New treatment kills off infection that can be deadly to cystic fibrosis patients

A new treatment developed by researchers at Aston University and Birmingham Children's Hospital has been found to completely kill a bacterial infection that can be deadly to cystic fibrosis patients and other chronic lung conditions such as bronchiectasis.

The findings, which are published in the journal Scientific Reports, show that scientists from Aston University, Mycobacterial Research Group, combined doses of three antibiotics—amoxicillin and imipenem-relebactam and found it was 100% effective in killing off the infection which is usually extremely difficult to treat in patients with cystic fibrosis. The infection results in severe decline in lung function and sometimes death.

                                

amoxicillin                                                                   Imipenem  \

 Relebactam

Cystic fibrosis (CF) is a genetic condition affecting more than 10,000 people in the UK (Cystic Fibrosis Trust) and there are more than 70,000 people with the condition worldwide (Cystic Fibrosis Foundation). While bronchiectasis affects 210,000 people in the UK (British Lung Foundation).

Mycobacterium abscessus is a bacterial pathogen from the same family that causes tuberculosis, which causes serious lung infections in people (particularly children) with lung disorders, most notably cystic fibrosis. It is highly drug resistant. Currently patients are given a cocktail of antibiotics that cause serious side effects including severe hearing loss and often doesn't result in cure.

The researchers used samples of the pathogen taken from 16 infected cystic fibrosis patients and tested the new drug combination to discover how much was required to kill the bacteria. They found the amounts of amoxicillin-imipenem-relebactam required were low enough to be given safely to patients.

Until now Mycobacterium abscessus has been virtually impossible to eradicate in people with cystic fibrosis. It can also be deadly if the patient requires a lung transplant because they are not eligible for surgery if the infection is present.

In the UK, of the 10,000 people living with cystic fibrosis, Mycobacterium abscessus infects 13% of all patients with the condition. This new treatment is advantageous not only because it kills off the infection, but it does not have any side-effects on patients, thus ensuring their quality of life and greatly improving survival chances for infected CF patients.

Dr. Jonathan Cox, Lecturer in Microbiology, Aston University and leader of the team that discovered this new treatment said: "This new drug combination is a significant step forward for patients with cystic fibrosis that get infected with the deadly Mycobacterium abscessus bacteria. Our new drug combination is significantly less toxic than those currently used, and so far we have managed to kill every patient's bacterial isolate that we have received.

"This shows our drugs, when used in combination, are widely effective and could therefore make a huge difference to people whose treatment options are currently limited.

"Because amoxicillin is already widely available and imipenem-relebactam has just been approved for use by the Food and Drug Administration (FDA) in the US, these drugs are already available to clinicians. We therefore hope to start treating patients as soon as possible. "

The findings of this research will impact children being treated for the infection at Birmingham Children's Hospital—who part funded the research—but it can also be used nationally and further afield.

With more funding, the next stage of the research will be to test the treatment on more people with CF infected by this bacterium, comparing it to the antibiotics that are currently used.

Dr. Maya Desai, Consultant in Respiratory Paediatrics, Birmingham Children's Hospital added: "This exciting development will significantly impact on the care of CF patients globally. It has been possible only with close collaboration between Aston University and Birmingham Children's Hospital both from a clinical research and financial point of view."

Dr. Paula Sommer, Head of Research at the Cystic Fibrosis Trust said: "It's exciting that these lab-based studies investigating new antibiotic treatments for M. abscessus infection are showing such promise and adding to our expanding knowledge of this devastating bug.

"Mycobacterium abscessus also known as NTM, is the most feared infection a person with cystic fibrosis can develop. Taking drugs to treat NTM can add to an already significant regime of daily treatments and take up to a year to clear infections. We look forward to a time when effective, short courses of treatment are available to treat NTM."

https://en.wikipedia.org/wiki/Amoxicillin

https://en.wikipedia.org/wiki/Imipenem                                                                                                      https://en.wikipedia.org/wiki/Relebactam

https://medicalxpress.com/news/2019-10-fda-drug-common-cystic-fibrosis.html

FDA Approves Pretomanid for Highly Drug-Resistant Forms of Tuberculosis

In continuation of my update on Pretomanid

 Pretomanid, a novel compound developed by the non-profit organization TB Alliance, was approved by the U.S. Food & Drug Administration (FDA) today for treating some of the most drug-resistant forms of tuberculosis (TB).1 The new drug was approved under the Limited Population Pathway for Antibacterial and Antifungal Drugs (LPAD pathway) as part of a three-drug, six-month, all-oral regimen for the treatment of people with extensively drug-resistant TB (XDR-TB) or multidrug-resistant TB (MDR-TB) who are treatment-intolerant or non-responsive (collectively “highly drug-resistant TB”).1,2

The LPAD pathway was established by FDA as a tool to encourage further development of antibacterial and antifungal drugs to treat serious, life-threatening infections that affect a limited population of patients with unmet needs. 

“FDA approval of this treatment represents a victory for the people suffering from these highly drug-resistant forms of the world’s deadliest infectious disease,” said Mel Spigelman, MD, president and CEO of TB Alliance. “The associated novel regimen will hopefully provide a shorter, more easily manageable and highly efficacious treatment for those in need.”

