By Alice Melao
Inhaled nitric oxide (NO) was shown to be an effective antibacterial agent against Mycobacterium abscessus infection in preclinical studies, as well as in a pilot clinical trial, according to AIT Therapeutics.
NO is a small molecule that is an important mediator of immune defense mechanisms against infections. The compound has been shown to have broad-spectrum antibacterial activity against several strains of bacteria that often infect patients with underlying lung diseases, including cystic fibrosis (CF).
The methods available to treat bacterial infections are many. But among those with any real and lasting effectiveness, their usage is limited. Antibiotics were once the Holy Grail of medicine to deal with devastating diseases that wiped out entire populations. With them, these suffering conditions were almost entirely wiped out and the populace began to learn how to live without the fear of most children dying at a young age. But, as is well known, the age of antibiotic cure-alls is ending and the time of antibiotic resistance is beginning to reach its peak. So, medical researchers are hard at work on all the other opportunities for dealing with bacteria that don’t require these specific groups of compounds.
The Medicine of Viruses
Phage therapy is one such alternative that has begun to see more extensive use over the past two decades.Bacteriophages are lifeforms that have crafted over evolutionary time a niche focused on using bacteria as their reproductive hosts, killing said host in the process. And since they are living beings as well, they actively engage in the selective pressures of finding ways around resistance against them, rather than being a static attack on bacteria like antibiotics are. This means that even the most feared multi-drug resistant bacterial strains have little to no protection against phages.
The primary downside to this treatment is that phages are highly specialized, having formed themselves to only target a particular host species. Therefore, to deal with certain bacteria, one also has to find and be able to cultivate a certain type of phage. Once that step is accomplished, however, it has been found that they can be altered fairly easily to give them variable methods of attack, so as to minimize any potential side effects on the human body while they are killing the bacteria. They can even be set up to synergistically interact with the human immune system to work together to wipe out the bacterial invasion.
With the right phage strain, the largest remaining issue is how to get them into the human body and to the right type of location and system that the bacteria are also attacking from. A large proportion of phage research has gone into finding new ways to do this very thing, as it is one of the inefficient areas of the therapy and, if improved, can drastically heighten the success rates of the treatment and the types of bacterial diseases that can be combated.
It is difficult and time consuming to produce modified phage, with many of them dying in this fabrication. For bacterial diseases of the lungs, such as the kinds that like to colonize those suffering from cystic fibrosis, there is currently no true delivery method of getting phage into the deep lung tissues. And, of course, getting any single treatment approved requires showing success in some sort of animal model, even though the phages may not translate well or at all to anything other than humans. This is one of the major problems this author has with the current approval setup by governments for medical trials.
Microparticles For A Micro World
Scientists at the Georgia Institute of Technology have been seeking a new method for just such a delivery system. Dry powder formulations has seen some positive benefits for effectiveness in recent years, but there lingers the issue of how to use such a powder to delivery living phages to the right spot. To do so would require a very carefully made powder indeed.
The engineering techniques they brought into play were used to make phage-loaded microparticles (phage-MPs), hollow molecular structures formed using water-oil-water emulsion to keep them stable. The bacteria being combated was the opportunistic pathogen Pseudomonas aeruginosa and several strains of phage against it were chosen for the experiment.
The microparticles were housed in a phage-containing solution, allowing them to be filled with the phage after incubation. Though they were filled in a different way than the usual method of them being inside the MPs. Instead, they cover the exterior in this method after the MPs are made, meaning no phage are lost due to solvent usage during MP fabrication from the prior ways other studies used. Three to five phages were contained on the MPs in order to reduce the likelihood of any possible bacterial resistance.
This delivery mechanism also reduces endotoxin production by the phage, thereby minimizing side impacts of their use, with the reduction bringing them down to 0.078 endotoxin units (EUs), far below the accepted FDA limit of 20 EU in treatments. The technique was first tested on petri dishes containing the bacteria to which the phage-MPs were applied. The P. aeruginosa were modified to express green fluorescent protein (GFP) to identify their living location on the plates.
