Showing posts with label Artemisinin. Show all posts
Showing posts with label Artemisinin. Show all posts

Friday, July 09, 2010

Gates grant funds production of genetically engineered malaria drug

A Cambodian soldier offers blood for a malaria test near the Cambodian and Thai border, where efforts are underway to eliminate a drug-resistant strain of falciparum malaria (TANG CHHIN SOTHY/AFP/GETTY IMAGES)

July 8, 2010

Posted by Kristi Heim
Seattle Times (Washington State, USA)


The Institute for OneWorld Health, a San Francisco-based nonprofit, said it has received $10.7 million from the Gates Foundation to begin commercial production of a key ingredient for malaria treatment.

In a partnership with drug company Sanofi-Aventis, the institute will use the Gates grant to prepare for large-scale production and commercialization of semi synthetic artemisinin by 2012.

Semi synthetic artemisinin is produced by a combination of genetic engineering and synthetic chemistry.

Artemisinin, the standard treatment recommended for malaria, is derived from artemisia, an herb found in Chinese medicine from the leaves of the wormwood tree.

While the parasite that causes the mosquito-borne disease has developed resistance to traditional drugs such as chloroquine, artemisinin in combination with other drugs is considered to be the most effective medication and credited with raising recovery rates globally.

The problem is its cost. Labor intensive extraction drives the price up and out of reach of most people in malaria prone areas such as sub-Saharan Africa.

This scientific paper describes the process, and this article offers a plain English translation of the project to use genetic engineering techniques to create microbes that can mass-produce artemisinin. (The University of Washington is also studying artemisinin's potential in cancer prevention.)

But even a more stable supply may not fully solve the problem of drug resistance when it comes to malaria. U.S. health officials say resistance to artemisinin is spreading.

The World Health Organization (WHO) warned last year that parasites resistant to artemisinin had emerged along the border between Cambodia and Thailand.

The Gates Foundation gave the Institute for OneWorld Health a five-year $42.5 million grant in 2004 to establish and validate a manufacturing process to make artemisinin-type drugs more affordable.

Monday, December 28, 2009

New form of malaria threatens Thai-Cambodia border

This Aug. 27, 2009 photo shows stacks of expired malaria medication in an NGO's village office near Pailin, Cambodia. Malaria parasites in the Thai-Cambodia area of Pailin, Cambodia have become resistant to artemisinin-based therapies according to Non Governmental Agencies working in the region. If this drug stops working, there's no good replacement to combat a disease that kills 1 million annually. As a result, earlier this year international medical leaders declared resistant malaria here a health emergency. (AP Photo/David Longstreath)
This Aug. 28, 2009 photo shows malaria researcher Sornsuda Setaphan preparing blood samples at the hospital in Pailin, Cambodia. Malaria parasites in the Thai-Cambodia area of Pailin, Cambodia have become resistant to artemisinin-based therapies according to Non Governmental Agencies working in the region. If this drug stops working, there's no good replacement to combat a disease that kills 1 million annually. As a result, earlier this year international medical leaders declared resistant malaria here a health emergency. (AP Photo/David Longstreath)
This Aug. 29, 2009 photo shows Cambodian Hoeun Hong Da, 13, still recovering from an attack of malaria, smiling as he arrives home with a new mosquito resistant bed net as he arrives at O'treng village on the outskirts of Pailin, Cambodia. This spot on the Thai-Cambodian border is home to a form of malaria that keeps rendering one powerful drug after another useless. This time, scientists have confirmed the first signs of resistance to the only affordable treatment left in the global medicine cabinet for malaria: Artemisinin. If this drug stops working, there's no good replacement to combat a disease that kills 1 million annually. As a result, earlier this year international medical leaders declared resistant malaria here a health emergency. (AP Photo/David Longstreath)
This Aug. 29, 2009 photo shows Chhay Meth, 9, suffering through an attack of malaria at the family's home in O'treng village on the outskirts of Pailin, Cambodia. This spot on the Thai-Cambodian border is home to a form of malaria that keeps rendering one powerful drug after another useless. This time, scientists have confirmed the first signs of resistance to the only affordable treatment left in the global medicine cabinet for malaria: Artemisinin. If this drug stops working, there's no good replacement to combat a disease that kills 1 million annually. As a result, earlier this year international medical leaders declared resistant malaria here a health emergency. (AP Photo/David Longstreath)