The three-drug regimen consisting of bedaquiline, pretomanid and linezolid – collectively referred to as the BPaL regimen – was studied in the pivotal Nix-TB trial across three sites in South Africa. The trial enrolled 109 people with XDR-TB as well as treatment-intolerant or non-responsive MDR-TB.2

Nix-TB data have demonstrated a successful outcome in 95 of the first 107 patients after six months of treatment with BPaL and six months of post-treatment follow-up.2 For two patients, treatment was extended to nine months. The new drug application contains data on 1,168 people who have received pretomanid in 19 clinical trials that have evaluated the drug’s safety and efficacy.2 Pretomanid has been clinically studied in 14 countries.

TB, in all forms, must be treated with a combination of drugs; the most drug-sensitive forms of TB require six months of treatment using four anti-TB drugs.3 Treatment of XDR-TB or treatment-intolerant/non-responsive MDR-TB has historically been lengthy and complex; most XDR-TB patients currently take a combination of as many as eight antibiotics, some involving daily injections, for 18 months or longer.3,4 Prior to recent introduction of new drugs for drug-resistant TB, the World Health Organization (WHO) has reported estimates for treatment success rates of XDR-TB therapy at approximately 34 percent and about 55 percent for MDR-TB therapy.4

“Until very recently, people infected with highly drug-resistant TB had poor treatment options and a poor prognosis,” said Dr. Francesca Conradie, principal investigator of the Nix-TB trial. “This new regimen provides hope with 9 out of 10 patients achieving culture negative status at 6 months post-treatment  with this short, all-oral regimen."

Pretomanid is a new chemical entity and a member of a class of compounds known as nitroimidazooxazines. TB Alliance acquired the developmental rights to the compound in 2002. It has been developed as an oral tablet formulation for the treatment of TB in combination with bedaquiline and linezolid, two other anti-TB agents, and is now indicated for use in a limited and specific population of patients.1 Adverse reactions reported during the Nix-TB trial of the BPaL regimen include hepatotoxicity, myelosuppression, as well as peripheral and optic neuropathy.1 Please see additional safety information in the Important Safety Information below.

Pretomanid is only the third new anti-TB drug approved for use by FDA in more than 40 years, as well as the first to be developed and registered by a not-for-profit organization.5,6 Pretomanid was granted Priority Review, Qualified Infectious Disease Product, and Orphan Drug status. As a product development partnership, TB Alliance has collaborated with and received significant support from numerous governments, academia, philanthropic institutions, the private sector, civil society organizations and other partners over the course of pretomanid’s development.

Pretomanid is expected to be available in the United States by the end of this year. In addition to the U.S. FDA, TB Alliance has submitted pretomanid as part of the BPaL regimen for review by the European Medicines Agency and has provided data to the World Health Organization for consideration of inclusion in treatment guidelines for highly drug-resistant TB.

https://en.wikipedia.org/wiki/Pretomanid

TB Medicine Pretomanid Enters Regulatory Review Process in the United States

 TB Alliance’s new drug application (NDA) for the novel tuberculosis (TB) drug candidate pretomanid has been accepted for review by the United States Food and Drug Administration (FDA). The application is for the use of pretomanid as part of a new regimen, in combination with bedaquiline and linezolid, for the treatment of extensively drug-resistant (XDR) TB, treatment intolerant multidrug-resistant (MDR) TB, and treatment non-responsive MDR-TB.

The NDA for pretomanid has been granted Priority Review by FDA. The Prescription Drug User Fee Act (PDUFA) action date for an FDA decision is in third quarter 2019.

TB Alliance will work with manufacturing partners to ensure that pretomanid, if approved for use in the BPaL regimen, will be accessible to those who need it.

About Pretomanid and the BPaL Regimen

Pretomanid is a new chemical entity and a member of a class of compounds known as nitroimidazooxazines. It has been studied in 20 clinical trials alone or in combination with other anti-TB drugs. Since TB Alliance began development of pretomanid in 2002, it has been administered in a clinical trial setting to more than 1,200 people in 14 countries.

The BPaL regimen (comprised of bedaquiline, pretomanid and linezolid) was first studied clinically in the Phase 3 Nix-TB trial. Nix-TB participants with XDR-TB and treatment intolerant or nonresponsive MDR-TB were enrolled for treatment with the BPaL regimen for six months, extendable to nine months, with the intent to cure. Nix-TB is an open label, single arm trial. According to a modified intention-to-treat analysis of interim results on the first 75 participants presented at the 2018 Union World Conference on Lung Health, 89% of the trial participants had a favorable outcome with their clinical infection resolved and sputum cultures negative for TB after six months of treatment and six months of post-treatment follow-up.

https://www.tballiance.org/portfolio/compound/pretomanid

https://en.wikipedia.org/wiki/Pretomanid

https://www.drugbank.ca/drugs/DB05154

TB Medicine Pretomanid Enters Regulatory Review Process in the United States

Ancient Chinese medicine for malaria could potentially aid in treatment of tuberculosis

In continuation of my update on Artemisinin

A centuries-old herbal medicine, discovered by Chinese scientists and used to effectively treat malaria, has been found to potentially aid in the treatment of tuberculosis and may slow the evolution of drug resistance.

In a promising study led by Robert Abramovitch, a Michigan State University microbiologist and TB expert, the ancient remedy artemisinin stopped the ability of TB-causing bacteria, known as Mycobacterium tuberculosis, to become dormant. This stage of the disease often makes the use of antibiotics ineffective.

