists are using innocuous bacteria and fungi to combat the spread of Zika. Male mosquitoes infected with the Wolbachia bacteria do not produce viable offspring, and tests across the United States have reduced the population of the closely related Aedes albopictus mosquito by an estimated 70 percent. Meanwhile, the Metarhizium brunneum fungus is used as a natural pesticide, killing mosquito larvae. Meanwhile, in North Hempstead, New York, bats have been enlisted in the fight against Zika. The city is building and hanging bat houses in parks to attract the animals, as they can eat more than 1,000 mosquitoes in an hour.

Researchers at the Durham University in the United Kingdom have received a US$100,000 grant from the Bill & Melinda Gates Foundation to test the feasibility of training dogs to detect malaria. Dogs have been trained to use their keen sense of smell to detect other diseases, including certain cancers, and studies suggest that malaria infection causes a distinct odor, and that unique chemicals can be found on the breath of patients. The team plans to recruit 400 children in the Gambia, including many who are currently infected with malaria. The children will wear nylon socks for 24 hours, which will then be used to train the dogs to identify malaria based on odors in the sweat and skin. If successful, this approach to malaria testing would be quick and cheap, and would not require any equipment or a laboratory setting. A new, commercially-available diagnostic can predict premature births, a critical tool as half of all preterm births occur in women without known risk factors. Between 2011 and 2013, the Utah-based Sera Prognostics enrolled more than 5,500 pregnant women at 11 sites across the United States, and confirmed that the quantity of two proteins in the blood can indicate risk for preterm birth. The test can be administered at 19 or 20 weeks into the pregnancy; pregnancy normally lasts 40 weeks and delivery before 37 weeks is considered preterm. The test—PreTRM®—tells a woman her percentage risk, and currently costs $945, however, Sera Prognostics is working with the Bill & Melinda Gates Foundation to develop tools more suitable for low-income countries. Startup NextGen Jane is developing a “smart tampon” that would collect menstrual blood each month and test for a range of diseases and conditions, including sexually transmitted infections, endometriosis, polycystic ovarian syndrome, uterine fibroids, cervical cancer, and more. Many of these conditions are asymptomatic, and consequently go undetected until significant damage has been done. The team at NextGen Jane has a working prototype—a device that siphons menstrual blood from tampons—and is conducting clinical trials for several of the diagnostics themselves, which identify biomarkers for different conditions in menstrual blood. The tool will connect to a database, allowing women to analyze the data and track their reproductive health over time. The team anticipates having a complete product—combined diagnostics and the delivery mechanism—within the next year, which will be commercially available within three to four years.