25-06-2025
5 more leprosy facilities found to have tested drug on patients
The drug 'Koha' stored at Kikuchi-Keifuen, a national sanitarium for leprosy patients in Koshi, Kumamoto Prefecture. Blueish-blackish powder can be seen inside the glass containers. The photo was taken on Dec. 8, 2022. (Asahi Shimbun file photo)
Five more national leprosy sanitariums during and after World War II have reported administering an experimental drug called "Koha" to residents that caused severe side effects in some patients.
The disclosures follow the release of an investigative report by the Kikuchi-Keifuen sanatorium located in Koshi, Kumamoto Prefecture, in June 2024, disclosing the practice, which has since prompted investigations at other facilities.
The Asahi Shimbun contacted 12 national sanatoriums, excluding Kikuchi-Keifuen, by June this year.
Based on preserved documents and medical records, the administration of Koha was confirmed at the National Suruga sanatorium in Shizuoka Prefecture; Oshima-Seishoen in Takamatsu; Tama-Zenshoen in Tokyo; Nagashima-Aiseien in Okayama Prefecture; and Hoshizuka-Keiaien in Kagoshima Prefecture.
Koha, composed of cryptocyanin, a photosensitive dye, was developed under the former Imperial Japanese Army. The military was interested in its application for frostbite and burn treatment in cold-weather operations.
The military commissioned the research of Koha to Kumamoto medical university, which is now the School of Medicine at Kumamoto University. After some apparent success in tuberculosis patients, which involved bacteria similar to mycobacterium leprae, the drug was tested on leprosy patients.
The director of Kikuchi-Keifuen was commissioned by the 7th Research Center of the Army Technical Headquarters to conduct a trial administration of Koha.
It was conducted on at least 472 residents of the sanatorium between 1942 and 1947. Nine patients died during the trial period, with two deaths suspected to be directly linked to Koha.
At the Suruga sanatorium, a thorough review of all 998 residents' medical records is under way to determine the drug's use.
Shinichi Kitajima, the sanatorium director, confirmed that the use of Koha was found in post-war medical records. Staff members bound by confidentiality are carefully reviewing the records one by one. He said the task 'will take time to fully uncover the facts.'
'There is a possibility that more unknown facts will come to light. We need to establish rules for preserving medical records and documents,' Kitajima added.
Information regarding the administration of Koha at Tama-Zenshoen and Oshima-Seishoen was found in the 1947 issue of the journal of dermatology and venereology, which is now preserved at the National Hansen's Disease Museum.
According to the journal, the director of Tama-Zenshoen reported that of 175 cases, the use was discontinued in 72 within three months, while 103 continued for four to eight months. The facility needed to stop administrating Koha in 57 cases due to the general deterioration of the resident's health.
The director of Oshima-Seishoen also reported administering Koha to 180 people.
'There were many side effects of the drug. But they diminished after stopping the drug,' he wrote.
The administration of the drug at Oshima-Seishoen ran from 1944 to 1946, which overlapped with the period of operation at Kikuchi-Keifuen.
Records regarding Koha's administration were also found in Nagashima-Aiseien's institutional journal and the residents' association magazine at Hoshizuka-Keiaien.
Other facilities said that the number of records is too large and that they are considering how to proceed with their research.
'Investigations should be conducted at sanatoriums across the country,' said Akira Ota, acting chairperson of the Kikuchi-Keifuen residents' association.
According to the health ministry, as of May this year, there are 639 residents in national sanatoriums, with an average age of 88.8 years old.
SUFFERING FROM SIDE EFFECTS
A doctor at Oshima-Seishoen told Tsuneji Matsumoto, who is now 93, along with other young residents around early 1944, that 'A new drug for leprosy has been developed. You'll take it.'
Records confirm that Koha was administered at this facility.
According to Matsumoto, who entered the facility in July 1942 and still lives there, the drug was given under the pretext of leprosy treatment.
The 'thin, flat tablet' was taken once a day before noon. Afterward, he felt dazed and his vision deteriorated. He remembers crawling along the hallways saying, 'I can't see, I can't see.' Then, he became hospitalized.
He recalls others around him suffering from fevers or festering wounds. One woman lost her hair and cried. Due to these painful side effects, some patients said they didn't want to take the medicine anymore.
However, the doctor said that, 'It's working because you're having a reaction,' and continued administering it.
Some residents pretended to have taken the pill, hiding it under their tongues and spitting it out later.
However, this ruse was eventually discovered. Nurses began checking to ensure that each tablet was swallowed.
Matsumoto recalls the pill treatments lasting from six months to a year. One day, without explanation, the prescription was abruptly halted. He later heard that the military ordered the administrating of Koha.
'I believe that the doctors at the sanatorium weren't able to refuse,' he said. 'The military was terrifying.'
(This article was compiled from reports written by Satoko Onuki, Ryutaro Ito and Kei Yoshida.)
