DMID Support Helps to Yield Successful Medical Advances
Medical interventions take years of scientific research and are often achieved through multiple partnerships and collaborations. The Division of Microbiology and Infectious Diseases (DMID) supports research and provides resources for all stages of product development, partnering with public and private institutions to move advances through the product development pipeline. The results are research discoveries that are transforming the prevention, diagnosis, and treatment of infectious diseases. The DMID scientific success showcase highlights just a few of these achievements.
NIAID supports research to prevent, control and treat infectious diseases.
Intravenous Fosfomycin to Treat Multidrug-Resistant Infections
Since the introduction of penicillin in the 1940s, a complex array of factors has led to an era in which some bacterial infections no longer respond to any approved antibiotics. The Centers for Disease Control and Prevention estimate that antibiotic-resistant bacteria cause at least 23,000 deaths and two million illnesses annually in the U.S. alone.
To improve therapeutic options for resistant infections, NIAID provided support to Zavante Therapeutics, Inc. for the clinical development of the intravenous (IV) form of the antibiotic fosfomycin (Zolyd™). Fosfomycin is a broad-spectrum antibiotic active against many Gram-positive and Gram-negative bacteria, including multi-drug resistant strains. However, unlike in Europe, where both oral and IV formulations are approved, this therapeutic is only available in oral form in the U.S. IV delivery allows the antibiotic to be delivered directly into the bloodstream, acting much faster than the oral form and reaching the concentrations needed to treat complicated hospital-acquired infections. A NIAID-supported phase I clinical trial demonstrated the safety of IV fosfomycin in healthy adults and provided insight into the concentrations of fosfomycin reached in blood and urine using different doses of oral and IV fosfomycin.
Following the success of the phase I trial, Zavante Therapeutics sponsored a phase II/III clinical trial evaluating the efficacy of IV fosfomycin in treating complicated urinary tract infections (cUTI). The study compared IV fosfomycin against the standard treatment (piperacillin/tazobactam) and found that IV fosfomycin was safe and worked equally as well in these patients. The U.S. Food and Drug Administration granted Fast Track designation and Qualified Infectious Disease Product designation for the investigation of fosfomycin for cUTI, hospital-acquired bacterial pneumonia (HABP), and ventilator-associated bacterial pneumonia (VABP), among others. Animal experiments performed through NIAID's Preclinical Services program showed that fosfomycin may be useful for treating lung infections caused by multidrug-resistant bacteria. NIAID is now supporting a phase I trial to establish the right dosage for the use of this important investigational antibiotic in patients with HABP and VABP.
Vancomycin-resistant enterococci (VRE) can cause complicated urinary tract infections (cUTIs). Fosfomycin has been used to successfully treat UTIs caused by VRE.
Rapid Diagnostics to Combat Antimicrobial Resistance
The development of rapid, point-of-care diagnostics that can specifically identify the bacteria or virus causing an infection is an important step in combatting antibiotic resistance. Currently, broad spectrum antibiotics, which target a wide range of bacteria, are often prescribed when a diagnosis cannot be made prior to starting treatment. Diagnostics that identify the cause of an infection, as well as the susceptibility of that pathogen to specific antibiotics, can inform appropriate treatment, promote antibiotic stewardship, and ultimately, help fight antibiotic resistance.
NIAID has supported and continues to support a number of diagnostics to combat antibiotic resistance, including multiplex platforms such as the FilmArray Blood Culture Identification Panel by BioFire Diagnostics LLC, an affiliate of Biomérieux. Through small business grants and partnerships, NIAID supported the development of this polymerase chain reaction (PCR)-based system, which has been cleared by the Food and Drug Administration, to simultaneously detect several pathogens in patient samples in around one hour. This panel tests for 24 Gram-positive bacteria, Gram-negative bacteria, and yeast microbes that cause bloodstream infections (sepsis).
Recently, NIAID provided support for novel approaches to diagnostics, including using digital imaging to rapidly detect Methicillin-resistant Staphylococcus aureus (MRSA) and using a technique known as surface-enhanced Raman spectroscopy as a diagnostic platform to detect bacteria and antibiotic susceptibility. Ongoing work from the NIAID-supported Antibacterial Resistance Leadership Group (ARLG) includes developing and validating new diagnostics and evaluating the effectiveness of existing platforms. Through the RADICAL study, ARLG investigators are exploring the potential of host biomarker signatures to differentiate between viral and bacterial respiratory infections.
Future research will continue to focus on diagnostic development. In 2015, NIAID awarded funds for nine projects to develop diagnostics to rapidly detect antimicrobial-resistant bacteria, including pathogens that frequently cause infections in health care settings.
Scanning electron micrograph of methicillin-resistant Staphylococcus aureus bacteria (yellow, round items) killing and escaping from a human white cell.
Designer Flu Proteins: A New Approach to Universal Influenza Vaccines
The influenza virus causes annual epidemics, which result in millions of cases of severe illness worldwide. High-risk groups, including pregnant women, the very young or elderly, and chronically ill individuals, are more likely to experience complications from influenza infection, such as pneumonia or bronchitis. Current influenza virus vaccines are effective, but they have to be reformulated and administered annually to target the influenza virus strains predicted to circulate each year.
