Breakthroughs Blog: NTDs

A Phase 2 trial in The Gambia found that a vaccine for enterotoxigenic Escherichia coli (ETEC), a leading cause of diarrheal disease in children in low-income countries, was safe and effective in children between 6 and 18 months old. Cases of ETEC are expected to increase in the coming years due to climate change, and the vaccine under study, ETVAX, the most advanced of the several ETEC vaccines in the pipeline, could help reduce illness and death, lower health care costs, and curb the growing threat of antimicrobial resistance. The vaccine will now advance to a large multicountry Phase 3 trial for further evaluation. A research team at the University of Buffalo has developed an inhalable drug-delivery system for treating tuberculosis (TB), which could reduce the frequency of dosing and lessen side effects. Standard treatment for TB can be lengthy and require multiple drugs, with unpleasant side effects, leading some patients to stop treatment— contributing to the emergence of drug-resistant TB. The new approach involves an inhalable nanoparticle system that modulates the immune system and carries rifampin, a common TB drug, directly to the lungs, where TB bacteria primarily reside. This targeted method contrasts with the pill formulation of rifampin, which, when taken orally, only delivers limited amounts of the drugs to lung tissue. Further studies will explore whether the nanoparticle system can deliver combination treatments, which are the cornerstone of TB treatment, and whether the system can be adapted to address other lung diseases. Ghana recently became the first-ever country to approve a new single-dose combination treatment for soil-transmitted helminths, which cause parasitic infections that affect millions in endemic regions in Africa. The regimen is as safe as the standard drug used in mass deworming campaigns and demonstrates improved efficacy against whipworms, which are often resistant to the single-drug treatment. The medicine is also fruit-flavored, fast-dissolving, and incorporates a novel age-based dosing strategy, making it suitable for children. Administering the two drugs incorporated in the combination treatment previously required between two and six pills per person. 

A two-year citywide experiment in Singapore found that releasing Wolbachia-infected mosquitoes was effective at reducing mosquito numbers and dengue transmission in the densely populated city, supporting their use as a complement to existing vector control methods and vaccines to control transmission of dengue and other mosquito-borne diseases. Wolbachia is a common type of bacteria found in insects that cannot make people or animals sick but can stop the dengue virus from replicating inside the Aedes aegypti mosquitoes that spread dengue and other viruses, reducing mosquito populations and disease transmission. The researchers divided the city into clusters, releasing sterile infected male mosquitoes in some areas while leaving other areas untouched. They found that where the infected mosquitoes were released, mosquito numbers fell sharply, and people living there were about 70 percent less likely to develop symptomatic dengue after a few months of exposure. A Phase 4 randomized controlled trial has provided further evidence of the safety and efficacy of shortened regimens of preventive tuberculosis (TB), which could help improve uptake and completion rates. The trial, conducted in Brazil, tested one- and three-month regimens of isoniazid and rifapentine, much shorter than the current standard regimen of isoniazid, which lasts six to nine months and has seen poor uptake and completion rates. Additional studies are needed to ensure safety and acceptability across diverse populations. A Stanford University research team has developed an affordable, battery/solar-operated microscope called Octopi that uses artificial intelligence (AI) to automatically diagnose malaria in blood samples in minutes, which could greatly improve access to early and accurate diagnosis in low-resource settings. Confirmatory malaria diagnosis is currently done through a long, technical process carried out manually by lab technicians. The team also developed a complementary tool to automate and standardize the process of preparing blood samples, which is open source, requires no electricity, and is cheap. 

Last week, Moderna announced that it has received an award from the Coalition for Epidemic Preparedness Innovations (CEPI) for up to $54.3 million to support ongoing development of its bird flu mRNA vaccine candidate, after US government backing was cancelled earlier this year. There are currently no vaccines available specifically for bird flu, as the virus continues its worrying spread among animal populations in the United States and globally. A vaccine, especially one using the mRNA platform known for its speed and adaptability, could play a crucial role in curbing a future outbreak in humans with pandemic potential.  A research team led by the Australian Peter Doherty Institute for Infection and Immunity has identified a tool that can detect emerging hotspots for Buruli ulcer years before human infections occur, as the serious bacterial skin infection continues to spread across Australia and endures in other regions around the world. The infection has a long and variable incubation period, making it hard to identify when and where patients were exposed. The researchers tracked the excreta of possums, who have small ranges, making the presence of the bacterium that cause the infection in their excreta a likely sign that it is present locally. Then, they used DNA sequencing to compare the bacterial genomes of possum-derived and human-derived infections, finding where they overlapped to identify areas where human infections could occur. The method aims to allow public health authorities to implement targeted interventions early on, far before human cases occur. Two new studies looking at preventive RSV vaccines and drugs found that that their effectiveness waned over time, suggesting that boosters may be needed to ensure long-lasting protection, as RSV continues to pose a growing seasonal challenge, especially for older adults and infants. The first study found that one dose of the Abrysvo RSV vaccine was highly effective at preventing infections and reducing hospital, emergency department, and intensive care unit admissions in US veterans 60 and older, but this protection decreased over time, with the reductions most notable for immunocompromised individuals. A second study found that the long-acting monoclonal antibody nirsevimab was highly effective in hospitalized European children two years or younger for one season, but after that, protection waned. Both studies demonstrate the real-world impact of these crucial tools and suggest that boosters could be implemented to ensure long-lasting protection, especially for higher-risk individuals. 

A Phase 1 clinical trial testing an experimental monoclonal antibody for malaria found that the highest dose of the treatment studied was highly effective in preventing malaria. Researchers from the University of Maryland, Sanaria, the Vital Narrative consultancy, and the Gates Medical Research Institute tested the monoclonal antibody, MAM01, in 37 adults who had never been exposed to malaria, who received either a single dose of varying sizes or a placebo, and then were infected by the bites of infected mosquitoes. None of the three recipients who received the highest dose had malaria parasites in their blood after infection. The monoclonal antibody could prove to be an important treatment option that provides immediate, high-level, and long-lasting protection with just one doseA Japanese research team has isolated natural compounds from marine sponges that demonstrate an ability to kill parasites that cause leishmaniasis, which affects approximately 12 million people around the world. Current treatments are highly toxic, cause serious side effects, and can be prohibitively expensive, leaving patients, particularly in low-income communities, which face a disproportionate burden of leishmaniasis, unable to access or complete treatment. Drug resistance is also complicating leishmaniasis treatment efforts. These findings could guide research into new treatment approaches and could potentially also be applied to other protozoan diseases like Chagas disease and African sleeping sickness. A new CRISPR-based RNA test could help track the parasites that spread Human African trypanosomiasis, or sleeping sickness, which affects around 500 people per year and many more livestock animals. The test can identify parasite species living in an animal’s blood, helping public health workers carry out targeted treatment of infected animals and prevent transmission to humans. This One Health approach to zoonotic or parasitic diseases could also be rolled out to address other diseases, such as Chagas disease or leishmaniasis.