A Complete Victory
After 16 hours of co-incubation, large patches of non-fluorescence showed where the phage had successfully killed off the bacteria, while the control group MPs without a phage coating had no deaths. These zones were also far larger than the applied MP area, showing that the phage were able to spread and extend to other bacteria in the dishes. The same test was done using synthetic sputum to mimic the environment of an animal lung and the bacteria and phages were applied at the same time. There was no visible growth of bacteria after application, showing that the phages were able to both control and wipe them out. A further test showed the phage are also able to get past the protective biofilms of the bacteria that they make under environmental emergencies.
The dry powder formulations were also seen to have a large burst of phages initially, with slow release for two weeks after, the perfect way to allow consistent application and treatment against the bacteria. The final experiment involved using mice infected with the bacteria. A control test using just phage-MPs showed no negative effects on the mice or their lungs after application. Fluorescent phage-MPs also showed that they were only localized to the lungs and nowhere else in the body, as desired. The control using free form phages without microparticles revealed how the dry powder still didn’t allow them to be properly applied, with no major phage levels detected in those mouse lungs, proving that the MPs as a transport vector were required.
When tested on mice infected with P. aeruginosa, the bacterial count dropped by an entire order of magnitude and 100% of the mice survived their pneumonia, while the untreated control group only had 13% survive. For mice with a cystic fibrosis genetic mutation, the same test saw their bacterial counts drop by three orders of magnitude, approaching the limit of what could be detected. The phage-MPs also saw the same effectiveness against multiple strains of the bacteria, meaning that even genetic variance in a population wasn’t enough to defend against them.
A last point of importance is that when testing against a mouse group exposed to phage-MPs long before being infected and later treated, there was no reduction in effect and no antibodies against the phages seemed to develop. So there is likely no performance loss to the treatment if used multiple times.
The New Antibiotics
As a conclusion, the researchers were able to engineer specialized biomaterials made of microparticles that, when coated with bacteriophages, were highly effective at reducing bacterial counts for lung-related diseases, including those resulting from the lowered immune system responses of cystic fibrosis. These phage-MPs are stable and can be stored for a fair amount of time with no loss in phage amounts and can be administered through simple inhalation, meaning younger patients can be treated with less complications.
For lung-related diseases, and likely for broader conditions at large in the medical community, this breakthrough might serve as a major way to allow phage therapy to become more common and used in replacement of or as a sought after alternative to antibiotics. The number of lives this should be able to save in the long run is likely incalculable.
Scott D Sagel MD PhD
Professor of Pediatrics
University of Colorado School of Medicine
MedicalResearch.com: What is the background for this study?
Response: Inflammation is an important feature of cystic fibrosis (CF) lung disease and contributes to lung damage and lung function decline in CF. We need safe and effective anti-inflammatory treatments in CF. Anti-oxidant therapy has been an area of promise, but with mixed results in CF.
This clinical trial, conducted at 15 CF centers affiliated with the cystic fibrosis Foundation Therapeutics Development Network, enrolled 73 patients who were 10 years and older (average age 22 years), with pancreatic insufficiency, which causes malabsorption of antioxidants. Subjects were randomized to either a multivitamin containing multiple antioxidants including carotenoids such as beta(β)-carotene, tocopherols (vitamin E), coenzyme Q10 (CoQ10), and selenium or to a control multivitamin without antioxidant enrichment. The antioxidants used in the study were delivered in a capsule specifically designed for individuals with difficulties absorbing fats and proteins, including those with cystic fibrosis.
MedicalResearch.com: What are the main findings?
Response: Antioxidant supplementation was safe and well-tolerated. Supplemental antioxidants increased antioxidant concentrations in the bloodstream in treated subjects and temporarily reduced inflammation in the blood at four weeks but not 16 weeks. Airway inflammation, as measured in sputum, did not change significantly with antioxidant treatment. Importantly, antioxidant treatment appeared to both prolong the time to the first respiratory illness requiring antibiotics and reduce the frequency of respiratory illnesses they experienced.
