U.S. Patent 2,893,839 for 2-amino-6-mercaptopurine was issued to Elion and Hitchings.
On June 23, 1959, Gertrude B. Elion and George H. Hitchings were awarded U.S. Patent 2,893,839 for 2-amino-6-mercaptopurine, marketed as Purinethol. This drug was a breakthrough in the field of chemotherapy, specifically targeting leukemia cells. It represented a paradigm shift towards rational drug design, contrasting with the empirical methods that dominated the era. The invention has been pivotal in treating childhood leukemia, significantly increasing survival rates. Purinethol became a cornerstone in chemotherapy regimens, embodying Elion's innovative spirit and commitment to combating cancer.