Masamitsu Yamamoto, a man with advanced liver cancer who fought for medical use of marijuana while on trial for drug possession, died of liver failure on Monday. He was 58.

The former chef from Kanagawa Prefecture had crusaded for the government to permit medical use of marijuana, which is banned by the Cannabis Control Law. He was arrested in December on suspicion of marijuana possession and was standing trial at the Tokyo District Court.

During a court hearing on July 12, when he appeared in a wheelchair, he claimed he used cannabis as a medicine of last resort after exhausting all other medical options and failing in his attempts to get access to legal cannabis treatment.