The test strain, Bifidobacterium longum (APS001F) which expresses adenosine deaminase (AD), will be administered intravenously followed by 5-fluorocytosine, leading to selective formation of highly toxic 5-fluorouracil in anaerobic environments where tumor tissue is located. The patient is also given maltose, a growth factor for Bifidobacteria. Experiments on mice and rats in Japan led to a strong enrichment of 5-FU in tumor tissue. Eisai Co. has taken an option on this system.

Anaeropharma Science press release, https://www.anaeropharma.co.jp/j/research/