Nobel Prize in medicine awarded to researchers who discovered drugs for river blindness and malaria

The 2015 Nobel Prize in Physiology or Medicine has been awarded to researchers who “have developed therapies that have revolutionized the treatment of some of the most devastating parasitic diseases,” declared the Nobel Assembly at Karolinska Institutet in a statement on October 5, 2015.

The Nobel Assembly is awarding one half of the prize jointly to William C. Campbell, PhD, and Satoshi Omura, PhD, for their discoveries that led to a novel therapy against infections caused by roundworm parasites. In separate investigations, they developed avermectin, the derivatives of which have radically lowered the incidence of river blindness and lymphatic filariasis, and also show efficacy against an expanding number of other parasitic diseases.

The other half of the prize goes to Youyou Tu for her discovery of artemisinin, a novel drug that has significantly reduced the mortality rates for patients suffering from malaria.

From soil samples to ivermectin

Drs. Campbell and Omura collaborated but worked independently on the development of avermectin. Dr. Omura, of Japan, isolated new strains of Streptomyces from soil samples and successfully cultured them in the laboratory. From many thousand different cultures, he selected about 50 that seemed to hold the most promise against harmful microorganisms.

Dr. Campbell, of the United States, tested Dr. Omura's Streptomyces cultures and showed that a component from one of the cultures was remarkably efficient against parasites in domestic and farm animals. The bioactive agent was purified and named avermectin, which was subsequently chemically modified to the more effective compound ivermectin.

From Chinese herbs to artemisinin

In the late 1960s, as malaria was on the rise, Chinese pharmacologist Youyou Tu, who does not have a PhD or a medical degree, turned to traditional medicine to develop a novel therapy. From a large-scale screen of herbal remedies in malaria-infected animals, an extract from the plant Artemisia annua emerged as an interesting candidate. However, the results were inconsistent, so Tu revisited the ancient literature and discovered clues to successfully extract the active component from Artemisia annua. Tu was the first to show that this component, later called artemisinin, was highly effective against the malaria parasite, both in infected animals and in humans.

The Nobel Assembly stated, “The discoveries of avermectin and artemisinin have revolutionized therapy for patients suffering from devastating parasitic diseases. Campbell, Omura, and Tu have transformed the treatment of parasitic diseases. The global impact of their discoveries and the resulting benefit to mankind are immeasurable.”