The study is published in the journal Nature Chemical Biology.

"When TB bacteria are dormant, they become highly tolerant to antibiotics," Abramovitch said, an assistant professor in the College of Veterinary Medicine. "Blocking dormancy makes the TB bacteria more sensitive to these drugs and could shorten treatment times."

One-third of the world's population is infected with TB and the disease killed 1.8 million people in 2015, according to the Centers for Disease Control and Prevention.

Mycobacterium tuberculosis, or Mtb, needs oxygen to thrive in the body. The immune system starves this bacterium of oxygen to control the infection. Abramovitch and his team found that artemisinin attacks a molecule called heme, which is found in the Mtb oxygen sensor. By disrupting this sensor and essentially turning it off, the artemisinin stopped the disease's ability to sense how much oxygen it was getting.

"When the Mtb is starved of oxygen, it goes into a dormant state, which protects it from the stress of low-oxygen environments," Abramovitch said. "If Mtb can't sense low oxygen, then it can't become dormant and will die."

Abramovitch indicated that dormant TB can remain inactive for decades in the body. But if the immune system weakens at some point, it can wake back up and spread. Whether it wakes up or stays 'asleep' though, he said TB can take up to six months to treat and is one of the main reasons the disease is so difficult to control.

"Patients often don't stick to the treatment regimen because of the length of time it takes to cure the disease," he said. "Incomplete therapy plays an important role in the evolution and spread of multi-drug resistant TB strains."

He said the research could be key to shortening the course of therapy because it can clear out the dormant, hard-to-kill bacteria. This could lead to improving patient outcomes and slowing the evolution of drug-resistant TB.

After screening 540,000 different compounds, Abramovitch also found five other possible chemical inhibitors that target the Mtb oxygen sensor in various ways and could be effective in treatment as well.

"Two billion people worldwide are infected with Mtb," Abramovitch said. "TB is a global problem that requires new tools to slow its spread and overcome drug resistance. This new method of targeting dormant bacteria is exciting because it shows us a new way to kill it."

Ref : http://www.nature.com/nchembio/journal/vaop/ncurrent/full/nchembio.2259.html

FDA Grants Soligenix “Fast Track” Designation for SGX943 for the Treatment of Melioidosis

Soligenix, Inc. (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announced today that its SGX943 (dusquetide) development program has received “Fast Track” designation from the US Food and Drug Administration (FDA) as adjunctive therapy with other antibacterial drugs, for the treatment of melioidosis, a serious and potentially life-threatening condition.

 SGX943 (dusquetide)

Fast track is a designation that the FDA reserves for a drug intended to treat a serious or life- threatening condition and one that demonstrates the potential to address an unmet medical need for the condition. Fast track designation is designed to facilitate the development and expedite the review of new drugs. For instance, should events warrant, Soligenix will be eligible to submit a new drug application (NDA) for SGX943 on a rolling basis, permitting the FDA to review sections of the NDA prior to receiving the complete submission. Additionally, NDAs for fast track development programs ordinarily will be eligible for priority review, which imparts an abbreviated review time of approximately six months.

“We are very pleased to have been granted fast track designation from the FDA,” stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix. “We believe that the FDA’s action in granting fast track designation validates the unmet medical need that currently exists for the treatment of melioidosis and for the potential key role SGX943 can serve as a therapy in this rare, life-threatening disease. We look forward to working with the federal government to advance this biodefense development program.”

About Melioidosis

Melioidosis is a potentially fatal infection caused by the Gram-negative bacillus, Burkholderia pseudomallei(Bps). Highly resistant to many antibiotics, Bps can cause an acute disease characterized by a fulminant pneumonia and a chronic condition that can recrudesce. There is no preventive vaccine or effective immunotherapy for melioidosis. Therefore, there is a significant medical need for improved prevention and therapy.

Bps and the closely related Burkholderia mallei (Bm) are considered possible biological warfare agents by the Department of Health and Human Services (DHHS) because of the potential for widespread dissemination through aerosol. Bps is classified as a Tier 1 biothreat and a category B priority pathogen by the NIAID and is a top 5 priority in the most recent Public Health Emergency Medical Countermeasure Enterprise (PHEMCE) Strategy document.

Bps infection (melioidosis) is a major public health concern in the endemic regions of Southeast Asia and Northern Australia. Moreover, the organism has a worldwide distribution and the full extent of global spread is likely underestimated. Bps activity is seen in Southeast Asia, South America, Africa, the Middle East, India, and Northern Australia. The highest pockets of disease activity occur in Northern Australia and Northeast Thailand, Burma and Vietnam, and is likely under-reported in China. In Northeast Thailand, the mortality rate associated with Bps infection is over 40%, making it the third most common cause of death from infectious disease in that region after HIV/AIDS and tuberculosis.

