New Coronavirus: "Possibly Effective Against All Variants"? The Key to Overcoming Mutations Lies in "Humans" — RIKEN and Others Take the Next Step with TMPRSS2 Antibodies

On September 11, 2025, a collaborative research group from RIKEN, the Institute of Medical Science at the University of Tokyo, and Shiga University of Medical Science announced the development of a monoclonal antibody targeting the human enzyme TMPRSS2, which is essential for SARS-CoV-2 infection. This antibody was shown to suppress infection across all examined variants, including Omicron. Notably, the antibody does not inhibit the enzymatic activity of TMPRSS2 itself but physically disrupts the interaction among spike, ACE2, and TMPRSS2. The effectiveness of both prophylactic and therapeutic administration was suggested in human lung organoids, mice, and cynomolgus monkeys. The findings were published in iScience. On social media, there are voices of optimism, calling it "Nobel Prize-worthy," alongside cautious remarks pointing out that safety and efficacy have not yet been verified in preclinical stages. It is crucial to carefully assess the reproducibility in clinical trials, the emergence of alternative entry pathways (endosome/MMP), and implementation challenges such as administration routes and costs.