2009-12-28
By MARGIE MASON and MARTHA MENDOZA, Associated Press Writers
Associated Press

EDITOR'S NOTE: Once curable diseases such as tuberculosis and malaria are rapidly mutating into aggressive strains that resist drugs. The reason: The misuse of the very drugs that were supposed to save us has built up drug resistance worldwide. Second in a five-part series.

PAILIN, Cambodia (AP) - O'treng village does not look like the epicenter of anything.

Just off a muddy, rutted-out road, it is nothing more than a handful of Khmer-style bamboo huts perched crookedly on stilts, tucked among a tangle of cornfields once littered with deadly land mines.

Yet this spot on the Thai-Cambodian border is home to a form of malaria that keeps rendering one powerful drug after another useless. This time, scientists have confirmed the first signs of resistance to the only affordable treatment left in the global medicine cabinet for malaria: Artemisinin.

If this drug should stop working, there would be no good replacement to combat a disease that kills 1 million people annually. As a result, international medical leaders declared this year that resistant malaria here is a health emergency.

"This is not business as usual. It's something really special, and it needs a real concerted effort," said Dr. Nick White, a malaria expert at Mahidol University in Bangkok, who has spent decades trying to eradicate the disease from Southeast Asia. "We know that children have been dying in Africa _ millions of children have died over the past three decades _ and a lot of those deaths have been attributed to drug resistance. And we know that the drug resistance came from the same place."

Malaria is just one of the leading killer infectious diseases battling back in a new and more deadly form, the AP found in a six-month look at the soaring rates of drug resistance worldwide. After decades of the overuse and misuse of antibiotics, diseases like malaria, tuberculosis and staph have started to mutate. The result: The drugs are slowly dying.

Already, The Associated Press found, resistance to malaria has spread faster and wider than previously documented. Dr. White said virtually every case of malaria he sees in western Cambodia is now resistant to drugs. And in the Pailin area, patients given artemisinin take twice as long as those elsewhere to be clear of the parasite _ 84 hours instead of the typical 48, and sometimes even 96.

Mosquitoes spread this resistant malaria quickly from shack to shack, village to village, eventually country to country.

And so O'treng, with its 45 poor families, naked kids, skinny dogs and boiling pots of rice, finds itself at the epicenter of an increasingly desperate worldwide effort to stop a dangerous new version of an old disease.

Bundled in a threadbare batik sarong, 51-year-old Chhien Rern, one of O'treng's sick residents, sweats and shivers as a 103-degree fever rages against the malaria parasites in her bloodstream.

Three days ago Chhien Rern started feeling ill while looking for work in a neighboring district. So she did what most rural Cambodians do: She walked to a little shop and asked for malaria medicine. With no prescription, she was handed a packet of pills; she is unsure what they were.

"After I took the drugs, I felt better for a while," she says. "Then I got sick again."

The headaches, chills and fever, classic symptoms of malaria, worsened. Chhien Rern's daughter persuaded her to take a motorbike taxi past washed out bridges and flooded culverts to the nearest hospital in Pailin, a dirty border town about 10 miles (16 kilometers) from O'treng.

Doctors say there is a good chance that Chhien Rern was sold counterfeit drugs.

People generate drug resistant malaria when they take too little medicine, substandard medicine or _ as is all too often the case around O'treng _ counterfeit medicine with a pinch of the real stuff. Once established, the drug-resistant malaria is spread by mosquitoes. So one person's counterfeit medicine can eventually spawn widespread resistant disease.

Yet in most parts of the world, people routinely buy antimalarials over the counter at local pharmacies and treat themselves.

