Elion's team created acyclovir, a pioneering antiviral

Person: Gertrude Elion
Lived: 1918–1999
Field: Pharmacology
From: American

The story

For much of the twentieth century many scientists doubted that viruses could be treated safely with drugs. Viruses live inside human cells and borrow their machinery, so most compounds that harmed a virus also harmed the patient.

Gertrude Elion and George Hitchings had spent decades exploiting the biochemical differences between normal human cells and harmful ones, from cancer cells to bacteria and malaria parasites. As early as the 1950s they had shown that their purine compounds had to be converted into nucleotides inside a cell before they became active. That insight became the key to a new kind of antiviral drug.

In the 1970s Elion's department at Burroughs Wellcome developed acyclovir together with the chemist Howard Schaeffer, who had co-discovered the compound and then joined the company. Herpes viruses make their own version of an enzyme, thymidine kinase, which is much less selective than the human one. That viral enzyme switches acyclovir on, so the drug becomes active almost only in infected cells and stops the virus from multiplying. Elion and her colleagues described this selectivity in a 1977 paper.

Acyclovir was approved for medical use in 1981 and sold as Zovirax. It proved effective against herpes simplex and against the related virus that causes chickenpox and shingles, and it is also used to prevent some infections after transplants. The Nobel Assembly called it the first effective drug in the treatment of herpes virus infections, and Wikipedia describes it as the first selective and effective drug of its kind.

The discovery was cited when Elion shared the 1988 Nobel Prize in Physiology or Medicine. It showed that viruses, too, could be targeted precisely, and the National Inventors Hall of Fame notes that acyclovir paved the way for AZT, the first drug approved to treat AIDS. Today acyclovir is available as a generic medicine and is on the World Health Organization's List of Essential Medicines.

Why it matters

Acyclovir has eased suffering for millions of people with herpes, chickenpox and shingles, and it proved that drugs could be designed to strike viruses while sparing healthy cells.

About Gertrude Elion

Chemist without a doctorate who pioneered rational drug design and created drugs for leukaemia, transplants, gout and herpes, sharing the 1988 Nobel Prize in Physiology or Medicine.

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Gertrude Elion

1918–1999 · Pharmacology

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