To address these issues, NIAID is supporting research to promote the development of universal influenza vaccines, which would provide broader protection against multiple strains of influenza viruses.
Influenza vaccines induce antibodies that target the viral protein hemagglutinin (HA), which is important for virus entry into host cells. This protein is made up of a head and a stalk domain. Most antibodies elicited by vaccines target the immunodominant head domain, but some antibodies do target the stalk. The head domain can vary widely between different virus strains and is subject to genetic changes with time, which is why new vaccines are required annually. However, the stalk domain of the HA protein is more constant, or conserved.
NIAID has been supporting a universal vaccine strategy which uses vaccine constructs that are made of combinations of conserved HA stalk domains with variable HA head domains derived from different virus strains. Sequential vaccination with these constructs allows an enhanced antibody response to form against the conserved stalk; these antibodies have been shown to provide broad protection against many influenza virus strains.
NIAID has provided support for this universal influenza vaccine strategy, allowing the work to advance from basic research and proof-of-concept studies in animals through preclinical development. This work has facilitated major advances in the development of a universal influenza vaccine.
3D print of hemagglutinin (HA), one of the proteins found on the surface of influenza virus that enables the virus to infect human cells.
Rotavirus Vaccine Mix and Match Study
The severe diarrhea, fever, abdominal pain, and dehydration associated with rotavirus disease in young children can be prevented by vaccination. There are currently two rotavirus vaccines licensed for infants in the United States, Rotarix and RotaTeq, which require 2 or 3 doses, accordingly.
In practice, children may receive either Rotarix or RotaTeq, or they may receive a mixture of the two vaccine products. This happens when children change health care providers or when their providers change vaccine stocks between doses. NIAID-supported researchers conducted a clinical trial to see if switching from one vaccine product to another works as well as using the same product for all of the doses. In this trial, children received either RotaTeq or Rotarix for the first dose, followed by 5 different combinations of the 2 vaccines to complete the vaccine series.
The researchers found that immunization with these different combinations of the 2 vaccines was as effective as using one vaccine product for the vaccination series in generating an immune response against rotavirus. These findings provide needed evidence to health care providers administering rotavirus vaccination to infants and support the effectiveness of using a mixed rotavirus vaccine schedule.
A 6-month-old girl receives her oral rotavirus vaccine.
Credit: CDC/Andre Berro, Division of Global Migration and Quarantine
Rapid, Accurate Diagnostics for Ebola
Early symptoms of Ebola virus disease (EVD), including fever, muscle pain, headache, and diarrhea, are often indistinguishable from symptoms of other diseases. However, EVD can progress to impaired kidney and liver function and internal and external bleeding. Because of the severity and high fatality rate, rapid and accurate diagnosis of Ebola infection is critical.
NIAID has supported the development of improved diagnostics to detect Ebola virus infection, including those that can provide rapid identification and can be deployed at the point-of-care where Ebola outbreaks occur. Three of these diagnostics were granted Emergency Use Authorization (EUA) by the Food and Drug Administration for detection of the Ebola Zaire strain during the 2014 West Africa outbreak.
Two of these tests, the FilmArray Biothreat-E test, developed by BioFire Defense LLC, and the Xpert Ebola Test, manufactured by Cepheid, are polymerase chain reaction (PCR)-based tests that can detect viral nucleic acid in patient samples in less than two hours.
NIAID has provided support for FilmArray since 2005, with an initial focus on respiratory pathogen detection. From 2009 - 2012, NIAID supported the development of a biothreat panel, which included an Ebola diagnostic test. For the Xpert technology platform, NIAID initially funded basic science research for technology required for this diagnostic, supported the development of the Xpert for use as a diagnostic for tuberculosis, and provided funds to support an Xpert diagnostic for Ebola. The Biothreat E-test and Xpert Ebola Test received EUA in October 2014 and March 2015, respectively.
The third test, ReEBOV Antigen Rapid Test Kit developed by Corgenix, received an EUA in February 2015. This test, which can provide results within 15 minutes, is based on direct detection of an Ebola protein, rather than amplification of nucleic acids. Since 2010, NIAID has provided grant support to Corgenix for the development, preclinical testing, and manufacturing of diagnostics for Ebola and other filoviruses. Recently, diagnostics for simultaneous detection of Lassa fever and malaria were added to this project, to distinguish these diseases from EVD, all of which share early clinical symptoms.
NIAID also is advancing development of other types of diagnostics, including those using novel technologies, such as microfluidics, optofluidics, and nanophotonics, which are capable of detecting an array of viruses, including Ebola viruses.
Colorized scanning electron micrograph of Ebola virus particles (red) in extracellular space between infected African green monkey kidney cells.
