His death was announced by the MD Anderson Cancer Center at the University of Texas in Houston, where Dr. Jordan was a professor. He had renal cancer, his daughter Alexandra Noel said.
Dr. Jordan, who grew up in England and held dual British and U.S. citizenship, once told an interviewer that he had “barely made it out of grade school” with his lackluster grades.
Not reflected on those early report cards, however, was the curiosity, persistence and talent that would make him, in time, one of the most significant cancer researchers of the second half of the 20th century, one known as the “father of tamoxifen.”
When Dr. Jordan began his research in the late 1960s, as a doctoral student at the University of Leeds in England, cancers deemed treatable were attacked in three principal ways: through surgery to remove tumors and through radiation and chemotherapy to kill cancer cells.
Breast cancer patients had historically been subjected to radical, often disfiguring operations to remove the breast and surrounding tissue.
Radiation opened new pathways for treatment but came with serious side effects. Chemotherapy, the latest development in oncological care, represented a revolution in medical science but was often brutal on the patient.
“There was an obsession with the idea [that] combination chemotherapies were going to cure all cancers,” Dr. Jordan told the website Oncology Central in 2019.
“It felt like we were trying to swim upstream,” he added, when he and his colleagues tried to push scientists to look beyond chemotherapy regimens, which mounted relatively indiscriminate attacks within the body, and to consider the possibilities of drugs targeted to specific cancer cells.
Dr. Jordan demonstrated the potential of his idea in an unexpected way, on the anti-estrogen drug tamoxifen that began its pharmaceutical life as an experimental contraceptive.
As a contraceptive, tamoxifen worked beautifully in rats. In women, it was a spectacular failure and “almost guaranteed,” Dr. Jordan told the Chicago Tribune in 1998, “that the woman who took it would conceive a child.”
“During the sexual revolution of the 1960s, the last thing you needed was everybody getting pregnant,” he said.
However, Dr. Jordan saw another use for tamoxifen and undertook further study. For years, it was understood that patients with some forms of breast cancer — those with estrogen receptors — responded favorably to the removal of their ovaries, which produce estrogen.
An anti-estrogen drug, Dr. Jordan surmised, might have a similar positive effect. In 1973, he demonstrated that tamoxifen could prevent mammary cancer in rats.
By the next year, human testing was underway in the United States. In 1977, the Food and Drug Administration approved tamoxifen for use in advanced cases of breast cancer.
The following decade, it was approved for treatment of earlier-stage cancer in conjunction with surgery. And in 1998, the FDA approved tamoxifen for use in high-risk but still healthy patients to prevent the onset of the disease.
After Dr. Jordan’s death, the Prevent Cancer Foundation credited him with discovering “the first FDA-approved drug to prevent cancer.”
Tamoxifen carries risks, including, in some cases, the development of uterine cancer or blood clots. But it remains one of the most prescribed drugs in cancer treatment and ranks on the World Health Organization’s list of essential medicines.
Tamoxifen is what is known as a selective estrogen receptor modulator (SERM). Other SERMs include raloxifene, another subject of Dr. Jordan’s work, which is used for the prevention of osteoporosis as well as breast cancer.
Dr. Jordan was born Virgil Craig Johnson in New Braunfels, Tex., on July 25, 1947. His mother, who was British, and his biological father, who was from Dallas, met while his father was serving in the U.S. military in England during World War II.
The couple had moved to Texas after the war but divorced when Craig, as Dr. Jordan was always known, was a toddler. He and his mother moved to England, where he grew up in Bramhall, near Manchester. He was raised by his mother and his stepfather, who adopted him, and who gave him the surname Jordan.
Despite his poor academic performance, Dr. Jordan developed an early love for chemistry.
“I converted my bedroom into a chemistry laboratory, but it was a real chemistry laboratory, not one of those kid’s kits, with the things I’d gotten from the pharmacy and liberated from school,” he recalled years later.
“There were multiple life-threatening moments when my experiments exploded or caught fire, and I had to throw things out the window,” he continued. “But my mother would always say, ‘at least we know where he is.’”
He ultimately enrolled at the University of Leeds, where he received a bachelor’s degree in 1969 and a PhD in 1973, both in pharmacology, writing his doctoral dissertation on tamoxifen. The university awarded him a doctor of science degree in 1985.
At the University of Leeds, Dr. Jordan joined the Officers’ Training Corps of the British army. He later served in the Intelligence Corps and the Special Air Service and remained for years in the reserve.
In his scientific career, he worked at institutions including the University of Wisconsin at Madison, Northwestern University in Evanston, Ill., Fox Chase Cancer Center in Philadelphia and the Lombardi Comprehensive Cancer Center at Georgetown University Hospital before joining the MD Anderson Cancer Center in 2014.
Dr. Jordan’s marriages to Marion Williams, Monica Morrow and Julia Jauch ended in divorce. Survivors include two daughters from his first marriage, Alexandra Noel of Stillwater, Minn., and Helen Turner of Salt Lake City, and five grandchildren.
As he became known as the “father” of a lifesaving breast cancer drug, Dr. Jordan regularly encountered people, he told the Houston Chronicle, who said to him, “My mother is on tamoxifen, my wife is on tamoxifen.”
“Mothers have seen their children grow up,” he said. “Grandmothers have seen their grandchildren grow up.”