Swiss drug major Novartis has been granted US approval for Tyzeka (telbivudine), an orally-active drug for hepatitis B that has been billed as being more effective than the current standard treatment.

The approval by the Food and Drug Administration (FDA) is for patients with chronic hepatitis B, which infects around 70,000 people in the UA in a typical year. Around 5,000 patients die of the complications of the infection – liver cirrhosis, liver cancer and hepatic failure – as a result.

Telbivudine, which was approved in Switzerland last month as Sebivo, has been tipped as a fairly big seller for Novartis, as clinical trials have suggested it is more effective than the current standard treatment, GlaxoSmithKline's Epivir-HBV/Zeffix (lamivudine), in tackling chronic hepatitis B infections. Analysts have suggested Novartis' drug could achieve annual sales of around $400 million or more at peak.

But a statement issued by the FDA was more guarded in its assessment, noting that the pivotal trial of telbivudine in hepatitis B “produced evidence of antiviral effectiveness, including the suppression of hepatitis B virus, and improvement in liver inflammation comparable to Epivir-HBV, one of five other medications approved to treat patients with chronic HBV.”

Dr Steven Galson, director of the FDA’s Center for Drug Evaluation and Research, said: "Tyzeka offers prescribers another option for treating these patients."

Telbivudine was originally developed by US company Idenix, and Novartis licensed rights to the product in 2003 in a $225 million deal. This is the first product approval for Idenix. Novartis is also working with the US company on another hepatitis B product candidate, valtorcitabine, which is in Phase II testing.

The two companies extended their agreement earlier this year to extend the license to valtorcitabine to include the treatment of chronic hepatitis C, and are also co-developing another oral drug valopicitabine, for this indication.

Meanwhile, two other oral antivirals - Bristol-Myers Squibb's Baraclude (entacavir) and Gilead's clevudine – are coming through development. Roche is also investigating the use of its Pegasys (peginterferon alfa-2a) drug in HBV, although this injectable drug is unlikely to topple the orally active nucleoside analogues as the first-choice treatment for the infection.