About SGX943

SGX943 is the drug product designation for the active ingredient dusquetide in the treatment of melioidosis. Dusquetide is an IDR, a new class of short, synthetic peptides that has a novel mechanism of action in that it has simultaneous anti-inflammatory and anti-infective activity. IDRs have no direct antibiotic activity but modulate host responses, increasing survival after infections with a broad range of bacterial Gram-negative and Gram-positive pathogens, as well as accelerating resolution of tissue damage following exposure to a variety of agents including bacterial pathogens, trauma and chemo- and/or radiation-therapy. Dusquetide has demonstrated safety in a Phase 1 clinical study in 84 healthy human volunteers and preliminary efficacy and safety in an exploratory Phase 2 clinical study in 111 patients with oral mucositis due to chemoradiation therapy for head and neck cancer. Dusquetide has also previously demonstrated efficacy in numerous animal disease models including melioidosis, mucositis, colitis, skin infection and other bacterial infections. Dusquetide and related analogs have a strong intellectual property position, including composition of matter. Dusquetide was developed pursuant to discoveries made by Professors B. Brett Finlay, PhD and Robert Hancock, PhD of the University of British Columbia.

New drug regimens could significantly improve treatment for tuberculosis

Researchers from UCLA and Shanghai Jiao Tong University have made an important step toward a substantially faster and more effective treatment for tuberculosis, which infects some 10 million people and causes 1.5 million deaths each year.

Combination therapy, which utilizes a series of drugs, is a clinical standard for many major diseases. However, the number of potential combinations of different drugs and dose levels can be in the billions, making the prospect of choosing the best one seem daunting.

The research was published in the Proceedings of the National Academy of Sciences.

In the study, researchers used a technique called feedback system control, which was developed at UCLA, to study cells infected with the bacteria that cause tuberculosis. They quickly narrowed combinations of 14 different tuberculosis drugs with five different doses -- resulting in 6 billion possibilities -- into several promising combination treatments that kill the bacteria that cause tuberculosis much faster than the standard regimen used to treat tuberculosis.

"Designing a drug combination with optimized drug-dose ratios has, until now, been virtually impossible," said Chih-Ming Ho, the study's principal investigator and the Ben Rich-Lockheed Martin Chair Professor at UCLA's Henry Samueli School of Engineering and Applied Science. "Feedback system control technology demonstrated it can pinpoint these best possible ratios for a wide spectrum of diseases."

"If our findings are confirmed in human studies, the new drug regimens that we have identified should dramatically shorten the time needed to treat tuberculosis," said Dr. Marcus Horwitz, a senior author on the research and a distinguished professor of medicine and microbiology, immunology and molecular genetics at the UCLA David Geffen School of Medicine. "This will increase the likelihood of successful treatment and decrease the likelihood of patients developing drug-resistant tuberculosis. A highly successful and rapid treatment may hasten the eventual eradication of tuberculosis."

New drug regimens could significantly improve treatment for tuberculosis: Researchers from UCLA and Shanghai Jiao Tong University have made an important step toward a substantially faster and more effective treatment for tuberculosis, which infects some 10 million people and causes 1.5 million deaths each year.

Scientists identify new agent to combat tuberculosis

(Griselimycin)

Above pic: The protein forms a homodimeric ring (shown as blue cartoon & surface representation). Each polypetide chain binds one molecule of griselimycin (red). The optimized compound cyclohexylgriselimycin contains an additional cyclohexane moiety (yellow, shown only for the ligand in the foreground).

According to figures of the World Health Organization, some 8.7 million people contracted tuberculosis in 2012 and this disease is fatal for approximately 1.3 million people throughout the world each year. One of the main problems is that the tuberculosis pathogens have become resistant to the antibiotics used to fight them. Scientists from the Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) in Saarbrücken, the Helmholtz Centre for Infection Research (HZI) in Braunschweig and the German Center for Infection Research (DZIF) joined forces with scientists from Sanofi, a global health care company, and identified a new agent, which might potentially remedy these problems. The scientists just described this agent and its unique mechanism of action in the highly renowned scientific journal Science.

Mycobacterium tuberculosis is the main cause of tuberculosis. The treatment for drug-susceptible tuberculosis consists of the daily administration of multiple drugs for a minimum of six months. Lack of adherence to this regimen can result in treatment failure and the emergence of drug resistance. "Complexity and duration of the treatment are true issues and the main reasons for the development of resistant pathogens," says Prof Rolf Müller, who is the Executive Director and head of the Microbial Natural Substances department of the HIPS, an institution jointly sponsored by the HZI and Saarland University.

Consequently, there is an urgent need for new medications and therapeutic approaches to both fight the resistant pathogens, as well as to shorten the duration for the treatment of drug-susceptible organisms. Based on earlier reports, Müller, in collaboration with Prof Jacques Grosset from the Johns Hopkins University School of Medicine in Baltimore, and his colleagues from the HZI and Sanofi scientists, initially focused on the natural substance called griselimycin. The potential of this natural substance, was discovered in the 1960s. However, due to the success of other tuberculosis medications and its low efficacy in an infection model, the substance was not developed any further at the time.

"We resumed the work on this agent and optimised it such that it shows excellent activity in the infection model - even against multi-resistant tuberculosis pathogens," says Müller. In the course of their work, the scientists discovered that cyclohexylgriselimycin, a variant of griselimycin, is particularly effective against Mycobacterium tuberculosis, both in cells and in the animal model. Importantly, cyclohexylgriselimycin was effective when administered orally, which is key in tuberculosis treatment, non-orally available drugs are extremely burdensome to administer daily during the many months of treatment. Moreover, combining this substance with current TB antibiotics increases the efficacy compared to the antibiotic cocktail that is usually administered.