A New Treatment for Pediatric Influenza
Children, especially those under 5 years of age, are at risk of serious complications resulting from influenza infection. Until recently, however, pediatricians had limited options for treating flu in this highly vulnerable population. Most therapeutics are not formulated for pediatric use, and many are no longer effective due to influenza's rapidly emerging drug resistance. While a drug called oseltamivir, or Tamiflu, provided a potentially effective treatment option, it had not been tested or approved for infants by the FDA. In order to prepare for a potential influenza pandemic, it was important to assess the safety and effectiveness of oseltamivir in young children and to gain FDA approval.
To address this need, NIAID funded three separate studies. The first was a retrospective chart review that assessed any neurological symptoms associated with the use of influenza drugs in children under the age of 1. No neurologic signals were observed, and this result allowed researchers to proceed with the second trial. This trial was conducted to determine the appropriate dosage of oseltamivir in children of various age groups. A third study was conducted during the 2009 H1N1 influenza outbreak. Following exposure to a nurse with influenza, a neonatal intensive care unit (NICU) began treating infants with oseltamivir, and a study was developed to assess whether the dose given was adequate. The results of this study currently provide the only available data on using oseltamivir to treat influenza in the NICU.
These research studies showed that oseltamivir is a safe and effective influenza treatment for children and infants. Based on these results, the FDA expanded the approved use of oseltamivir to children as young as 2 weeks old. As the only product approved to treat the flu in children younger than 1 year old, oseltamivir is an essential new tool in our fight against influenza.
Novel Therapeutic for Malaria: DSM265
Malaria is an infectious disease caused by multiple species of the parasite Plasmodium. Of the four malaria parasites that infect people, P. falciparum is the most deadly. Half of the world's population is at risk for malaria. In 2012, an estimated 207 million people contracted the disease, claiming 627,000 lives, mostly infants, young children, and pregnant women in Africa (WHO). With the emergence and spread of drug-resistant malaria, limited treatment options remain for this once-curable disease. New antimalarial drugs are needed to address the growing challenge of drug resistance.
NIAID-supported scientists at the University of Texas Southwestern Medical Center and University of Washington identified an enzyme-known as dihydroorotate dehydrogenase (DHODH)-that is critical to the growth of Plasmodium parasites. With NIAID support, the public-private partnership Medicines for Malaria Venture (MMV) identified a drug candidate targeting this enzyme. This novel antimalarial drug, DSM265, is part of a group of compounds known as DHODH inhibitors, named after their mechanism of action that halts the enzyme's activity.
NIAID preclinical services supported animal safety and toxicity studies as well as other early testing. When tested in mouse models, DSM265 was found to be effective against drug-sensitive and drug-resistant strains of P. falciparum. With NIAID support, scientists are evaluating other DHODH inhibitors as additional drug candidates.
MMV named the discovery and evaluation of DHODH inhibitors as their Project of the Year 2010 .
In 2013, MMV initiated the first clinical trials evaluating the safety, tolerability, and pharmacokinetic properties of DSM265. As part of this study, the effect of food intake on the drug's absorption was assessed. Furthermore, MMV explored the potential of DSM265 as single dose treatment for malaria. Future studies may also look at whether DSM265 could be used to prevent the disease.
3-D structure of DSM 265.
Credit: University of Texas Southwestern Med Center/Margaret A. Phillips, Ph.D.
Novel Therapeutic for Tuberculosis: SQ109
Treating TB can be difficult and complex. While most patients with drug-sensitive TB can be cured with a combination of antibiotics that have to be taken for 6 to 12 months, current medications are becoming less effective against the disease as the problem of drug resistance grows. New antibiotics and treatment regimens for TB are urgently needed.
In 1999, NIAID researchers discovered a novel antibiotic that later became known as SQ109. NIAID and the National Cancer Institute provided grants and preclinical services to Sequella, Inc., to further develop the drug. NIAID-funded contractors conducted both preclinical and clinical testing of SQ109, including drug interaction studies; safety and toxicity studies; tablet production; and Phase IB/IC clinical trials evaluating safety, tolerability, and pharmacokinetics.
These studies showed that SQ109 is effective against Mtb, including drug-resistant strains. Scientists also found that SQ109 boosts the activity of other TB drugs, suggesting that SQ109 could potentially be used in new treatment regimens against TB. SQ109 is a challenging drug to study since it is rapidly taken up into tissues and its blood concentrations cannot easily be measured. SQ109 is teaching us new and important lessons for TB drug discovery.
Several organizations are now supporting research to further characterize the safety and efficacy of SQ109 against drug-sensitive and multidrug-resistant TB all over the world. In addition, Sequella is evaluating the drug for possible therapeutic uses for other bacteria beyond Mtb, including Clostridium difficile and Helicobacter pylori.
Scanning electron micrograph of Mycobacterium tuberculosis bacteria, which cause TB.
A Novel Vaccine to Prevent Hepatitis C
An estimated 130-150 million people worldwide, including 2.7 million Americans, have chronic hepatitis C infections. The hepatitis C virus (HCV) causes irritation and inflammation of the liver and is a leading cause of cirrhosis and liver cancer. HCV is also a significant issue for HIV-infected individuals: it is estimated that approximately 25% of HIV-infected individuals are also infected with HCV. HCV is primarily transmitted via infected blood or body fluids, and needle sharing during intravenous drug use is the most common route of transmission in the United States. Currently, there is no licensed vaccine available to prevent this infection. In addition, the available medicines are costly and are neither effective for everyone, nor appropriate for people with certain preexisting medical conditions.
