A new pill cures preschoolers of a parasitic worm. Delivering it could be a challenge

When Dr. Isaac Chikwanha was a kid in Zimbabwe, he got schistosomiasis.

At the time, he didn't think about the cause of this parasitic disease: a worm that penetrates your skin and takes up residence in your blood vessels. And he didn't worry about short-term health consequences – such as blood in your urine – and he didn't know about the long-term consequences when the disease goes untreated, including organ damage and reduced learning ability.

Instead, as a 7-year-old, he thought of it as a point of pride.

"Getting schistosomiasis – getting blood in your urine – is considered a rite of passage because it means you're old enough to go and play in the river body and come back home alive," says Chikwanha, explaining that people can get infected when swimming or wading into rivers or lakes that have been contaminated with the parasite. "I think almost everyone who grew up in rural Africa had schistosomiasis at one point or the other."

He says it's so common that in some communities it is thought of as male menstruation. "Having blood in urine for boys is seen as a sign of maturity," he says. "If you haven't, you are not a man yet."

Worldwide more than 200 million people have schistosomiasis – the vast majority in Africa. But the good news is that, since the 1970s, there's been a highly effective treatment: a pill called praziquantel.

Chikwanha says he can't recall if he took it but figures he must have since he didn't have ongoing symptoms.

But there's one thing he's certain of now that he's a doctor: There's a major gap in conquering the disease, because the medication is designed only for school-age children and adults. Nobody knows exactly how many preschoolers have schistosomiasis but experts estimate that 50 million preschoolers are at risk but lack a good treatment option.

Of course, there's a hack: Crushing the current pill into a smaller dose. However, Chikwanha says, even breaking a pill in half or third or quarters doesn't guarantee an appropriate dose for a preschooler.

"It gets complicated," he says. And crushing raises another problem – when the pill is mixed with water rather than swallowed, it has a strong bitter taste, although adding syrup can help. So the reality is that many little kids are left untreated.

Chikwanha, a senior director at the Global Health Innovative Technology Fund in Japan, says these youngsters represent a "neglected population" with a neglected tropical disease.

Now that's about to change.

After more than a decade of work, a version of praziquantel designed specifically for preschoolers is on the cusp of becoming a reality. The Pediatric Praziquantel Consortium, a team of public and private partners, has developed a pill that dissolves in the mouth without a bitter taste and is the right dosage for the preschool population. Earlier this month, the World Health Organization gave its stamp of approval to this new pill, adding the medication to its list of prequalified medicines which have been assessed for quality, safety and efficacy.

But there are two major stumbling blocks: Who will pay for the medication? And how will this new treatment get to the children who need it?

"We are so close and so far," says Amadou Garba Djirmay, who oversees schistosomiasis efforts at the WHO. "So close because the medicine is available and so far because the funding for procurement and the system for procurement is not in place."

Why this new pill won't be donated

For more than a decade, Merck KGaA, Darmstadt, Germany – the pharmaceutical company that makes praziquantel – has donated hundreds of millions of tablets each year to treat school-age kids with schistosomiasis.

The same company helped develop the treatment for preschool-aged kids. But this new pill won't be donated.

The Pediatric Praziquantel Consortium's plan is to sell the pill at cost. The idea isn't that patients would have to pay but that ministries of health, international organizations and nonprofits would cover the cost.

The pills will be produced by local manufacturers – so far one is based in Brazil and another in Kenya – who will sell the pills. While the price is still being worked out, the consortium says it will be as low as possible, covering only the cost of production. The pharmaceutical companies that were involved in the development of the new formulation and did all the clinical testing, including Merck KGaA, are writing off those expenses as a donation and no fees were involved for the tech transfer to the local companies.

Why the change?

The donation model, says the consortium, means that countries must depend on a commitment from the manufacturer or benefactors, who are often from another country. The donated pills might not fully address the needs in a particular country – and donors can, of course, change their priorities.

The consortium says this new fee-based approach is a revolutionary one. Chikwanha, whose fund in Japan helped support the development of the preschool version of praziquantel and supports this new model, thinks it could spur more investment in developing new drugs. He says the idea that a company could sell – rather than donate – a medicine is like "a light at the end of the tunnel."

"This is a very significant moment," he says, since medications for neglected tropical diseases are typically donated to countries in need, typically by the drug manufacturer.

However, he acknowledges the exact details of this new model and who will pay are still being worked out. He hopes that countries will marshal the resources needed to buy the medications. But he says there are also efforts by the consortium to convince international organizations and local philanthropies to pay. "This is a paradigm shift. So whenever there's that kind of shift, it takes time," he says.

But Garba Djirmay, of WHO, is worried. WHO is working to organize funder meetings "but for the moment, there is no commitment," he says. "The final access of preschool-aged children is really a challenge."

He notes that the adult version of the schistosomiasis pill is not donated and governments and charities haven't stepped forward to purchase all the doses needed for adults. "Less than 30% of the adults in need of treatment have access to the medicine because it's not donated," he says. He worries something similar could happen for preschoolers.

Beatrice Greco, the head of access at Merck KGaA's Global Health Institute, is more optimistic. She believes that countries will find the money since battling schistosomiasis is a key pillar in child health. The disease is capable of worsening anemia and malnutrition as well as reducing academic performance and the immune response to vaccines. Addressing schistosomiasis can help fight a whole range of other health concerns.

"There's no question about vitamin A being bought, there's no question about vaccines being bought," she says. "Countries have to take the leadership here to make sure that they unlock the financial [resources]."

How do you get the pills to kids in need?

In addition to figuring out who will pay for the pills, there's another hurdle: How to get them to preschoolers.

For school-age children, delivering the treatment is relatively easy. The pills are often given en masse to all students regardless of whether they have the parasite. That's because testing for the parasite is not easy and side effects of the treatment are mild.

"You go to the schools, you make the kids all line up and you give them the drug for free," explains Francisca Mutapi, a professor of global health infection and immunity at the University of Edinburgh, who has helped drive the development of pediatric praziquantel. The students are given a cup of water and a pill to swallow.

But in many parts of rural Africa, preschool-aged kids do not attend daycare or nursery school. "So where are you going to find them?" asks Mutapi.

She's reached out to officials to see about integrating a pediatric schistosomiasis treatment into routine vaccination days.

"Some of the countries in Africa have said, 'We're sorry, you cannot use our [vaccination] program because it's crowded already. We've got vitamin supplementation. We've got all the vaccinations. Our health system can't handle that. You need to find another way,' " she says.

Mutapi and The Pediatric Praziquantel Consortium are working on studies in several African countries to determine the best way to reach these children.

Chikwanha's best guess is that a full-scale rollout is still several years away. "The finish line for product development: We're there," he says. "But then the actual work starts which is delivering the product to the children." [Copyright 2024 NPR]