Scientists identify new agent to combat tuberculosis

Combination of bedaquiline and verapamil reduces side effects, improves outcomes for TB patients

In continuation of my update on Bedaquiline

While an effective treatment is available for combating multidrug-resistant tuberculosis, it carries serious side effects for patients. New research conducted at the Center for Tuberculosis Research at the Johns Hopkins University School of Medicine shows that lower doses of the toxic drug bedaquiline — given together with verapamil, a medication that's used to treat various heart conditions — can lead to the same antibacterial effects as higher toxic doses of bedaquiline. The combination of the two drugs could potentially shorten treatment time, reduce the side effects of bedaquiline and improve patient outcomes for those suffering from TB.

The study will be published in the January 2014 issue of Antimicrobial Agents and Chemotherapy. The lead author is William Bishai, M.D., Ph.D., co-director of the Center for Tuberculosis Research.

"Using a mouse model of tuberculosis, we have shown lower doses of bedaquiline together with verapamil have the same antibacterial effect as the higher toxic doses," says Shashank Gupta, Ph.D., a research fellow at Johns Hopkins. "A lower dose of bedaquiline will cause no or less severe side effects."

Two years ago, bedaquiline became the first drug in the last four decades to be approved by the U.S. Food and Drug Administration for the treatment of multidrug-resistant TB. The drug works by inhibiting an enzyme used by Mycobacterium tuberculosis to replicate and spread throughout the body. While it can be a lifesaving therapy against one of the world's deadliest diseases, bedaquiline can also cause serious side effects in the heart and liver. Therefore, strategies to reduce the dose of bedaquiline while retaining its antibacterial activity would provide significant benefits to patients.

"Shortening treatment regimens and reducing the required doses may be a promising strategy to reduce the incidence of bedaquiline-related adverse effects and thereby improve multidrug-resistant TB treatment outcomes," says Gupta.

Combination of bedaquiline and verapamil reduces side effects, improves outcomes for TB patients

Researchers uncover how malaria parasite becomes resistant to fosmidomycin drug

Researchers have uncovered a way the malaria parasite becomes resistant to an investigational drug. The discovery, at Washington University School of Medicine in St. Louis, also is relevant for other infectious diseases including bacterial infections and tuberculosis.

The study appears July 24 in Nature Communications.

Many organisms, including the parasite that causes malaria, make a class of molecules called isoprenoids, which play multiple roles in keeping organisms healthy, whether plants, animals or bacteria. In malaria, the investigational drug fosmidomycin blocks isoprenoid synthesis, killing the parasite. But over time the drug often becomes less effective.

"In trials testing fosmidomycin, the malaria parasite returned in more than half the children by the end of the study," said senior author Audrey R. Odom, MD, PhD, assistant professor of pediatrics. "We wanted to know how the parasite is getting around the drug. How can it manage to live even though the drug is suppressing these compounds that are necessary for life?"

Fosmidomycin, an antibiotic, is being evaluated against malaria in phase 3 clinical trials in combination with other antimalarial drugs.

Using next-generation sequencing technology, the research team compared the genetics of malaria parasites that responded to the drug to the genetics of malaria parasites that were resistant to it. With this approach, Odom and her colleagues found mutations in a gene called PfHAD1. With dysfunctional PfHAD1, malaria is resistant to fosmidomycin.

"The PfHAD1 protein is completely unstudied," Odom said. "It's a member of a larger family of proteins, and there are almost no biological functions assigned to them."

In malaria parasites, Odom's team showed that the PfHAD1 protein normally slows down the synthesis of isoprenoids. In other words, when present, PfHAD1 is doing the same job as the drug, slowing isoprenoid manufacturing. Since isoprenoids are necessary for life, it's not clear why the organism would purposefully slow down isoprenoid production.

Ref : http://www.nature.com/ncomms/2014/140724/ncomms5467/full/ncomms5467.html

Researchers uncover how malaria parasite becomes resistant to fosmidomycin drug

Multitarget TB drug could treat other diseases, evade resistance -- ScienceDaily

A drug under clinical trials to treat tuberculosis could be the basis for a class  of broad-spectrum drugs that act against various bacteria, fungal infections and parasites, yet evade resistance, according to a study. The team determined the different ways the drug SQ109 attacks the tuberculosis bacterium, how the drug can be tweaked to target other pathogens from yeast to malaria  and how targeting multiple pathways reduces the probability of pathogens becoming resistant.

Led by U. of I. chemistry professor Eric Oldfield, the team determined the different ways the drug SQ109 attacks the tuberculosis bacterium, how the drug  can be tweaked to target other pathogens from yeast to malaria -- and how targeting multiple pathways reduces the probability of pathogens becoming resistant. SQ109 is made by Sequella Inc., a pharmaceutical company. 

"Drug resistance is a major public health threat," Oldfield said. "We have to make new antibiotics, and we have to find ways to get around the resistance problem. And one way to do that is with multitarget drugs. Resistance in many cases arises because there's a specific mutation in the target protein so the drug will no longer bind. Thus, one possible route to attacking the drug resistance problem will be to devise drugs that don't have just one target, but
two or three targets."