To address these issues, NIAID supported Okairos for the development of an HCV vaccine to prevent acute and chronic HCV infection. NIAID supported the manufacturing of the vaccine and toxicity testing. Currently, NIAID is supporting a Phase I/II clinical trial evaluating the safety, immune response, and initial efficacy of the vaccine in HCV-uninfected subjects. In 2013, an interim analysis showed that there were no concerns with safety or immunogenicity, and this assessment allowed the trial to continue to Phase II. This ongoing study is expected to enroll 540 uninfected adults who are at high risk of becoming infected with hepatitis C.
A vaccine for hepatitis C could significantly reduce the spread, symptoms, and long-term effects of this serious infection. Along with the NIAID-supported trial, ReiThera (formerly Okairos) conducted a Phase I clinical trial to study the safety and immune response of the candidate vaccine in chronically infected patients, as a first step to assess whether the same vaccine could help treat those who are already infected with HCV. While further study is needed, the current clinical trials are a significant step in the development of a safe and effective HCV vaccine.
Synthetic Tetracyclines To Combat Bacterial Infections
Tetracyclines are a group of broad-spectrum antibiotics used to treat several different types of bacterial infections, including those caused by both gram-positive and gram-negative bacteria. Unfortunately, many bacteria are developing resistance to this valuable treatment. To address this growing issue, NIAID is supporting the development of novel tetracyclines. Prepared using state-of-the-art chemistry developed by an NIAID-supported scientist at Harvard University, these synthetic compounds are not subject to existing tetracycline resistance mechanisms and therefore represent important new tools for the treatment of multidrug-resistant (MDR) bacterial infections.
NIAID grant support has enabled the chemical synthesis of over 2,000 novel tetracyclines, several of which are at various steps in the product development pathway. One new tetracycline called eravacycline (TP-434) was recently tested in a Phase III trial by Tetraphase Pharmaceuticals. In addition, NIAID is currently supporting a Phase I trial of TP-271, a novel tetracycline also developed by Tetraphase. These compounds are being developed for numerous bacterial indications, including community-acquired bacterial pneumonia, MDR gram-negative bacteria, methicillin-resistant Staphylococcus aureus (MRSA), Bacillus anthracis, Fransicella tularensis, and Yersinia pestis.
Colorized scanning electron micrograph of a white blood cell interacting with an antibiotic resistant strain of Staphylococcus aureus bacteria.
Using Existing Antibiotics to Treat Pneumonic Plague
Plague is caused by Yersinia pestis bacteria that infect the lungs and cause pneumonia. Pneumonic plague, the most deadly form of plague, can be spread from person to person. The U.S. Department of Homeland Security has designated plague as a potential bioterror threat.
Until recently, only a few antibiotics were licensed to treat plague. These drugs, approved more than 40 years ago, were indicated to treat plague in general, but not specifically for pneumonic plague.
In collaboration with the Food and Drug Administration (FDA), NIAID is supporting animal studies to determine whether newer antibiotics approved for other uses are also effective against pneumonic plague.
NIAID research services have been instrumental in advancing existing antibiotics toward new label indications. Beginning in 2003, preclinical services from DMID were used to establish the natural history of disease in nonhuman primates. Since then, NIAID has provided additional preclinical services to evaluate the pharmacokinetics, tolerability, and efficacy of widely available antibiotics in monkeys exposed to aerosolized (breathable) Y. pestis.
Data from NIAID-supported studies played a major role in FDA approval of the first drug for pneumonic plague. In April 2012, an FDA Advisory Committee unanimously recommended FDA approval of ciprofloxacin and levofloxacin as treatments for pneumonic plague. Soon afterwards, FDA approved levofloxacin to treat and prevent pneumonic plague, making it the first antibiotic approved under a regulatory approach known as the Animal Rule. The Animal Rule is a regulation enabling medical countermeasures to receive FDA approval based on effectiveness data in animals combined with safety and immune response data in humans. In February 2015, FDA approved ciprofloxacin for pneumonic plague.
This approach sets a precedent for FDA approval of other medical countermeasures under the Animal Rule (e.g., additional antibiotics for pneumonic plaque and other potential bioterror threats like Francisella tularensis). Approving existing antibiotics to treat pneumonic plague will enable the U.S. government to dispense and use such antibiotics from the Strategic National Stockpile to respond to public health emergencies. It will also inform and guide healthcare providers' treatment decisions in endemic areas and public health emergencies.
Scanning electron micrograph of Yersinia pestis, which causes bubonic plague, on proventricular spines of a Xenopsylla cheopis flea.
Vaccine Candidate Active Against Candida and Staphylococcus aureus: NDV-3
Currently, there are no licensed vaccines to prevent Candida or Staphylococcus aureus infections. With NIAID support, a vaccine candidate is being developed to protect against both of these infections.
