William C. Campbell, Satoshi Ōmura, and Youyou Tu win for drugs against parasitic diseases
THREE OCTOGENARIANS who developed cures for malaria and roundworm diseases have won this year’s Nobel Prize In Physiology or Medicine. William C. Campbell of Drew University and Satoshi Ōmura of Japan’s Kitasato University will share half the prize for developing avermectin and ivermectin. These drugs cure diseases caused by parasitic roundworms, including river blindness and elephantiasis. “I humbly accept it,” Ōmura said to a member of the Norwegian Nobel Committee. The Japanese scientist confirmed that the avermectin family of natural products emerged from soil samples containing Streptomyces bacteria that he had collected near a golf course. His cowinner, Campbell, who was then working at Merck & Co., led the medicinal chemistry campaign that turned avermectin into ivermectin ( J. Med. Chem. 1980, DOI: 10.1021/jm00184a014 ). The other half of this year’s Nobel Prize in Physiology or Medicine goes to Youyou Tu of the China Academy of Traditional Chinese Medicine for her work to discover artemisinin, a drug against malaria. Artemisinin was developed as part of a secret research initiative called “573,” launched by Mao Tse-tung in 1967 during the height of the Vietnam War. The initiative was launched as many Chinese soldiers fighting for communist North Vietnam were dying of malaria because the existing drug, chloroquine, was no longer effective ( Cell 2011, DOI: 10.1016/j.cell.2011.08.024 ). More than 50 laboratories and 500 scientists were involved in the secret project that eventually led to artemisinin. To find inspiration for the drug, Tu looked in many ancient Chinese medicinal texts and assembled some 2,000 possible recipes that claimed to cure the fever symptoms common in malaria patients. The team found what they were looking for in a manuscript from A.D. 340 called the “Handbook of Prescriptions for Emergencies.” The recipe required the scientists to perform an extraction from a common Chinese plant called sweet wormwood. After carrying out the extraction, they found a chemical that was active against malaria: artemisinin. Its derivatives are still used today to fight malaria. The discovery of artemisinin has had “unbelievable impact,” says Peter Seeberger, a malaria researcher and director at the Max Planck Institute of Colloids & Interfaces. “To say that millions of lives have been saved is an understatement.” Some 350 million doses of artemisinin-derived drugs are given every year, he says. The development of ivermectin was “absolutely revolutionary,” says John Chabala, who worked as a chemist on the drug at Merck under Campbell starting in the 1970s. Before ivermectin was introduced in 1987, millions of acres of agricultural land in Africa lay dormant because inhabitants had evacuated to escape the roundworm parasite causing river blindness. Where locals had stayed, “there were villages where the entire adult population was blind,” Chabala says. Merck officials decided to donate the drug in perpetuity, a charitable act that has helped millions of people, he adds. “Parasitic diseases have plagued humankind throughout our existence. And still today they affect hundreds of millions of the most vulnerable citizens of the world,” says Hans Forssberg, a member of the committee that selected the prize. The global impact of these drugs “is immeasurable,” he adds.