Oldfield read published reports about SQ109 and realized that the drug would likely be multifunctional because it had chemical features similar to those found in other systems he had investigated. The original developers had identified one key action against tuberculosis -- blocking a protein involved in building the cell wall of the bacterium -- but conceded that the drug could have other actions within the cell as well since it was found to kill other bacteria and
fungi that lacked the target protein. Oldfield believed he could identify those actions  and perhaps improve upon SQ109. 

"I was reading Science magazine one day and saw this molecule, SQ109, and I thought, that looks a bit like molecules we've been studying that have multiple targets," Oldfield said. "Given its chemical structure, we thought that some of the enzymes that we study as cancer and antiparasitic drug targets also could be SQ109 targets. We hoped that we could make some analogs that would be more potent against tuberculosis, and maybe even against parasites.

More : http://pubs.acs.org/doi/abs/10.1021/jm500131s

Multitarget TB drug could treat other diseases, evade resistance

Mycobacterium tuberculosis is extraordinarily sensitive to killing by a vitamin C-induced Fenton reaction : Nature Communications : Nature Publishing Group

In a striking, unexpected discovery, researchers at Albert Einstein College of Medicine of Yeshiva University have determined that vitamin C kills drug-resistant tuberculosis (TB) bacteria in laboratory culture. The finding suggests that vitamin C added to existing TB drugs could shorten TB therapy, and it highlights a new area for drug design.

Dr. Jacobs and his colleagues observed that isoniazid-resistant TB bacteria were deficient in a molecule called mycothiol. "We hypothesized that TB bacteria that can't make mycothiol might contain more cysteine, an amino acid," said Dr. Jacobs. 

"So, we predicted that if we added isoniazid and cysteine to isoniazid-sensitive M. tuberculosis in culture, the bacteria would develop resistance. Instead, we ended up killing off the culture  something totally unexpected."

The Einstein team suspected that cysteine was helping to kill TB bacteria by acting as a "reducing agent" that triggers the production of reactive oxygen species (sometimes called free radicals), which can damage DNA.

"To test this hypothesis, we repeated the experiment using isoniazid and a different reducing agent vitamin C," said Dr. Jacobs. "The combination of isoniazid and vitamin C sterilized the M. tuberculosis culture. We were then amazed to discover that vitamin C by itself not only sterilized the drug-susceptible TB, but also sterilized MDR-TB and XDR-TB strains."

To justify testing vitamin C in a clinical trial, Dr. Jacobs needed to find the molecular mechanism by which vitamin C exerted its lethal effect. More research produced the answer: Vitamin C induced what is known as a Fenton reaction, causing iron to react with other molecules to create reactive oxygen species that kill the TB bacteria.

"We don't know whether vitamin C will work in humans, but we now have a rational basis for doing a clinical trial," said Dr. Jacobs. "It also helps that we know vitamin C is inexpensive, widely available and very safe to use. At the very least, this work shows us a new mechanism that we can exploit to attack TB.".....

Ref : http://www.einstein.yu.edu/news/releases/907/study-finds-vitamin-c-can-kill-drug-resistant-tb/


Mycobacterium tuberculosis is extraordinarily sensitive to killing by a vitamin C-induced Fenton reaction : Nature Communications : Nature Publishing Group

FDA Approves Sirturo to Treat Multi-Drug Resistant Tuberculosis

In continuation of my update on bedaquiline...

Sirturo is being approved under the FDA’s accelerated approval program, which allows the agency to approve a drug to treat a serious disease based on clinical data showing that the drug has an effect on a surrogate endpoint that is reasonably likely to predict a clinical benefit to patients. This program provides patients earlier access to promising new drugs while the company conducts additional studies to confirm the drug’s clinical benefit and safe use.

The FDA also granted Sirturo fast track designation, priority review and orphan-product designation. The drug demonstrated the potential to fill an unmet medical need, has the potential to provide safe and effective treatment where no satisfactory alternative therapy exists, and is intended to treat a rare disease, respectively.

Sirturo carries a Boxed Warning alerting patients and health care professionals that the drug can affect the heart’s electrical activity (QT prolongation), which could lead to an abnormal and potentially fatal heart rhythm. The Boxed Warning also notes deaths in patients treated with Sirturo. Nine patients who received Sirturo died compared with two patients who received placebo. Five of the deaths in the Sirturo group and all of the deaths in the placebo arm seemed to be related to tuberculosis, but no consistent reason for the deaths in the remaining Sirturo-treated patients could be identified.

Sirturo’s manufacturer, Janssen Therapeutics, will distribute the drug from a single source and will provide educational materials to help ensure the drug is used appropriately.

Sirturo’s safety and effectiveness were established in 440 patients in two Phase 2 clinical trials. Patients in the first trial were randomly assigned to be treated with Sirturo plus other drugs used to treat TB, or a placebo plus other drugs used to treat TB. All patients in the second trial, which is ongoing, received Sirturo plus other TB drugs. Both studies were designed to measure the length of time it took for a patient’s sputum to be free of M. tuberculosis (sputum culture conversion, or SCC).

FDA Approves Sirturo to Treat Multi-Drug Resistant Tuberculosis

Diospyrin inactivates a drug target for tuberculosis in new way

A compound from the South African toothbrush tree inactivates a drug target for tuberculosis in a previously unseen way. 