MedicalResearch.com: What should readers take away from your report?
Response: Taking a specially formulated antioxidant-enriched multivitamin, containing multiple dietary antioxidants, may decrease respiratory illnesses in people with cystic fibrosis. While more research needs to be done to find a treatment that delivers a sustained anti-inflammatory effect, we believe the prolonged time patients had before their first respiratory illness is clinically meaningful. Also, the cost of a dietary antioxidant-enriched multivitamin is relatively modest compared to other currently available therapies that have been proven to reduce pulmonary exacerbations in cystic fibrosis.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: We still don’t know the optimal dosing of these various dietary antioxidants. We also don’t know the added benefit of antioxidant supplementation in the era of CFTR modulator therapy, emerging treatments that get at the basic protein defect in cystic fibrosis.
MedicalResearch.com: Is there anything else you would like to add?
Response: This clinical trial, funded by a grant from the Cystic Fibrosis Foundation, was an investigator-initiated study led by Scott D. Sagel, MD, PhD, a Professor of Pediatrics at Children’s Hospital Colorado and Director of the University of Colorado Cystic Fibrosis Center. It was not an industry initiated or funded trial. Callion Pharma manufactured the antioxidant-enriched and control multivitamins and provided them at no charge for this study.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Effects of an Antioxidant-enriched Multivitamin in Cystic Fibrosis: Randomized, Controlled, Multicenter Trial
Scott D Sagel , Umer Khan , Raksha Jain , Gavin Graff , Cori L Daines , Jordan M Dunitz , Drucy Borowitz , David M Orenstein , Ibrahim Abdulhamid , Julie Noe , John P Clancy , et al
https://doi.org/10.1164/rccm.201801-0105OC PubMed: 29688760
American Journal of Respiratory and Critical Care Medicine
Published Online: April 24, 2018
Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.
Original interview article here.
By Vijaya Iyer
Cystic fibrosis (CF) patients have a higher amount of harmful gut bacteria and increased levels of intestinal inflammation than healthy people, according to researchers.
Their study, “Altered intestinal microbiota composition, antibiotic therapy and intestinal inflammation in children and adolescents with cystic fibrosis,” was published in the journal PLOS One.
CF predominantly affects the lungs, but it can also cause gastrointestinal complications. The CFTR protein defect (the cause of CF) is abundant in the gastrointestinal tract of patients and affects the normal structure of the intestine. This defect could influence the diversity of the bacteria present in the gut (also called the gut microbiome). Continue reading Harmful Bacteria Replace Beneficial Ones in Gut of CF Patients
By Claudia Dall’Osso, Ph.D., Ian Love, Ph.D., and Nuno Antunes, Ph.D., Decision Resources Group (DRG)
Commercial success in the pharmaceutical industry requires that clinical programs, in addition to demonstrating clinical effectiveness, also provide data supporting a drug’s value. The Institute for Clinical and Economic Research (ICER), a U.S.-based cost-effectiveness watchdog, recently released an analysis suggesting that Vertex Pharmaceuticals’ cystic fibrosis (CF) franchise — Kalydeco, Orkambi, and the recently launched Symdeko — while offering meaningful clinical efficacy, would require discounts of approximately 70 percent1 to be cost-effective.
Here, we review ICER’s cost-effectiveness analysis of the Vertex CF franchise to highlight lessons for orphan drug developers related to clinical trial designs and outcome metrics that would facilitate more favorable cost-effectiveness evaluations by stakeholders who employ cost-utility modeling (e.g., ICER, U.K.’s National Institute for Health and Care Excellence [NICE]).
