Intravenous zanamivir

A young woman with severe H1N1 pneumonitis who was previously neutropenic with chemotherapy for Hodgkin’s disease has responded to intravenous zanamivir (Relenza) and methylprednisolone. Her case is reported in the Lancet.1

Although the use of intravenous zanamivir is unlicensed it exists and is being studied as part of a clinical trial2 (with oral Oseltamivir) in humans and others have investigated its use in experimental influenza3. The clinical team had to apply to their hospital formulary, seek consent from relatives and source the treatment directly from GSK. Since the most severe cases of H1N1 pneumonitis are likely to be ventilated it would make sense to gain experience with intravenous antivirals.

The interesting point in this case is the combination of intravenous zanamivir with methylprednisolone in a severe case of H1N1 influenza in a patient with neutropenia. The authors suggest that this warrants further study.

1) Kidd IM, Down J, Nastouli E, Shulman R, Grant PR, Howell DCJ, Singer M. H1N1 pneumonitis treated with intravenous zanamivir. The Lancet, Early Online Publication, 4 September 2009.

2) Pukrittayakamee S. Phase 1, Open-Label Study to Evaluate Potential Pharmacokinetic Interactions Between Orally-Administered Oseltamivir and Intravenous Zanamivir in Healthy Thai Adult Subjects. identifier NCT00921726

3) Beigel J, Bray M. Current and future antiviral therapy of severe seasonal and avian influenza. Antiviral Res. 2008 Apr;78(1):91-102. Epub 2008 Feb 4.