Candida can cause fungal infections in humans. These infections, known as candidiasis, occur most frequently in individuals with risk factors such as weakened immune systems, certain medical conditions, and prior antibacterial use. In some cases, the fungus can escape from the gut to enter the bloodstream and cause more invasive disease known as candidemia, which is one of the most common bloodstream infections.
The bacterium S. aureus is one of the leading causes of healthcare-associated infections. Increased hospitalizations related to drug-resistant S. aureus infections have a significant human and economic impact, including increased mortality, longer hospital stays, and more complicated treatment.
A vaccine to prevent Candida and S. aureus infections could greatly benefit patients, especially those at high risk for infection such as people with weakened immune systems and individuals with high incidence of recurrent infections. NIAID has provided funding and support throughout basic research, discovery, and development of a vaccine candidate: NDV-3. In the early 1980s, NIAID funded studies at Harbor UCLA Medical Center to investigate how Candida adheres to and penetrates endothelial cells. This research led to the discovery of several adhesion proteins that conferred protection in mice. NDV-3 emerged as a lead vaccine candidate after years of evaluating candidates. NIAID preclinical services supported scale up, manufacture, and stability testing of this experimental Candida vaccine that also protects against S. aureus infection. In animal models, NDV-3 was found to be protective against several strains of S. aureus, including methicillin-resistant S. aureus (MRSA) strains. NDV-3 is the first vaccine candidate to provide protective efficacy across kingdoms, as it works against fungi and bacteria.
In Phase I clinical trials sponsored by NovaDigm Therapeutics, the cross-protective vaccine was well tolerated, safe, and induced strong antibody and T-cell responses. A Phase IB/IIA clinical trial is evaluating the ability of NDV-3 to prevent vaginal candidiasis in women with recurrent vulvovaginal candidiasis.
Fluorescent antibody stain revealing the oval budding yeast cells of Candida albicans fungal organisms.
Credit: CDC/Maxine Jalbert, Dr. Leo Kaufman
Second-Generation Smallpox Vaccine: Modified Vaccinia Ankara (MVA)
Smallpox is a disfiguring and deadly disease caused by Variola major. In 1980, the World Health Organization declared that smallpox had been eradicated worldwide. However, smallpox continues to concern public health officials as a potential biological weapon.
A vaccine known as Dryvax was used in smallpox eradication, and the United States has enough of its successor, Acam2000, on hand to vaccinate the population in case of a terrorist attack. However, people with weakened immune systems or skin conditions like atopic dermatitis are at increased risk for serious side effects from these vaccines.
NIAID recognized the need for a safer smallpox vaccine than Dryvax and ACAM2000 that could be used to protect patients with weakened immune systems, like those with HIV or cancer. With this goal, NIAID invested in the development of a second-generation vaccine using Modified Vaccinia Ankara (MVA)-a highly weakened vaccinia virus that does not replicate well in humans. MVA vaccine is being developed by Bavarian Nordic and holds promise as a safer alternative to Dryvax and ACAM2000 to make the nation safer in the event of a biological terrorist attack.
NIAID supported early advanced development work for this important vaccine. This included toxicology and efficacy studies to enable investigational new drug (IND) status and clinical trials in individuals infected with HIV and atopic dermatitis. Preclinical services such as studies on animal model development, natural history, virulence, and vaccine efficacy, contributed to the successful development of MVA. NIAID is supporting studies to enhance the stability of the vaccine, identify ways to decrease the amount of vaccine needed to provide protection, and explore MVA as a platform technology to provide protection against more than one disease.
In 2013, Canada and the European Union approved MVA (under the trade names IMVAMUNE® and IMVANEX®) for use in the general population, including people with weakened immune systems or atopic dermatitis. As of 2013, 20 million doses were delivered to the U.S. Strategic National Stockpile for use among these groups.
A transmission electron micrograph of smallpox viruses.
Credit: CDC/Dr. Fred Murphy
Anthim: A New Treatment for Inhalation Anthrax: Anthim
Inhalation anthrax is the deadliest form of infection caused by the bacteria Bacillus anthracis. When a person breathes in anthrax spores, infection begins in the chest lymph nodes and spreads throughout the body, causing severe breathing problems and shock. Immediate treatment is crucial to survival. Without treatment, only about 10 to 15 percent of patients with inhalation anthrax survive.
New treatment options for inhalation anthrax are needed. NIAID, in coordination with the HHS Biomedical Advanced Research and Development Authority (BARDA), supported preclinical and clinical research to develop several antibody-based therapeutics as anthrax antitoxins. One such product is Anthim, a human monoclonal antibody produced by Elusys Therapeutics, Inc. Anthim is intended to be used as an intravenous treatment for patients with inhalation anthrax and to prevent disease after exposure to inhaled anthrax spores.
NIAID supported the preclinical and clinical development of Anthim through several resources. Initially, NIAID worked with Elusys to develop a scalable process and produce a large quantity of a stable formulation of Anthim. The antibody was evaluated in animal models and demonstrated efficacy and, in small-scale clinical trials, was shown to be safe for humans. NIAID then advanced the development of Anthim by supporting the manufacture of several pilot lots. Following the success of these efforts, BARDA awarded Elusys an advanced development contract to support final development stages.
