Long-acting ‘multivalent’ flu drugs clump viruses together and beat existing antivirals in mice
Chinese researchers attached two or three copies of the flu drugs zanamivir or peramivir to an antibody fragment. In a Nature Communications study published on 4 October 2026, the trivalent peramivir version outperformed baloxavir and the long-acting candidate CD388 against several flu strains in mice. No human data yet.
A study published in Nature Communications on 4 October 2026 describes a new way to build long-acting influenza drugs. The team was led by researchers at the Academy of Military Medical Sciences in Beijing, together with Xiamen University, Tsinghua University and the University of Hong Kong, among others.
The idea
Existing flu drugs such as zanamivir and peramivir block neuraminidase, the enzyme the virus uses to break free from infected cells. A newer class of medicines links a small-molecule drug to the Fc region of an antibody, which keeps it in the body much longer; one such candidate in development is called CD388. The authors wanted to understand how attaching the drug to Fc changes the way it works.
What they found
- Using a modular “click chemistry” platform, they built antiviral conjugates (AVCs) carrying one, two or three copies of zanamivir on Fc. The three-copy (trivalent) version, AVC-Z3, was the most active.
- AVC-Z3 made flu particles stick to each other in clumps. This blocked the virus both from entering cells and from being released — a physical immobilisation of the virus, not just enzyme blockade.
- A trivalent peramivir version, AVC-P3, was even more potent in lab tests and lasted much longer in the body than AVC-Z3 and a modified form of CD388.
- In mice infected with H1N1, H3N2, H5N1 (bird flu) and influenza B, AVC-P3 worked better than the other conjugates, the approved drug baloxavir and CD388.
Limitations
The results come only from cell experiments and mouse models; there are no human data yet on safety, dosing or effectiveness, and many drugs that work in mice fail in people. The comparisons were run by the developers’ own team. The work was funded by Chinese national research grants, and the authors declare no competing interests. If confirmed in clinical trials, the approach could lead to longer-lasting flu treatment or prevention, but that is years away. For flu protection today, talk to your doctor about vaccination and approved antivirals.
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