The Short Story of a Wonder Drug

In 2015 one-half of the Nobel Prize in Physiology or Medicine was awarded jointly to Satoshi Omura of Kitasato University, Japan, and William Campbell, who worked for the Merck Pharmaceutical Co. in New Jersey. This is the story of their discovery.

Omura isolated an unusual Streptomyces bacteria in 1970 from the soil near a golf course along the southeast coast of Honshu, Japan.Omura sent the bacteria to William Campbell, who showed that the bacterial culture could cure mice infected with roundworm. The complex of substances the bacteria released to kill roundworms was named avermectin (“a” in Latin means without and “vermis” means worms). Campbell finally isolated the most potent substance in the avermectin and modified it so it retained its potency and could be given orally. He called the new substance ivermectin.

Ivermectin was marketed in 1981 by Merck as a veterinarian antiparasitic. By 1986 it was registered in 46 countries and used extensively to treat sheep, cattle, and other animals, and by the late 1980’s it was the bestselling veterinarian medication in the world.

Another Merck scientist, Mohammed Aziz, collaborated with the World Health Organization (WHO) to test ivermectin in humans against diseases caused by worms, such as river blindness and lymphatic filariasis (elephant legs). The tests were successful, and in 1987 ivermectin was registered in France to be used in humans, then soon after in other countries under the brand name Mectizan.

All of these diseases caused by parasites are devastating and affect millions in under-developed countries. Merck decided to donate ivermectin to the countries that needed it., and because of the generosity of the Merck Co. river blindness will hopefully be eradicated someday.

Ivermectin has earned the title as a “wonder drug” because of its effectiveness against worm-like parasites and of its safety profile as a medication in humans. To treat river blindness, a single dose of 150mcg per kilogram of body weight will clear the worms from the system for several months. In the treatment of elephant legs, ivermectin is administered along with another drug, albendazole (a drug donated by GlaxoSmithKline) given as a single dose once a year. The research still continues on the ivermectin family of drugs as they are used against scabies, lice and heartworms.

This little-known story is a fascinating example of serendipity, critical thinking, and the generosity of the pharmaceutical industry.

Stay informed and stay healthy.