VESTAR'S AMBISOME LAUNCHED IN THE UK

The first liposomal formulation of a drug has now been launched in the UK, in the form of Vestar's Ambisome, a liposome-encapsulated amphotericin B antifungal. The new product is licensed for the treatment of severe systemic or deep mycoses, particularly in immunosuppressed patients such as those with AIDs or patients undergoing cancer chemotherapy. The drug is of particular use in the treatment of infections like aspergillosis, which does not respond well to existing antifungal therapy and can be fatal in susceptible patients.

Vestar says that Ambisome is at least as effective as conventional formulations of amphotericin, such as Bristol-Myers Squibb's Fungizone/Fungilin, although it claims it is much safer. Amphotericin is a highly toxic drug and side effects are common, requiring close supervision of patients receiving it. Reactions commonly observed include nausea and vomiting, febrile reactions, muscle and joint pain and headache, and it can also produce dose-related nephro- and cardiotoxicity.

Encapsulating the drug in a liposomal complex not only reduces the toxicity, it also acts as a form of drug targeting. The liposome particles are thought to be recognized as foreign and ingested by polymorphonuclear phagocytes. As the cells migrate towards sites of infection they take the drug with them and increase the concentration of amphotericin in infected tissues.