The compound under research, diospyrin (see below structure), binds to a novel site on a well-known enzyme, called DNA gyrase, and inactivates the enzyme. DNA gyrase is essential for bacteria and plants but is not present in animals or humans. It is established as an effective and safe drug target for antibiotics.

"The way that diospyrin works helps to explain why it is effective against drug-sensitive and drug-resistant strains of tuberculosis," said Professor Tony Maxwell from the John Innes Centre.

In traditional medicine the antibacterial properties of the tree are used for oral health and to treat medical complaints such bronchitis, pleurisy and venereal disease. Twigs from the tree are traditionally used as toothbrushes.

Most antibiotics originate from naturals sources, such as the soil bacteria Streptomyces. Antibiotics derived from plants are less common, but they are potentially rich sources of new medicines.

"Extracts from plants used in traditional medicine provide a source for novel compounds that may have antibacterial properties, which may then be developed as antibiotics," said Professor Maxwell.

Diospyrin inactivates a drug target for tuberculosis in new way

FDA Approves Sirturo to Treat Multi-Drug Resistant Tuberculosis

In continuation of my update on Sirturo

On Dec. 28, the U.S. Food and Drug Administration approved Sirturo (bedaquiline) as part of combination therapy to treat adults with multi-drug resistant pulmonary tuberculosis (TB) when other alternatives are not available.

Bedaquiline (also known as Sirturo, TMC207 or R207910 see structure) is an diarylquinoline anti-tuberculosis drug, which was discovered by Koen Andries and his team at Janssen Pharmaceutica. It was described for the first time in 2004 at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) meeting Late-Breaker Session, after the drug had been in development for over 7 years, and a trial of 47 patients showed that it is effective in the treatment of M. tuberculosis.

Multi-drug resistant TB occurs when M. tuberculosis becomes resistant to isonazid and rifampin, two powerful drugs most commonly used to treat TB. Sirturo is the first drug approved to treat multi-drug resistant TB and should be used in combination with other drugs used to treat TB. Sirturo works by inhibiting an enzyme needed by M. tuberculosis to replicate and spread throughout the body.

“Multi-drug resistant tuberculosis poses a serious health threat throughout the world, and Sirturo provides much-needed treatment for patients who have don’t have other therapeutic options available,” said Edward Cox, M.D., M.P.H, director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research. “However, because the drug also carries some significant risks, doctors should make sure they use it appropriately and only in patients who don’t have other treatment options.”

Sirturo is being approved under the FDA’s accelerated approval program, which allows the agency to approve a drug to treat a serious disease based on clinical data showing that the drug has an effect on a surrogate endpoint that is reasonably likely to predict a clinical benefit to patients. This program provides patients earlier access to promising new drugs while the company conducts additional studies to confirm the drug’s clinical benefit and safe use.

The FDA also granted Sirturo fast track designation, priority review and orphan-product designation. The drug demonstrated the potential to fill an unmet medical need, has the potential to provide safe and effective treatment where no satisfactory alternative therapy exists, and is intended to treat a rare disease, respectively.

Sirturo carries a Boxed Warning alerting patients and health care professionals that the drug can affect the heart’s electrical activity (QT prolongation), which could lead to an abnormal and potentially fatal heart rhythm. The Boxed Warning also notes deaths in patients treated with Sirturo. Nine patients who received Sirturo died compared with two patients who received placebo. Five of the deaths in the Sirturo group and all of the deaths in the placebo arm seemed to be related to tuberculosis, but no consistent reason for the deaths in the remaining Sirturo-treated patients could be identified.

FDA Approves Sirturo to Treat Multi-Drug Resistant Tuberculosis

Stroke drug kills bacteria that cause ulcers and tuberculosis

Now researchers  found that, a compound called ebselen (see structure) effectively inhibits the thioredoxin reductase system in a wide variety of bacteria, including Helicobacter pylori which causes gastric ulcers and Mycobacterium tuberculosis which causes tuberculosis. Thioredoxin and thioredoxin reductase proteins are essential for bacteria to make new DNA, and protect them against oxidative stress caused by the immune system. Targeting this system with ebselen, and others compounds like it, represents a new approach toward eradicating these bacteria.

Building on previous observations where ebselen has shown antibacterial properties against some bacteria, Holmgren and colleagues hypothesized that the bacteria sensitive to ebselen relied solely on thioredoxin and thioredoxin reductase for essential cellular processes. They investigated this by testing it on strains of E. coli with deletions in the genes for thioredoxin, thioredoxin reductase and the glutaredoxin system. They found that strains with deletions in the genes coding for glutaredoxin system were much more sensitive than normal bacteria. Researchers further tested ebselen againstHelicobacter pylori andMycobacterium tuberculosis, which both naturally lack the glutaredoxin system and are frequently resistant to many commonly used antibiotics, and found both to be sensitive to ebselen.

"As rapidly as these organisms evolve, we need new drugs sooner rather than later," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. "The fact that these scientists have found a new target for killing some of the most resistant bacteria is great news, but the fact that we already have at least one drug which we could possibly use now makes the news even better."

Ref : http://www.fasebj.org/content/early/2012/12/17/fj.12-223305

Stroke drug kills bacteria that cause ulcers and tuberculosis

Beating Drug-Resistant TB.....

An antibiotic produced naturally by common soil bacteria kills Mycobacterium species that cause various human diseases, including tuberculosis (TB), according to a report published Monday (September 17) in EMBO Molecular Medicine. The antibiotic even kills drug-resistant strains that escape current TB treatments.

