Research Roundup: Schistosomiasis drug resistance, a nanotechnology vaccine platform, and adjusting doses to bolster the yellow fever vaccine supply

The House Energy & Commerce Committee recently passed an amendment—attached to an unrelated bill—that would add requirements for eligibility to the Tropical Disease Priority Review Voucher (PRV) program at the US Food and Drug Administration (FDA). The PRV program, established by Congress in 2007, is intended to incentivize research and development (R&D) for drugs for which there is a critical need but a limited market opportunity. Under the program, the regulatory sponsor of an approved drug for a tropical or rare pediatric disease is awarded a voucher which expedites FDA review of a future product by four months. These vouchers enable companies to enter the market sooner, and several have been sold between companies for up to US$350 million. Of the three vouchers that have been awarded for tropical disease drugs, two were awarded to companies that weren’t actually involved in the drug’s development—they had merely acquired rights to the drug—and in one case, the drug was already approved by other regulatory authorities and available in 80 countries. The amendment, introduced by Congressman G.K. Butterfield (D-NC), would require the regulatory sponsor to demonstrate the need for the product (i.e., the global burden of the disease and demand for the product) and elucidate their plan to ensure access to the product. Vienna-based researchers have developed a vaccine against Toxic Shock Syndrome (TSS), a rare, life-threatening condition resulting from an extreme immune system response to a Staphylococcus infection. TSS is associated with the use of super absorbent tampons, and an estimated half of cases occur in menstruating women. In a phase 1 clinical trial, the vaccine candidate—which contains a detoxified strain of Staphylococcus—proved to be safe and successfully prompted an immune response. The vaccine will next be tested in a larger, phase 2 trial. The team anticipates the vaccine will last for five years and will be used to protect individuals with a compromised immune system who are at greater risk for TSS. Nature took an in-depth look at drug repositioning, in which a medicine developed to treat one disease or condition is used to treat another. Drug repositioning is not a new concept; leading drugs against HIV and AIDS and erectile dysfunction were once intended to treat cancer and angina, respectively. However, the practice is becoming more common. Since 2011, the number of journal articles published on repurposed drugs has increased sixfold to an average of 30 per month and each year three to four new companies focused solely on the practice are established. Generic medicines are a common target, however, there are also many drugs that have passed phase 1 or clinical trials, proving to be safe for use in humans, but that did not have the intended effect. This approach makes drug development cheaper and faster, as phase 1 trials can often be skipped. Repositioning a drug costs $300 million and takes 6.5 years, compared to $2 to 3 billion and 13 to 15 years when starting from scratch. However, phase 1 trials may still be needed if the drug needs to be delivered in a different way or if a different dose is needed. Additionally, many pharmaceutical companies have massive, untapped compound libraries and new technology and software have made it easier to discover ways in which distinct conditions manifest similarly on a molecular level, which allows them to better identify promising compounds to screen for a given condition or disease.

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.