In 2016, the Food and Drug Administration approved Anthim for the treatment of inhalational anthrax in combination with appropriate antibacterial drugs, and for the prevention of inhalational anthrax when alternative therapies are not available or not appropriate.
Color-enhanced scanning electron micrograph shows inhalational anthrax; featured are rod-shaped bacilli (yellow) and an erythrocyte (red).
Credit: Arthur Friedlander
Fighting Fire With Fire: Healthy Bacteria May Help Combat Infection
There are many types of bacteria in and on the human body: some cause illness while others have positive effects like aiding our digestion or producing anti-inflammatory compounds. In the vagina, healthy bacteria are thought to provide a protective barrier against unwelcome pathogens, and researchers are currently working on defining the other roles these bacteria might play.
Although there is still much to be learned about healthy vaginal flora, we do know that an infection called bacterial vaginosis (BV) can occur when the normal balance of bacteria in the vagina is disrupted. Many women with BV do not have any symptoms, but some women experience pain, itching, odor, or burning of the vagina. Once diagnosed through laboratory tests, BV can be treated with antibiotics. Unfortunately, BV can recur in many women even after successful treatment. In addition, antibiotics can destroy healthy bacteria and therefore may eliminate the microbial defense system that healthy bacteria provide. This means that women with BV have an increased risk for contracting sexually transmitted infections, such as chlamydia, gonorrhea, and HIV. Pregnant women with BV are also at higher risk of preterm birth and other obstetric complications.
In order to reestablish healthy vaginal flora, an NIAID-supported research company called Osel has developed a novel product called LACTIN-V. LACTIN-V consists of a selected strain of Lactobacillus crispatus, one of the bacteria that protect the vagina from invading pathogens, that has been freeze-dried and formulated as a powder. When inserted into the vagina using a specially designed applicator, LACTIN-V helps reestablish the population of these beneficial bacteria. In early studies, LACTIN-V was shown to be safe and well-tolerated. Women who used LACTIN-V and became vaginally colonized with Lactobacillus crispatus had a lower rate of BV reinfection than those who didn't. LACTIN-V has also been shown to reduce the recurrence of urinary tract infections (UTIs) in women with a history of UTIs. Further clinical trials are currently underway and are helping to build toward FDA approval. If successful development continues, this new product could be a significant advance in BV treatment and in women's health overall.
Fluorescent photomicrograph of a human vaginal biopsy from a healthy individual showing Lactobacillus (rods stained green) adhering to epithelial cells (nuclei stained red).
Credit: Mark Pasmore and William Costerton/ Montana State University. Reproduced with permission from The Journal of Clinical Investigation.
A Novel Vaccine and Therapeutic for Hendra and Nipah Viruses
Hendra virus is an emerging virus that was first discovered in 1994 in Australian horses. Hendra occurs naturally in bats, which can transmit the virus to horses. All human cases of Hendra viruses have occurred following direct exposure to infected horses. Although Hendra infection is rare in people, 57 percent of individuals with confirmed Hendra infection have died, and some survivors have lasting neurological effects.
Nipah virus is a close relative of the Hendra virus and also causes fatal infections in animals and humans. Like Hendra, Nipah is carried by bats, which can transmit the virus to pigs and humans. Nipah has infected humans who have had close contact with infected pigs or bat secretions and can spread from person to person through close contact. There have been more than a dozen Nipah virus outbreaks to date, with most occurring in Bangladesh. Human case fatality rates have been between 40 and 100 percent. Due to the high mortality rate of Hendra and Nipah infection, and the sporadic and unpredictable nature of outbreaks, effective therapeutics and vaccines are needed.
NIAID-funded researchers at the Uniformed Services University of the Health Sciences (USU) and their collaborators at the National Cancer Institute discovered a potential antibody treatment for Nipah and Hendra virus. The researchers developed a human monoclonal antibody (mAb) known as m102.4 that targets the G glycoprotein of both viruses and found that the mAb effectively protected ferrets after exposure to Nipah or Hendra virus. The mAb was also effective in protecting nonhuman primates after exposure. This nonhuman primate model for Nipah and Hendra was developed with NIAID support by the United States Army Medical Research Institute for Infectious Diseases (USAMRIID), the NIAID Rocky Mountain Laboratories, and the University of Texas Medical Branch. NIAID preclinical services have been used to evaluate m102.4 in tissue culture, create a method to produce the mAb, and improve mAb formulation and stability.
After exposure to Hendra through infected horses, several people in Australia received the therapeutic (under emergency-use authorization) with no adverse effects. The Australian government is currently manufacturing and stockpiling the mAb to use during future outbreaks and is in the process of evaluating it in a Phase I clinical trial.
NIAID has also supported the development of a Hendra vaccine for horses. Vaccinating horses against Hendra will help to prevent them from becoming infected with the deadly virus and is expected to prevent horse-to-human virus transmission. In November 2012, Equivac HeV became the world's first commercially available Hendra vaccine for horses and has been shown to protect cats, ferrets, and monkeys against Nipah virus.