A recent study out of neighboring Laos found 88 percent of stores selling artemisinin-based drugs, the same ones scientists are desperately trying to preserve, were actually peddling fakes. Worse, nearly 15 percent of the counterfeits were laced with small hints of artemisinin, which could prompt resistance. The researchers found indications that some were made in China, feeding smugglers' routes that snake through Myanmar and into Laos, Thailand, Cambodia and Vietnam.

The counterfeits, along with outdated drugs, are jumping continents. In Africa, where malaria is endemic in 45 countries, the fake drug industry is thriving. A 2003 World Health Organization survey found between 20 percent and 90 percent of antimalarials randomly purchased in seven African countries failed quality testing, depending on the type of drug.

WHO and Interpol formed a task force three years ago to try to stop counterfeiters, seizing millions of fake malaria, tuberculosis, HIV and other pills in Southeast Asia and Africa. But officials say the work is only as good as the countries' legal systems.

"One of the problems is that there's not really any enforcement, so what happens when they find a drug that's counterfeit or substandard?" says David Sintasath, a regional epidemiologist at the nonprofit Malaria Consortium in Bangkok. "The policy is to take it away from them. That's good until the next month when they get their next shipment, right?"

Countless unlicensed shops in Cambodia sell artesunate, a single-drug therapy that has been banned in the country. Artesunate, a modified version of artemisinin derived from a Chinese herb, has been hailed as miracle treatment worldwide because it works so well with so few side effects. But Cambodian surveys have shown that many patients take artesunate alone instead of mixing it with another antimalarial drug, making it easier for resistance to build.

"The drug has been around for a long time and misused for a long time, and this is all encouraging the parasite to develop resistance," says Dr. Delia Bethell, of the U.S. Armed Forces Research Institute of Medical Science, whose research has been at the forefront of identifying emerging resistance on the border.

Back in western Cambodia a few miles from O'treng village, shopkeeper Nop Chen turns a flashlight on a glass case full of drugs he hawks from inside his cramped roadside house. He digs through the many boxes and produces two different types of artemisinin-based antimalarials. Both lack the full amount of a second required medication, mefloquine, necessary to treat the strain of malaria in the area and ward off more resistance.

But Nop Chen, a former Khmer Rouge medic, points to a small Cambodian seal on the boxes and says he feels confident the drugs are the real deal. Still, he acknowledges he is not licensed to sell the pills and he is unsure where they originated.

"I'm not concerned because it's got the sticker and the stamp," he says, squinting at the Khmer script on the labels. "Because of the logo, I trust it to not be fake; it was made in Cambodia."

Walk past O'treng's cluster of sagging huts, cross another cornfield and hike a twisted mile (1 1/2 kilometer) on a dirt track to a wooden shack where a string of smoke is curling through the wooden floor planks in a largely futile effort to keep mosquitoes away. It is here that skinny 13-year-old Hoeun Hong Da wakes up on the floor nauseous and burning with fever.

Hong Da recovered from malaria two months ago, but now the dizziness and headaches are back. He has been sickened by the disease six or seven times in his short life _ too many to remember. He knows that if he does not get to a hospital soon, he could die.

With no new treatments in the pipeline, normally reserved scientists are quick to use words like "disaster" or "catastrophe" when asked what might happen if they do not contain the disease that is ravaging young Hong Da before it spreads to Africa. There, malaria already kills an estimated 2,000 kids every day.

For the past 50,000 years the malaria parasite has been evolving, and migrating, alongside humans. It moves within the huts of O'treng, and into neighboring towns when men like Hong Da's father and older siblings float from job to job.

Some work is close enough for them to return home at night, but other jobs keep them away for stretches of time. They sleep in tight rows, sweating and weary, in disintegrating bamboo huts with workers who are also traveling, and possibly infected with malaria.

The concept of containing drug resistance has never been tried before. Scientists wonder: How do you control the spread of a resistant parasite transmitted by mosquitoes that bite people who live and work in infested jungle areas, then scatter in all directions, all the time?

This area, the former stronghold of the murderous Khmer Rouge, has a notorious history. Burmese migrant workers who once mined rubies and sapphires in these now deforested hills are believed to have helped transport strains resistant to the drug chloroquine back to Myanmar a half-century ago. From there it spread to India and later over to Africa until the drug was useless worldwide.

