In 1948, George Hitchings and Hitchings and laboratory assistant Gertrude Elion synthesized 6-mercaptopurine (6-MP), an antimetabolite, to combat childhood leukemia. In 1988, the Nobel Prize in Physiology or Medicine 1988 was awarded jointly to Sir James W. Black, Gertrude B. Elion and George H. Hitchings “for their discoveries of important principles for drug treatment.”