Antiviral drug research
Flu viruses are unpredictable. It is impossible to say whether the virus that causes the next pandemic will be treatable with the antiviral drugs that are currently available. We will only be able to tell once the virus emerges, and we study it: will current drugs work? For how long? Will the virus remain sensitive to the drugs, or will it develop resistance? How quickly?
These questions have prompted many nations to make antiviral drugs a research priority. Ongoing research into the best use of existing medications is being performed by a number of groups. In addition, there are some promising new drugs under development. However, new medications are years away from commercial production.
Potential New Antivirals
Peramivir is a new neuraminidase inhibitor being developed as an injectable drug. It shows activity against influenza A and B, including A/H5N1. Phase 2 clinical trials began in 2007. In October 2008, two Phase 2 trials were completed (see press releases here and here). During the H1N1 flu pandemic, the US allowed the drug to be used under certain circumstances. Several other countries began granting it limited licenses in early 2010.
Fludase® is a new type of drug which blocks all strains of influenza viruses entering cells, including A/H5N1. It is designed as an oral inhalant, and is currently under clinical development.
Second generation zanamivir (CS-8958) is being developed by Biota, the Australian company that developed the original zanamivir. It is a long-acting neuraminidase inhibitor (LANI), inhaled once a week. In 2008, results from Phase II clinical trials showed this drug was just as effective as oseltamivir (Tamiflu®) when used against H5N1 bird flu, influenza A and influenza B.