A decade later, history repeated itself when resistance to the drug sulfadoxine-pyrimethamine followed the same path.

Now, in western Cambodia, scientists are worried because the artemisinin-based drugs are taking longer than usual to kill the parasites. This year, an army of aid agencies and experts from the WHO began racing to this impoverished corner on the Thai-Cambodian border to divide up a $22.5 million grant from the Bill & Melinda Gates Foundation, aimed at stopping this virulent new strain.

Grants haven't stopped lines of Cambodians, sick or not, from queuing up every morning at Thailand's border, charging past the checkpoints in search of work or goods. Some may carry resistant strains in, others may bring them home.

Grants have not stopped the parasite from spreading in the O'treng area, despite widespread bednet distribution, awareness campaigns and enhanced surveillance systems. Some scientists say the only sure way to fix the problem is to eradicate malaria entirely from western Cambodia.

"It's really dangerous," says Dr. Rupam Tripura, who is conducting a study in Pailin for the Wellcome Trust-Mahidol University-Oxford Tropical Medicine Research Program. "What will happen to the mosquitoes? Can you kill those living in the jungle? No. So you cannot kill the strain."

If O'treng is the epicenter of this emerging disease, Phoun Sokha is the point man aimed at controlling it.

At 47, Phoun Sokha is the village malaria worker who lives at the mouth of the hamlet and proudly displays an orange plastic kit that resembles a tackle box.

Phoun Sokha is serious about his packets of medicine and his rapid tests to prick blood from sick villagers' fingers to determine whether they have malaria, and if so, what type. He makes sure patients are taking their free medicines and checks to see if they are improving. If not, Phoun Sokha can even arrange transportation to the hospital.

But treating O'treng's malaria patients can be frustrating.

"Some of the patients, when they went to the hospital, after one month, maybe they get malaria again," he says.

Today Hong Da, the village boy who has fought malaria so many times before, heads home from the hospital after a few days of treatment. He clutches a new mosquito net he hopes will prevent yet another infection. Together, the recovering boy and his weathered mom shuffle past sick neighbor Chhien Rern's shack before disappearing among the tassels of the cornfield toward their home.

But all is not well.

Under a tattered quilt, Hong Da's 9-year-old sister Hoeun Chhay Meth is curled on a thin mattress atop the wooden floor inside the family's open-air home.

She had malaria alongside her brother two months ago. They share a mosquito net that she burned a hole in when she stayed up one night reading by the light of a makeshift candle. Her brother thinks that is how the mosquitoes infected them.

"Very afraid of dying," says Chhay Meth, who has started taking medicine provided by the village malaria worker. "I feel worse than before. I cannot walk myself or stand up by myself and cannot eat well."

Hong Da understands. He gently lifts his little sister's limp body, scooping her up, his strength returning. Chhay Meth reaches weakly for her mother.

Like her big brother, this child does not know about counterfeit drugs or antimalarials.

She only knows she is sick. And the medicines do not seem to work as well any more in this little village she calls home.
____
Martha Mendoza is an AP national writer based in Mexico City. Margie Mason is an AP medical writer who reported from Cambodia while on a fellowship from The Nieman Foundation at Harvard University.

Tuesday, January 27, 2009

Spread of Malaria Feared as Drug Loses Potency

Malaria patients in the intensive care ward of the provincial hospital in Battambang, Cambodia. (Photo: Thomas Fuller/International Herald Tribune)

January 27, 2009
By THOMAS FULLER
The New York Times

TASANH, Cambodia — The afflictions of this impoverished nation are on full display in its western corner: the girls for hire outside restaurants, the badly rutted dirt roads and the ubiquitous signs that warn “Danger Mines!”

But what eludes the naked eye is a potentially graver problem, especially for the outside world. The parasite that causes the deadliest form of malaria is showing the first signs of resistance to the best new drug against it.

Combination treatments using artemisinin, an antimalaria drug extracted from a plant used in traditional Chinese medicine, have been hailed in recent years as the biggest hope for eradicating malaria from Africa, where more than 2,000 children die from the disease each day.

