AI-designed phages: Start-up reports first use in a patient

US start-up Radical Numerics says it is the first in the world to have given a human bacteriophages designed with artificial intelligence. Phages are viruses that infect bacteria but not human cells; they are seen as a possible alternative when antibiotics no longer work because of resistance. According to the company, the patient had a difficult-to-treat, antibiotic-resistant bacterial infection and was treated under a physician-led compassionate-use pathway. The company published a technical report on Oct. 20, 2026.

The phage cocktail was designed with the company's own Omnii-1 language model, trained on genomic data, which modifies selected sections of phage genomes, such as the proteins the viruses use to attach to bacteria. Before administration, the cocktail killed the patient's resistant pathogen in the lab, the company said. According to the Daily Caller, citing The New York Times, company officials said the US Food and Drug Administration (FDA) authorised the use under its single-patient programme; the FDA did not comment on the record.

Key questions remain open: citing privacy, the company has not disclosed the illness, the course or the outcome of the treatment, and the doctors and clinic were not named. The report has not been peer-reviewed. Radical Numerics itself stresses that more research is needed to establish safety and effectiveness and that such therapies are not approved for broader clinical use; chief executive Eric Nguyen told The New York Times the company intends to publish its findings through peer-reviewed research.