“I seldom get so tickled when I read a paper,” said William Jacobs, a microbiologist and immunologist at the Albert Einstein College of Medicine in New York, who did not participate in the research. The emergence of multidrug resistant strains of Mycobacterium tuberculosis “is a big problem,” he said. “This could be a godsend.”

Tuberculosis infections are commonly treated with a mixture of antibiotics, including one called isoniazid, which Jacobs described as “the cornerstone of TB therapy.”  Unfortunately, the most common drug-resistant strains of M. tuberculosis are isoniazid-resistant, he said.

Many researchers, including Stewart Cole, chair of the microbial pathogenesis department at the École Polytechnique Fédérale de Lausanne in Switzerland, have thus been searching for new M. tuberculosis-killing drugs. “In the past we’ve been working a lot on TB drug discovery using target-based approaches… [but] this has been spectacularly unsuccessful,” said Cole. So instead, he and his colleagues looked back over decades of academic literature searching for reports of natural compounds with M. tuberculosis-killing activity.

They found pyridomycin (see above structure). First described in the 1950s, the drug was reportedly produced by the bacteria Streptomyces pyridomyceticus and Dactylosporangium fulvum. Surprisingly, little was known about pyridomycin—perhaps, Cole suggested, because isoniazid was discovered around the same time and simply stole the limelight.

Cole’s team grew cultures of D. fulvum bacteria, figured out how to isolate and purify pyridomycin, and then showed that the drug was indeed capable of killing M. tuberculosis, as well as many otherMycobacterium species, in culture.

This indiscriminate Mycobacterium-killing ability is a bonus, said Cole. “One of the problems with isoniazid is that it only works against TB,” he said. “If pyridomycin makes it into the clinic, it could have applications in leprosy or Buruli ulcer or atypical mycobacterial infections that can occur in cystic fibrosis patients.”

The team went on to identify the bactericidal target of pyridomycin—a protein called inhA, which is involved in synthesis of bacterial cell wall components. As it happens, inhA is the same protein targeted by isoniazid, but there is a difference in the two drugs’ mechanisms. While isoniazid is a pro-drug that requires activation by an intracellular enzyme called KatG before it can bind to inhA, pyridomycin binds inhA directly.

This is an important distinction, explained Valerie Mizrahi, director of the Institute of Infectious Disease and Molecular Medicine at Cape Town University, South Africa, who was not involved in the study. The overwhelming majority of drug resistance mutations in M. tuberculosis occur in the KatGgene, she explained, and such mutant strains should not be resistant to pyridomycin. Indeed, the team showed that clinical isolates of isoniazid-resistant M. tuberculosis carrying KatG mutations were killed effectively by pyridomycin. “The efficacy against drug resistant forms of M. tuberculosis is particularly encouraging,” Mizrahi said.

There is, however, much to be done before pyridomycin can be used in the clinic. “We would [need to] test that it works in animal models and that it is safe and doesn’t have any side effects,” said Cole. “That will take a couple of years.”

“It’s a long journey,” agreed Mizrahi, “but the big plus is that they don’t really need to validate inhA as a drug target because inhA is already the most well validated drug target out there… [so] it has got a good head start.”

Ref : http://onlinelibrary.wiley.com/doi/10.1002/emmm.201201689/abstract

New Drug, Bedaquiline to Tackle Resistant TB

Johnson & Johnson said that it is seeking U.S. approval for the first new type of medicine to fight deadly tuberculosis in more than four decades.

The experimental drug, called bedaquiline (discovered by Koen Andries, see structure), also would be the first medicine specifically for treating multi-drug-resistant tuberculosis. That's an increasingly common form in which at least two of the four primary TB drugs don't work.

Mode of action : Bedaquiline affects the proton pump for ATP synthase, which is unlike the quinolones, whose target is DNA gyrase

Tuberculosis, caused by bacterial infection of the lungs and other body areas, is the world's No. 2 killer of adults among infectious diseases.

J&J's Janssen Research & Development unit created the drug, which was tested in several hundred patients with multidrug-resistant tuberculosis in two mid-stage studies lasting for six months. Some patients were studied for about 1 1/2 years.

The company this fall is to begin late-stage testing that will compare bedaquiline to dummy pills over nine months in about 600 patients; each will also take six other drugs that are the standard treatments for tuberculosis. That study is aimed at seeing whether treatment for resistant tuberculosis can be reduced to nine months from the current 18 to 24 months recommended by the World Health Organization.

Roughly one-third of the world's population is estimated to be infected with the bacteria causing tuberculosis. It remains latent in most people for many years but can be activated by another infection or serious health problem.

TB is rare in the U.S. but kills about 1.4 million people a year worldwide, with about 150,000 of those succumbing to the increasingly common multidrug-resistant forms.

Janssen's head of infectious diseases, Dr. Wim Pays, said the company will also apply for approval of bedaquiline in other countries where TB is very common.

The disease is a serious problem in developing countries because it takes so long to cure and many patients stop taking their pills once they begin to feel better. That helps bacteria still alive in the patient to develop resistance to the medicines already taken, making future treatment much more difficult.

Ref : http://www.inpharm.com/news/173302/janssen-submits-tuberculosis-pill-fda