Now a series of studies, including one recently published in The New England Journal of Medicine and one due out soon, have cemented a consensus among researchers that artemisinin is losing its potency here and that increased efforts are needed to prevent the drug-resistant malaria from leaving here and spreading across the globe.

“This is something we can’t just slide under the carpet,” said R. Timothy Ziemer, a retired admiral in the United States Navy who heads the President’s Malaria Initiative, the $1.2 billion program started by the Bush administration three years ago to cut malaria deaths in half in the countries affected worst.

Admiral Ziemer met with Thai and Cambodian officials last month to assess the resistance problem, which affects the same drugs used by the malaria initiative in Africa.

“We feel that we not only have to beat the drum but shake the cage: guys, this is significant,” he said.

Though the studies show relatively early signs of resistance to artemisinin, the drugs were judged to have failed in only two patients in the recently published study. Even they were eventually cured.

But malaria experts note that several times in the past, this same area around the Thai-Cambodian border appears to have been a starting point for drug-resistant strains of malaria, starting in the 1950s with the drug chloroquine.

Introduced immediately after World War II, chloroquine was considered a miracle cure against falciparum malaria, the deadliest type. But the parasite evolved, the resistant strains spread, and chloroquine is now considered virtually useless against falciparum malaria in many parts of the world, including sub-Saharan Africa.

It took decades for this resistance to spread across the world, so by the same token artemisinin-based drugs are almost sure to be useful for many years to come.

To protect against artemisinin resistance, the global health authorities are trying to assure that it is sold only as a combination pill with other antimalaria medicines that linger longer in the blood, mopping up any artemisinin-resistant parasites.

The two most recent tests showing artemisinin resistance were done with pills that had no combination drug. But if resistance spreads, there are no new drugs to take the place of artemisinin-based combinations and no immediate prospects under development.

“This could spread in any direction; we have to make sure it doesn’t,” said Pascal Ringwald, malaria coordinator at the World Health Organization, who three years ago led a study of drug resistance in Cambodia and is co-author of a coming study on the subject. “We know it’s not yet in Bangladesh,” he said. “It’s not yet in India.”

Scientists have documented how malarial parasites that were resistant to chloroquine in the 1950s spread across Thailand, Burma, India and over to Africa, where a vast majority of the nearly one million annual malaria-related deaths occur.

To prevent a recurrence with artemisinin therapies, the United States has put aside political considerations and approved a malaria monitoring center in military-run Myanmar, formerly Burma. The Bill and Melinda Gates Foundation, one of the largest donors to malaria research, is giving $14 million to the Thai and Cambodian governments to help pay for a containment program.

That program includes efforts to supply the area with mosquito nets, a screening program for everyone living in affected areas and follow-up visits by health workers to assess the effectiveness of the drugs, said Dr. Duong Socheat, director of Cambodia’s National Malaria Center. On the Thai side of the border, the government has “motorcycle microscopists” who take blood samples from villagers and migrant workers, analyze them on the spot and distribute antimalaria drugs.

But some experts would like to see an even more aggressive approach.

“Many of us think this should be treated on the same order as SARS,” said Col. Alan J. Magill, a researcher at the Walter Reed Army Institute of Research in Maryland. “This should be a global emergency that is addressed in a global fashion.” SARS, the respiratory disease that spread rapidly through Asia and beyond in 2003, killed more than 700 people.

The falciparum parasite is one of four types of malaria and by far the most virulent. It enters the bloodstream through a mosquito bite, and after incubating about two weeks, it multiplies and takes over red blood cells. There it causes fever, chills, headaches and nausea, among other symptoms. If untreated, the infected cells can block blood vessels and fatally cut off blood supply to vital organs.

The recent studies show that artemisinin-based drugs are becoming less effective in removing the parasite from the bloodstream. While a few years ago it took the drugs 48 hours to clear the bloodstream of parasites, it now can take 120 hours.