Calculating The Cost-Effectiveness Of Vertex’s Cystic Fibrosis Franchise
In a cost-utility model, health economic analysts strive to calculate the incremental cost to gain an extra quality-adjusted life year (QALY); they estimate a therapy’s impact on the level of utility patients are deriving from their life based on their health status and incorporate these data into a quantitative estimate of QALYs (Figure 1). The goal of the cost-utility analysis is to determine whether a therapeutic intervention changes the QALYs that patients will accumulate over a set time period (e.g., lifetime), and at what added cost. The threshold for what is considered an acceptable incremental cost per QALY varies by stakeholder; ICER typically presents a sensitivity analysis across a range of thresholds (e.g., $50,000 to $500,000 per QALY for an ultra-rare disease like CF).
In our view, data gaps opened the possibility of a potential undervaluation of the Vertex CF transmembrane conductance (CFTR) modulators on several metrics and, ultimately, on overall survival in the context of the ICER model. Vertex’s pivotal clinical trials captured the effect of CFTR modulators on the two organs chiefly affected in CF — the lungs and the pancreas — with outcome metrics for pulmonary function, percent-predicted 1-second forced expiratory volume (ppFEV1), and pulmonary exacerbation rate, as well as pancreatic sufficiency (body weight) (Figure 2). However, data on metrics assessing emerging complications (e.g., CF-dependent diabetes or bacterial infections), impact on use of other medications (e.g., pancreatic enzyme replacement therapy, mucolytics), reduction in healthcare resource utilization, or reduction in disease burden were far more limited, but these attributes were included in ICER’s cost-effectiveness analysis. Lacking clear clinical trial data on the metrics outlined above, health economists relied on arguably conservative assumptions to estimate the impact of the Vertex CFTR modulators on these domains. Because the Vertex CF franchise has a relatively short market history, and the long-term risks/benefits of the drugs are incompletely understood, assumptions to model the long-term impact of these medicines were also necessary.
For instance, to evaluate survival, ICER modeled the impact of CF-related diabetes in its analysis of CF patients’ health status. Owing to the dearth of clinical trial data on CF-related diabetes in the development program for the Vertex drugs, the company’s CFTR modulators were assumed not to impact this outcome (Figure 2). Treatment with the Vertex CFTR modulators was also conservatively assumed to have no long-term impact on weight after an initial increase and, without long-term data, the drugs’ impact on ppFEV1 beyond two years of treatment was modeled as a 50 percent reduction in the rate of ppFEV1 decline.
Notably, several CF experts interviewed by DRG consider it possible that early treatment of newborns could prevent disease development. The potential impact of early treatment with CFTR modulators on disease development and survival was not explored in the ICER analysis; although little data is available to support such an impact of the Vertex drugs, ICER has considered such scenarios largely unsupported in other evaluations (e.g., a cost-effectiveness evaluation of Spark Therapeutics’ Luxturna for the treatment of retinitis pigmentosa).
The translation of clinical trial data to utility is a second area wherein a manufacturer may lose traction in a cost-utility analysis, if the utility calculation isn’t sufficiently comprehensive or if the drug’s data package is insufficient to support its impact on all relevant metrics. In the ICER analysis of the Vertex franchise, health economists used the ppFEV1 metric to derive a utility curve by assigning a level of benefit to a specific ppFEV1 value. Although this is the most straightforward approach, it also results in an assessment of health benefits that relies exclusively on a mechanical respiratory metric, which may not adequately capture the quality of life experienced by patients, especially considering the multi-organ nature of CF. Indeed, at the May 17 presentation of the ICER model, stakeholders from the Cystic Fibrosis Foundation levied this criticism. Furthermore, ICER’s sensitivity analyses showed that changes in the relationship between ppFEV1 and utility could significantly affect the overall cost-effectiveness assessment. Notably, an alternative scenario in which the utility was increased by 5 percent, to account for clinical effects of a drug beyond pulmonary function, led to a 15 percent decrease in the cost-effectiveness ratio.