NIAID-funded researchers at USU created the vaccine using one of the Hendra virus proteins (sG) that is essential for infection. The vaccine was evaluated using the same nonhuman primate model supported by NIAID and used to test the mAb. After further testing in small animal models, USU researchers partnered with Pfizer Animal Health and Australia's Commonwealth Scientific and Industrial Research Organisation to produce the vaccine for horses.
Future studies involve adapting this vaccine for use in humans. NIAID-funded researchers have demonstrated that the vaccine protects monkeys from Nipah and Hendra virus infection, an important first step for future use in humans.
Bats, such as the flying fox, have been identified as reservoirs of several infectious diseases.
Credit: J. Epstein copyright EcoHealth Alliance 2013
Novel Therapeutic for Hepatitis B and C: SB 9200
Worldwide, an estimated 240 million people have chronic hepatitis B virus (HBV) infections and another 130-150 million have chronic hepatitis C virus (HCV) infections. These viruses cause irritation and inflammation of the liver, and those who develop chronic infections are at risk for other serious issues such as cirrhosis and liver cancer. While efficacious newly licensed drugs for treatment of chronic HCV infection are available, chronic HBV remains incurable. NIAID has long supported the development of SB 9200, a novel drug produced by Spring Bank Pharmaceuticals. SB 9200 is active against both HCV and HBV. It has shown both direct antiviral activity and host innate immune stimulating activity. Its mechanism of action includes activation of RIG-I, a human protein involved in the activation of the host interferon response.
Spring Bank Pharmaceuticals utilized several different resources in DMID's Preclinical Services Program to test this novel therapeutic. The parent drug, SB 40, first went through in vitro screening and was found to be effective against both HBV and HCV. Next, SB 40 was tested in the NIAID-supported HBV transgenic mouse model to determine dose range, bioavailability and pharmacokinetics, tissue distribution, and toxicity. Results from these studies helped refine the drug, now called SB 9200, so that it could be moved forward in development. In 2011, the company received a grant from NIAID to support the advancement of this therapeutic.
In 2014 Spring Bank Pharmaceuticals completed a Phase 1 clinical trial of SB 9200 in both healthy subjects and HCV-infected patients. They found SB 9200 was well tolerated and antiviral activity was seen at all dose levels except for the lowest dose cohort. Spring Bank Pharmaceuticals is continuing to advance SB 9200 in its HBV clinical program.
A digitally colorized transmission electron micrograph revealing the presence of hepatitis B virions.
Credit: CDC/Dr. Erskine Palmer
Chagas Disease Therapeutic Candidate: K777
Chagas disease, also known as American trypanosomiasis, is caused by the parasite Trypanosoma cruzi, which is transmitted to animals and people through the fecal matter of insect vectors known as triatomine bugs, or "kissing bugs." Left untreated, Chagas disease can cause serious heart and digestive problems. Treatment focuses on killing the parasite in acute infection and managing signs and symptoms in later stages.
Approximately 8 to 10 million people are infected with Chagas disease throughout Latin America, with approximately 50,000 deaths per year. Chagas disease was once entirely confined to the region of the Americas-principally Latin America-but it has now spread to other continents (World Health Organization).
There are only two available therapies for treating Chagas disease: benznidazole and nifurtimox. Significant toxicities are associated with each of these drugs. Safer, more effective therapies for treatment of Chagas are urgently needed.
NIAID-supported basic research has identified K777 as a potential drug candidate for treating Chagas disease. K777 is a potent inhibitor of cruzain, a cysteine protease essential for the parasite.
Support of this project through NIAID grants and preclinical services included drug synthesis, as well as studies of toxicity, dosing, and metabolism. For advanced development, support included substance manufacturing, formulation, pharmacokinetic studies, and repeat toxicity, dosing, and safety studies.
NIAID will continue to support studies of K777 to determine its safety and efficacy for treating Chagas disease. Together with ongoing clinical trials of antifungal drugs for Chagas treatment and the recent approval of an in vitro enzyme strip assay (ESA) as a supplemental test to detect antibodies to T. cruzi, diagnosis and treatment of Chagas disease could change dramatically in the next few years.
A micrograph of T. cruzi, the parasite that causes Chagas disease, in a blood smear.
Credit: CDC/Dr. Mae Melvin
A Rapid Influenza Molecular Diagnostic Platform: Lab-in-a-Tube
Effective treatment of highly contagious diseases such as influenza requires an accurate and speedy diagnosis. Several antiviral drugs for influenza are most effective when taken within 2 days of getting sick, and with the potential of a pandemic, healthcare providers must be able to rapidly and accurately diagnose influenza.
Currently, most influenza strains go undiagnosed or are identified in a laboratory miles from a doctor's office. If the strain is diagnosed, days, if not weeks, may have passed since the patient's throat was swabbed. Recognizing the need for an improved influenza diagnostic, NIAID supported the development of IQuum's Lab-in-a-Tube (Liat) platform -a highly sensitive nucleic acid-based tool that can detect and differentiate influenza A and B strains in about 20 minutes and can now be used in a broad range of healthcare settings. The Liat Influenza A/B Assay is one of the first rapid molecular flu assays to have the sensitivity and specificity of the slower and more complex molecular test methods used in hospital and reference labs.
