Transplants and Antivirals

Gertrude Elion, 1918 – 1999

As Elion modified 6-MP, other researchers discovered that the drug suppressed the immune response in rabbits. Scientists had already experimented with organ transplantation, but the body's natural rejection of foreign substances had prevented success in all but identical twins, who have the same genetic structure.

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In 1958, a young British surgeon used 6-MP to prevent temporarily the rejection of a transplanted kidney in a dog. Excited, Elion gave him several similar compounds, in the hopes that one would be even more effective. The following year, he used Elion's drug azathioprine (known as Imuran), to transplant a kidney successfully into a dog named Lollipop. In 1961, doctors used Imuran to perform the first successful kidney transplant between two unrelated humans. Thanks to Elion's work, organ transplantation has become routine today.

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In 1968, Elion returned to an area she had first studied in the 1940s: antiviral medications. Scientists had long believed that any drug able to harm the DNA of a virus would be toxic to the surrounding healthy cells, too. Indeed, one of Elion's early compounds had shown some effectiveness against viruses but was so highly toxic that Elion put it aside in favor of her work on leukemia, transplantation, and gout. But when she heard that a similar compound had shown some antiviral properties, she returned to the subject.

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After several years of work, the Burroughs Wellcome team triumphantly unveiled acyclovir (Zovirax), the first medication effective against viruses. Elion later referred to acyclovir as her "final jewel.... That such a thing was possible wasn't even imagined up until then." In 1984, the year after Elion retired, her lab developed AZT, the only drug licensed to treat AIDS in the United States until 1991. Although Elion claimed to have had little to do with AZT, her methodology had laid the groundwork for its discovery.