Similarly, the impact of the Vertex franchise on payer budgets in the ICER model related only to pulmonary supportive care, while other non-pulmonary expenses remained unchanged — an assumption made in the context of available data, but one that may not fully reflect the benefit of the drugs. Furthermore, the CFTR modulators did not impact the burden of supportive care for CF patients in the model, nor did they impact patients’ productivity. Ultimately, suboptimal alignment of clinical trial data with the demands of a comprehensive (e.g., multi-organ) cost-effectiveness model may have diminished the opportunity for the Vertex franchise to perform maximally in this cost-utility analysis.
Key Lessons And Takeaways For Drug Developers
Although clinical outcome data collected by Vertex was sufficient to gain an FDA green light, it was not sufficient to support a comprehensive analysis of cost-effectiveness in this multi-organ disease. As such, assumptions regarding drug impact were necessary in areas not adequately supported by data, opening the possibility for a suboptimal cost-effectiveness evaluation. To support more favorable and data-supported evaluations, developers should design clinical trials with an eye on cost-effectiveness.
- Prior to initiating clinical trials, manufacturers should consider how a health status model is likely to be designed to assess cost-effectiveness. They should consider enrolling the assistance of academic researchers to understand which metrics may be important in such a model and to aid in the development of a reliable model in an area where none is established. With this analysis in mind, developers should strive to design a clinical program that covers relevant metrics and the durability of a drug’s impact on them. Indeed, an alternative scenario developed by ICER showed that a change in the long-term effectiveness assumption on ppFEV1 would have a profound impact on the final cost-effectiveness assessment; for Kalydeco, assuming no decline in ppFEV1 after the first two years (rather than 50 percent) decreased the incremental cost-effectiveness ratio ($ per QALY) by approximately 35 percent.
- Developers should work to understand how key clinical metrics in a given disease area are translated into utility. In a disease with an established function, it is prudent to carefully survey the relevant literature. When developing a pioneering treatment, manufacturers should consider investment into the development of a utility curve that accurately accomplishes this, which would likely facilitate a reliable QALY calculation or at least more detailed/specific alternative scenarios and sensitivity analyses.
- Understand the patient journey and track healthcare resource utilization during a clinical trial to more fully support an accurate assessment of cost of care, as a favorable impact on direct healthcare costs is important to attain widespread reimbursement.
- Although metrics such as burden of care, caregiver burden, or productivity loss are difficult to rigorously track, they can be immensely valuable in highlighting the favorable indirect effects of disease-modifying drugs beyond the clinical efficacy. Understanding patients’ pain points and, ideally, tracking these metrics when possible (e.g., with real-world data or social media listening analyses) may further strengthen and support conventional metrics from clinical trials.
As market access hurdles intensify, and ICER’s analyses increasingly inform payer policy, anticipating and preparing for cost-utility analyses early in the design of a clinical program will be paramount to support a medicine’s value proposition with U.S. insurers.
Original article found here.
By: Alice Melao
A natural component found in cinnamon oil, known as cinnamaldehyde or CAD, may be able to prevent Pseudomonas aeruginosa bacteria from spreading in an organism and inhibit their ability to form antibiotic-resistant biofilms, researchers show.
These findings may support further study into anti-microbial medications that can help control the behavior of these so-called superbugs, or treatment-resistant bacteria, which represent a serious healthcare problem for people with cystic fibrosis and other diseases.
The discovery was reported in “Cinnamaldehyde disrupts biofilm formation and swarming motility of Pseudomonas aeruginosa,” published in the journal Microbiology.
“Humans have a long history of using natural products to treat infections, and there is a renewed focus on such antimicrobial compounds,” Sanjida Halim Topa, PhD, a researcher at Swinburne University of Technology in Australia, and lead study author, said in a university news release. “Natural products may offer a promising solution to this problem.”
Cinnamaldehyde, one of the major components of cinnamon oil, is responsible for its characteristic flavor. This compound is known to have antimicrobial activity against many bacteria, including P. aeruginosa; a stomach ulcer-causing bacteria called Helicobacter pylori; and Listeria monocytogenes, which is responsible for the food-borne infection listeriosis.
