Challenge #2: Complete Cure
Inventing a Wonder Drug to Win the Malaria Fight
The story of malaria control is the story of the promise – and peril – of wonder drugs. With hundreds of millions of people infected with malaria around the globe every year, effective treatment may be the difference between ending the disease and humanitarian disaster.
Quinine, the first antimalarial, was discovered in the bark of the cinchona tree in the foothills of the Andes Mountains back in the 1600s. But it was hard to produce and administer, and there still was no reliable global supply by World War I.
Finding a cheap, reliable alternative to quinine that could be mass-produced became a military imperative during World War II. America suffered humiliating defeats “not because the ammunition was gone,” The New York Times reported, “but because the quinine tablets gave out.”
However, the synthetic drugs that emerged from that furious R&D effort – most notably chloroquine – were little match for the fast-evolving parasite, which developed resistance in under a decade.
Our current front-line treatments for malaria, called artemisinin-based combination therapies (or ACTs for short), underscore the arms race between science and parasite. ACTs have been wildly successful in saving lives – a true wonder drug by any definition – but their effectiveness may also be cut short by resistance.
First touted for its curative powers in an ancient Chinese medical book dating back to 168 BC, artemisinin was finally brought to scale globally by Swiss healthcare company Novartis, which received WHO international approval for its drug in 1999. Global funders threw their weight behind ACTs five years later, and today more than 280 million ACT treatments are distributed every year in Africa alone.
But resistance is once again threatening to rob us of our best tool in the malaria fight. Just as chloroquine resistance emerged along the Thai-Cambodia border back in the 1960s, first signs of artemisinin resistance have now been documented in the region. If it follows the same pattern as past resistance – emerging across Asia, in India, making the leap to Africa – it could potentially cost millions of lives.
History has shown that containment isn’t an option: Only by eliminating malaria in Asia-Pacific can we staunch the spread of resistance. So the Greater Mekong subregion will be ground zero for a renewed global eradication effort.
In Search of a Solution
The race is already on to develop the next generation of wonder drugs—this time tailor-made for eradication. Such a drug would have four key features.
First, it would be a single-dose treatment. The pharma industry talks about the “pill burden” – the total number of pills someone has to take to complete a full course of treatment. The more pills, over more days, the greater the chance that a patient will stop midway and fail to be fully cured.
Malaria treatment currently requires between three and 14 days of treatment, depending on the strain of the parasite. Getting people to take all their pills is complicated by the fact that the drugs are so fast-acting and effective that malaria symptoms may subside after the first or second day, leading people to think they’ve been treated, when in fact trace amounts of the parasite may still be hanging around in their bodies waiting to mount another attack. A single dose treatment would ensure that everyone who is treated is parasite-free.
The second feature of a new wonder drug is that it will be a “complete cure.” Malaria is so challenging in part because the parasite plays hide and seek in the human body: traveling in the bloodstream, lodging in the liver, the brain – even bone marrow, as a recent study highlighted.
Before you can hope to eliminate malaria in a community of people, you must be able to effectively eliminate it in a single person. A complete cure treatment would wipe out the parasite at every stage of its lifecycle, ensuring zero risk of passing the parasite along to others.
The third feature is what we call a prophylactic effect. Essentially, you want a drug that will remain in the body for a period of time to prevent a person from developing another case of malaria if bitten again by an infected mosquito.
And finally, the new treatment would have a high barrier to resistance, so even as you scale up use it’s able to maintain its effectiveness. This means developing an arsenal of molecules that attack the parasite in novel ways, and then using drugs in combination to stave off resistance. New malaria drugs are a great investment, but they’re expensive to develop, so we must ensure they last.
In the Pipeline
The good news is we’re well on our way to making a new slate of wonder drugs (or “one-der” drugs) a reality. Supported by a product development partnership called Medicines for Malaria Venture out of Geneva, the malaria community and pharma industry leaders including Novartis, Sanofi, and GlaxoSmithKline have started clinical trials for treatments that will make ending malaria a reality.
As one example, Novartis has fast-tracked its first non-artemisinin based single-dose drug candidate, called KAE609, and recently published results showing that it was able to clear malaria parasites in adults in 12 hours on average. Read more about the quest for a malaria wonder drug here.