“What our study demonstrates is that therapy for some patients fails — the malaria goes away and comes back,” said Lt. Col. Mark M. Fukuda, a United States Army doctor whose study was published in The New England Journal of Medicine in December.

Different regions rely on different artemisinin combinations. The Cambodian government recommends that artemisinin be combined with mefloquine, which was developed by the American military and is known commercially as Lariam. Artemether, a derivative of artemisinin, is often combined with another antimalarial drug, lumefantrine. This was recently judged to be the most effective combination in a study of children in Papua New Guinea.

The same combination is also expected to be approved for sale in the United States soon, marketed by Novartis and mainly intended for people traveling overseas or for those who arrive in the United States with malaria.

The mosquito responsible for transmission of malaria is still endemic in the United States. But modern housing, better access to health care and the use of insecticides have virtually eradicated the disease in wealthier countries.

Here in Tasanh, a village 20 miles east of the Thai border, Dr. Fukuda and a team of researchers work in what is euphemistically called a more challenging environment. Tasanh is served by a dirt road and has no running water and no public supply of electricity.

In a small, spartan clinic, Chet Chen, an 18-year-old malaria patient, lies listlessly on an old metal-framed bed next to a sample of his urine in a used water bottle. The male nurse who examines blood samples is out helping to fix the weed whacker, which has broken.

In a small but newer annex to the clinic, Dr. Fukuda and his researchers work in a trilingual environment — Khmer (Cambodian), Thai and English — that sometimes sows confusion.

Americans in the clinic recently chuckled when a Thai researcher described a patient as having a “hot body” — a literal translation of “fever” in Thai, but one that evoked nightclub images.

Dr. Fukuda calls this region of Cambodia the “canary in the coal mine” for drug resistance.

In the past, migrant workers in plantations and gem mines are believed to have helped spread drug-resistant strains westward. A history of civil unrest, counterfeit drugs and a weak and underfinanced government has made it difficult to control malaria. In the case of chloroquine, preventive use of the drug — including putting it in table salt to protect a wide swath of the population — might have actually encouraged resistance to the drug, Dr. Fukuda and others say.

It was not until the 1990s that mefloquine, the American army drug, was combined with artemisinin, made from a Chinese herb.

Artemisinin-based combinations turned out to be fast-acting and seemed to slow transmission of the disease, said Dr. John MacArthur, an infectious disease expert with the United States Agency for International Development in Bangkok.

Dr. MacArthur and others say resistance to malaria drugs is a natural consequence of widespread use of the drug. “In the case of malaria, it’s the Darwinism of the parasite,” he said. “It likes to survive.”

Still, some researchers remain concerned about sending the wrong message to the public about the efficacy of artemisinin-based drugs.

“This is not the death knell of artemisinin,” said Dr. Nicholas White, a malaria expert who is chairman of a joint research program between Oxford University and Mahidol University in Thailand. “The drug still works in Cambodia, maybe not as well as before.”

But given the history of drug failures here, there appears to be a consensus on the solution.

“Get rid of all malaria from Cambodia,” Dr. White said. “Eradicate it. Eliminate it.”

Tuesday, November 18, 2008

Malaria Developing Worrisome Resistance

By Chiep Mony, VOA Khmer
Original report from Phnom Penh
17 November 2008



Cambodia’s western provinces have been developing a resistance to the only anti-malaria medication the government uses, a worried health official said Monday.

“I’m worried so much about malaria,” said Duong Socheat, director of the National Malaria Center. “Artemisinin is the No. 1 drug. Its ability is decreasing.”

The National Malaria Center had taken measures to cure malaria outbreaks, including the examination of malaria resistant to the drug. The center also provides education to villagers to use the drug properly and urges people to sleep under mosquito nets.

Cambodia began using the drug in 2000. Now it is used “100 percent” in state hospitals. Resistance to the drug began showing up around 2005, Duong Socheat said.

This year, the government used 3.6 million tablets of the drug, he said. Some of the medication was provided by the Chinese government, he said.

About 70 people nationwide have died from malaria so far this year, he said.

“If malaria becomes resistant to artemisinin,” he said, “gradually, more patients of malaria will die.”