GOSHI, Kumamoto Prefecture--A national leprosy sanitarium here has found that drug trials conducted on residents during and after World War II violated their human rights and led to the deaths of several patients.

Kikuchi-Keifuen sanitarium released an investigative report about these drug trials on June 24.

The report stated that the facility repeatedly tested the experimental drug “Koha” on at least 472 residents, including children as young as 6.

The doctors did not discontinue the treatments even after severe side effects and deaths occurred. However, the patients had little ability to refuse the treatments, since they were not allowed to live outside the sanatorium.

The report concluded that the residents’ human rights were not respected and questioned the medical ethics of the doctors involved.

Shinzo Izumi, a doctor who has worked at a leprosy sanitarium, said that what happened to the residents “was not a clinical trial for the purpose of evaluating the effectiveness or safety of a new drug. It was a serious violation of human rights.”

Koha, which is composed of cryptocyanin, a photosensitive dye, caught the attention of the former Imperial Japanese Army, which hoped it could be used in cold-weather operations to treat frostbite and burns.

The army commissioned Kumamoto Medical University, today’s School of Medicine at Kumamoto University, to conduct research into the drug’s potential applications.

Since Koha had shown promise in treating tuberculosis patients, it was hoped that the drug might also be effective against the bacteria that causes leprosy.

Matsuki Miyazaki, then director of the Kikuchi-Keifuen sanitarium, joined the research, and began clinical trials on the residents under his care in December 1942.

According to the report, experiments at Kikuchi-Keifuen were conducted on a large scale, initially involving one-third of the sanatorium’s residents.

The doctors tried various methods of administering the medication. Sometimes the drugs were given in powder or pill form. In other cases, they were injected into the patient’s muscles, catheterized directly into the bladder or applied to the conjunctiva of the eye.

Single doses varied from 0.1 milligrams to 120 mg. Dosing intervals also varied from once a day to once a week.

Residents complained of side effects such as fatigue, paresthesia, rashes and nausea.

Nine people died during the trials. The report concluded that two of the deaths were suspected to have been caused by the drug.

One was a 37-year-old man who received Koha injections into his muscle tissue. He complained of dizziness and other symptoms on the 18th day of treatment.

His headaches worsened and he occasionally vomited. Although he stopped receiving the injections, he died 34 days after the start of the treatment.

Another was a 29-year-old man who received injections into his veins. After four and a half months of receiving the medication, his treatment was stopped due to his complaints of general lethargy. He died about two weeks later.

The report concluded that there was “a lack of pathological and pharmacological evidence” to justify these experiments.

The report cited a sanitarium’s journal, in which a 97-year-old male resident recalled his own experience.

“I had a stomach cramp about a month after I started receiving the drug,” the man recalled. “I was rolling about in agony, and my stomach hurt so much that I could not drink tea or water.”

He recalled he was summoned to the director’s office every day to take three pills at a time, as Miyazaki looked on.

The man said, “It was difficult for residents to speak up to the director back then.”

The report noted that the residents at that time could not live outside the sanitarium and were cut off from the outside world. This left them with no choice but to obey the doctors, who were in charge of the sanitarium’s management and operation.

The report found that residents were therefore reluctant to tell doctors that they did not want to participate in the trials, and they could not give honest feedback about the effects of the drug.

When residents’ health deteriorated, the sanitarium did not provide sufficient explanation as to whether Koha was the cause, and the residents did not receive proper treatment or compensation for side effects, the report said.

Residents began to resist clinical trials in 1943.

The report said, “It is natural to assume that many residents had strong suspicions about the drug.”

However, the experiment continued until 1947.

Although the existence of these experiments has been known for a long time, the issue came to renewed attention in 2022 as the Kikuchi-Keifuen historical archives began sorting through related materials.

The current residents’ association then requested a detailed investigation, which led to this report.

The report noted that the purpose of investigating these events is not to hold those involved in the research legally liable, but rather to learn from history to improve the present.

Kazumasa Harada, curator of the sanitarium’s historical archives, said, “We want to examine whether the clinical trials were the correct procedures from the perspective of modern values.”

Akira Ota, 80, vice chair of the sanitarium’s residents’ association, commented on the decision to continue the drug testing without any confirmed efficacy.

“It was a military-led study during wartime, and in addition to that, I think there was a national policy of segregation and discrimination (against patients with leprosy),” Ota explained.

Ota said the association will demand that the sanitarium continue to investigate further, such as checking the medical records and death certificates of the subjects.

“I hope that the records and results of the investigation will be made public and passed on to future generations so that such a thing will never happen again,” he said.

(This article was compiled from reports written by Satoko Onuki, Kei Yoshida and Shohei Okada.)