“We hypothesized that using natural antimicrobials, such as essential oils, might interfere in [drug-resistant] biofilm formation,” Topa said. “Though many previous studies have reported antimicrobial activity of cinnamon essential oil, it is not widely used in the pharmaceutical industry.”
Working with researchers at Nanyang Technological University in Singapore, the team conducted several experiments to evaluate the impact of different concentrations of cinnamaldehyde on P. aeruginosa biofilms.
They found that non-lethal amounts of the essential oil compound could disrupt by 75.6 % antibiotic-resistant, preformed P. aeruginosa biofilms. Cinnamaldehyde was found to prevent the production of a bacterial-signaling protein essential for bacteria communication and biofilm formation. [Biofilms, or microbe communities whose growth is facilitated by the thick and sticky mucus that marks CF, are known to promote antibiotic resistance in P. aeruginosa lung infections.]
In a concentration-dependent manner, cinnamaldehyde also could reduce the motility of the bacteria, preventing them from spreading elsewhere, the scientists reported.
These findings, the researchers wrote, show “CAD can disrupt biofilms and other surface colonization phenotypes through the modulation of intracellular signaling processes.”
They are now investigating the use of cinnamaldehyde embedded-wound dressings as a way to treat skin infections.
Original article here.
Another virtual event for our adult CF community!
About CF MiniCon: Transplant
This virtual event will explore all stages of the transplant process and allow those who are considering a transplant, preparing for transplant, or post-transplant to connect with others, learn more about the process, and share their experiences.
The CF MiniCon will feature a keynote presentation followed by storytelling panel discussions and small group video breakouts.
This event is open to adults with CF, their family members, and caregivers age 18 or older.
WEDNESDAY, AUGUST 15
6:30 – 10 p.m. ET | 5:30 – 9 p.m. CT | 4:30 – 8 p.m. MT | 3:30 – 7 p.m. PT
By Ashraf Malhas, PhD.
An earlier diagnosis and treatment of nontuberculous mycobacteria (NTM) infection in patients with cystic fibrosis (CF) may positively affect the patient’s lung function, a study suggests.
NTM are a group of bacterial species, found in soil and water, which are not usually associated with human disease, except if they infect susceptible individuals, such as CF patients.
An increasing incidence of NTM infections in CF patients has been observed, with recent studies reporting a prevalence of 32.7%. The exact reasons behind this, the risk factors, the species involved, and effective treatments for NTM infections in CF patients remain largely unknown.
In the study “Clinical course and significance of nontuberculous mycobacteria and its subtypes in cystic fibrosis,” published in the journal BMC Infectious Diseases, researchers analyzed the prevalence of NTM infections in CF patients to identify factors associated with these infections, as well as monitor current treatments.
The study initially involved 360 CF patients, of whom 30 (8%) were identified as being positive for NTM infection. Of these, 28 patients were further analyzed, and their results compared with 26 matched CF patients not infected with NTM (the control group).
Within the NTM group, 17 patients were infected with a class of NTM known as slow-growing, eight patients were infected with rapidly growing NTM, while three were positive for both types.
Those infected with slow-growing NTM were generally older (range of 6.4 to 41.6 years) than those infected with the rapid-growing types (3.1 to 21.5 years), but that difference did not reach statistical significance. However, the age at CF diagnosis was significantly lower in the slow-growing NTM group compared to the rapid-growing NTM group.
When lung function was assessed in the two groups, researchers found that lung function as measured by predicted expiratory flow was significantly higher before NTM infection, regardless of the type of NTM.
Regarding treatment patterns, the team found that significantly more patients infected with slow-growing NTM had received penicillin/beta-lactamase and rifampin following infection compared to before infection.