NIAID has supported early-, mid-, and late-stage development of the Liat platform since 2003. For example, the NIAID-funded Genomic Center for Infectious Diseases at the J. Craig Venter Institute (JCVI) played a critical role in the early development of this diagnostic tool. Influenza genome sequences generated by the JCVI Genomic Center were made publicly available through the National Center for Biotechnology Information and the NIAID Influenza Research Database. These sequences facilitated the design of nucleic acid-based diagnostics. Following basic research success, a collection of NIAID small business and partnership awards supported the Liat platform from the prototype through the current version of the portable and rapid real-time polymerase chain reaction (PCR) assay.
In response to the emergence of the 2009 H1N1 influenza strain, NIAID awarded a grant that enabled the company to immediately incorporate the newly identified 2009 H1N1 strain into their diagnostic tool. The result, the Liat Influenza A/2009 H1N1 Assay, rapidly detected the 2009 H1N1 virus. The Liat assays and accompanying fully automated analyzer received Food and Drug Administration (FDA) clearance in 2011. In 2014, Roche acquired Iquum and the diagnostic platform is now available as Roche's Cobas Lab-in-a-Tube (Liat) system.
The Influenza A/B Assay became part of the Roche Cobas Liat system and received an FDA Clinical Laboratory Improvement Amendments (CLIA) Waiver in September 2015. The CLIA Waiver allows for the broad use of the test by healthcare providers in non-traditional settings, including doctors' offices, emergency rooms, health department and pharmacy clinics, and other healthcare settings.
NIAID provided additional funding to IQuum to expand its diagnostic research to dengue, HIV viral load, and other infectious diseases.
IQuum's lab-in-a-tube is a highly sensitive sample-to-result tool that can detect and differentiate influenza A and B strains near-patient in approximately 20 minutes.
A Diagnostic System To Assess Viral, Bacterial, Fungal, and Parasitic Infections: FilmArray
Accurately diagnosing infections that present with similar symptoms is a high priority for clinicians and public health officials. Rapid and accurate diagnosis enables earlier, targeted treatment and prevents spread of disease. More targeted and effective treatments may also limit the emergence of antimicrobial resistance.
Since 2005, NIAID has awarded small business grants and NIAID partnerships to BioFire Diagnostics, LLC, an affiliate of Biomérieux, to support development of a rapid multiplex diagnostic platform known as the FilmArray. The FilmArray system uses a multi-stage polymerase chain reaction (PCR) to simultaneously detect multiple pathogens, including viruses, bacteria, yeast, and parasites in about one hour. It is a versatile platform that is being used for respiratory pathogens, bloodstream infections, gastrointestinal illness, and central nervous system infections.
NIAID support was essential for development of the FilmArray Respiratory Panel, which can simultaneously detect 20 viral and bacterial respiratory pathogens from patient samples obtained from nasopharyngeal swabs. It is designed for use in both large hospital laboratories and point-of-care settings and can differentiate particular influenza strains such as H1N1. To design the assays in this platform, BioFire used influenza sequences generated by the NIAID Genomic Sequencing Centers, which were made available through the NIAID-supported Influenza Research Database. Viral strains obtained from the NIAID-supported BEI Resources Repository were used to validate the assays. In 2011, the Food and Drug Administration (FDA) cleared the initial FilmArray Respiratory Panel to detect 15 viruses. Assays to detect five additional pathogens were cleared in 2012.
NIAID also provided partial support for the development of three additional FDA-cleared panels:
The FilmArray Blood Culture Identification (BCID) Panel simultaneously tests for 24 Gram-positive bacteria, Gram-negative bacteria, and yeast microbes that cause bloodstream infections (sepsis). It also detects three antimicrobial resistance genes associated with methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE), and carbapenem-resistant Enterobacteriaceae. The FDA cleared this panel in 2013.
The FilmArray Gastrointestinal (GI) Panel tests stool samples for 22 gastrointestinal pathogens including viruses, bacteria and parasites that cause infectious diarrhea. NIAID provided grant support for research, development, and clinical studies of the panel, which received FDA clearance in 2014.
The FilmArray Meningitis/Encephalitis (ME) Panel can simultaneously detect 14 pathogens (bacteria, viruses, and yeast) from cerebrospinal fluid of patients suspected of having meningitis and/or encephalitis. NIAID supported the early development of this panel, including assessment in hospital settings. Within only three years, BioFire successfully initiated development of the panel, completed clinical testing, and received FDA clearance in October 2015.
In addition, NIAID provided partial support to develop an Ebola diagnostic for the FilmArray instrument, which was granted Emergency Use Authorization from the FDA in October 2014. New uses for the FilmArray system are currently under development. These may include panels for biothreats, lower respiratory infections, and sexually transmitted infections.?
The HT-FilmArray system can simultaneously detect 15 respiratory viruses from patient samples in one hour.
Credit: Idaho Technology