The Birth of Chemotherapy at Yale: From Wartime Secrecy to Modern Cancer Care

The origins of chemotherapy can be traced to World War I. Physicians treating soldiers exposed to mustard gas observed that the chemical severely damaged bone marrow and lymphatic tissue. White blood cell counts dropped sharply, and lymph nodes shrank.

Those effects were devastating in war—but they suggested a scientific possibility. If mustard compounds destroyed rapidly dividing white blood cells, might a related compound also affect cancers of the lymphatic system?

In the early 1940s, after the United States entered World War II, the federal government launched a classified program to study chemical warfare agents. At Yale School of Medicine, pharmacologists Louis S. Goodman, MD, and Alfred Gilman, PhD, were assigned to investigate sulfur and nitrogen mustards. In laboratory studies, nitrogen mustard caused lymphoma tumors in mice and rabbits to shrink dramatically.

Because the research was classified, the compound was referred to only as “Substance X.” But its potential was becoming clear.

Working with surgeon Gustaf Lindskog, MD, the team identified a patient with advanced lymphosarcoma (a cancer of the lymph nodes) who had exhausted all available treatments. The patient—a 47-year-old factory worker from Meriden, Connecticut known only as “J.D.”—had tumors so extensive he could barely move his head. Radiation had failed. Understanding the risks, he agreed to receive the experimental drug.

On August 27, 1942, J.D. became the first person in the world to receive intravenous chemotherapy.

The response was swift. Within days, J.D.’s tumors softened. He regained mobility and slept more comfortably. Over the following weeks, the tumor masses regressed dramatically. For a time, the cancer was no longer detectable on clinical exam.

For the first time, a drug circulating through the bloodstream had caused widespread regression of a systemic cancer. The implication was profound: cancer could be treated with medicine delivered throughout the body—not only with surgery or radiation directed at a single site.

But the experiment also revealed chemotherapy’s dangers. Nitrogen mustard damaged healthy rapidly dividing cells along with cancer cells. J.D.’s bone marrow—where blood cells are produced—was severely suppressed, causing his white blood cell count to fall and weakening his immune system. Although the tumors initially disappeared, resistant cancer cells survived. The disease returned aggressively, and J.D. died on December 1, 1942.

In a single case, physicians witnessed the defining features of chemotherapy: tumor shrinkage, systemic side effects, and the emergence of drug resistance—patterns that continue to shape oncology today.

Because the research was conducted under wartime secrecy, Goodman and Gilman did not publish their results until 1946 in The Journal of the American Medical Association. During the upheaval of the war years, J.D.’s original hospital record was misplaced.

Decades later, Yale physicians John E. Fenn, MD, and Robert Udelsman, MD, undertook a meticulous archival search and recovered the lost medical file, publishing a corrected account in 2011 in the Journal of the American College of Surgeons. Their work clarified the historical record and reaffirmed Yale’s central role in the birth of chemotherapy.

Nitrogen mustard became the model for a class of drugs known as alkylating agents—chemotherapies that work by damaging the DNA of rapidly dividing cells. Because cancer cells multiply quickly, they are especially vulnerable to this type of injury. Variations of these drugs remain part of cancer treatment today.

Over the following decades, physicians improved chemotherapy by combining multiple drugs, refining dosing, and developing supportive treatments to manage side effects such as low blood counts. Some cancers that were once fatal—including Hodgkin lymphoma—became highly treatable. A new medical specialty, medical oncology, emerged around the concept of systemic cancer therapy.

Cancer treatment has continued to evolve. Today at Yale, researchers analyze the genetic changes that drive individual tumors, allowing therapies to be matched to specific molecular features. Scientists are studying why cancers become resistant to treatment and developing new delivery systems designed to target tumors more precisely while reducing harm to healthy tissue. Chemotherapy is often combined with immunotherapy—treatments that help the immune system recognize and attack cancer—or with targeted drugs that block specific growth signals within cancer cells.

The principle first demonstrated in 1942—that cancer could respond to drugs delivered through the bloodstream—remains foundational. What has changed is the level of precision, safety, and biological understanding behind those treatments.

The first infusion at Yale proved that cancer could be treated chemically. The work underway today seeks to make that chemistry more targeted, more durable, and more humane.