“An earlier CF diagnosis was associated with a higher isolation of slow-growing NTM and greater antimicrobial use after infection,” the researchers wrote, adding that “NTM acquisition is associated with a worsening of [lung function]. Thus, both the early diagnosis and treatment of an NTM infection in patients with CF may positively impact lung function.”
The team believes that “increased awareness by clinicians on different NTM subtypes and more universal treatment plan for NTM infection in the CF population may positively impact patient management and outcomes.”
Original article here.
By Chris Waters
Maybe you’ve had the experience of wading in a stream and struggling to keep your balance on the slick rocks, or forgetting to brush your teeth in the morning and feeling a slimy coating in your mouth. These are examples of bacterial biofilms that are found anywhere a surface is exposed to bacteria in a moist environment.
Besides leading to falls in streams or creating unhealthy teeth, biofilms can cause large problems when they infect people. Biofilms, multicellular communities of bacteria that can grow on a surface encased in their own self-produced matrix of slime, can block immune cells from engulfing and killing the bacteria or prevent antibodies from binding to their surface.
On top of this, bacteria in a biofilm resist being killed by antibiotics due to the sticky nature of the matrix and activation of inherent resistant mechanisms, such as slow-growing cells or the ability to pump antibiotics out of the cell.
Biofilms are one of the primary growth modes of bacteria, but all antibiotics currently used clinically were developed against free-swimming planktonic bacteria. This is why they do not work well against biofilms.
My laboratory studies how and why bacteria make biofilms, and we develop new therapeutics to target them. Because antibiotic resistance is the most problematic aspect of biofilms during infections, we set out to identify novel molecules that could enhance antibiotic activity against these communities.
We discovered that an antimicrobial that has recently obtained a bad reputation for overuse in many household products could be the secret sauce to kill biofilms.
The hunt for antibiotic superchargers
To find such compounds, we developed an assay to grow plates of 384 tiny biofilms of the bacterium Pseudomonas aeruginosa. We did this to screen for molecules that enhance killing by the antibiotic tobramycin. We chose this bacterium and this antibiotic as our test subjects because they are commonly associated with cystic fibrosis lung infections and treatment.
People with cystic fibrosis (CF) are at particular risk from biofilm-based infections. These infections often become chronic in the lungs of cystic fibrosis patients and are often never cleared, even with aggressive antibiotic therapy.
After we screened 6,080 small molecules in the presence of tobramycin, we found multiple compounds that showed the antibiotic enhancement activity we were searching for. Of particular interest was the antimicrobial triclosan
Another fact that piqued our interest is that P. aeruginosa is resistant to triclosan. Indeed, treatment with either tobramycin or triclosan alone had very little activity against P. aeruginosa biofilms, but we found that the combination was 100 times more active, killing over 99 percent of the bacteria.
We further studied this combination and found that it worked against P. aeruginosa and other bacterial species that had been isolated from the lungs of CF patients. The combination also significantly enhanced the speed of killing so that at two hours of treatment, virtually all of the biofilm is eradicated.
Our efforts are now focused on pre-clinical development of the tobramycin-triclosan combination. For CF, we envision patients will inhale these antimicrobials as a combination therapy, but it could also be used for other applications such as diabetic non-healing wounds.
Although questions about the safety of triclosan have emerged in the mainstream media, there are actually dozens of studies, including in humans, concluding that it is well tolerated, summarized in this extensive EU report from 2009. My laboratory completely agrees that triclosan has been significantly overused, and it should be reserved to combat life-threatening infections.
The next steps for development are to initiate safety, efficacy and pharmacological studies. And thus far, our own studies indicate that triclosan is well tolerated when directly administered to the lungs. We hope that in the near future we will have enough data to initiate clinical trials with the FDA to test the activity of this combination in people afflicted with biofilm-based infections.
We think our approach of enhancing biofilm activity with the addition of novel compounds will increase the usefulness of currently used antibiotics. Learning about how these compounds work will also shed light on how bacterial biofilms resist antibiotic therapy.
Original article here.