The market for hepatitis B treatments is still relatively immature but the potential is enormous, with room for a host of new products, according to a new report from Datamonitor.

Despite some two billion people being exposed to the virus and 400 million thought to be chronically infected, “there has been limited development of specific antiviral therapies,” the report says, noting that while the first therapy to be approved for chronic hepatitis B infection was interferon alfa, it was the two antivirals, GlaxoSmithKline’s Zeffix (lamivudine) and Gilead’s Hepsera (adefovir dipivoxil) that led to considerable growth in the market.

The majority of drugs undergoing clinical development belong to the nucleoside or nucleotide reverse transcriptase inhibitor class, notes analyst Brigitte de Lima, who says that the hepatitis B market is expected to be worth $1billion dollars by 2010. However, she warns that despite advances in therapy, unmet needs abound.

Bristol-Myers Squibb’s Baraclude (entecavir) and Roche’s Pegasys (peginterferon alfa-2a) have gained US approval this year [[30/03/05b]], [[16/05/05c]], but “both of these drugs offer incremental therapeutic improvements rather than revolutionary changes,” Ms de Lima says. Datamonitor believes it is unlikely Pegasys will capture market share from antivirals, but believes “there is scope for additional sales either as part of combination therapy with an antiviral or as successive therapy.”

Similarly, Baraclude “does not offer a paradigm change compared to Zeffix or Hepsera, but it does have superior potency and an improved resistance profile.” These factors should mean that Baraclude could gradually establish itself as the antiviral agent of choice for first-line therapy, the report added.

Datamonitor thinks Baraclude sales will peak at $300 million in 2009 in the major markets, a year before the drug’s expected patent expiry. This estimate is considerably lower than other analysts’ estimates, but Ms Lima noted that for hepatitis B products, price is a crucial factor, so uptake of Baraclude will be heavily dependent on the price attained for the drug, particularly in the EU.

The success of Pegasys and Baraclude is expected to be maintained by the potential launches of Novartis’ telbivudine [[02/06/05d]], and Gilead’s clevudine in 2007. However, no further hepatitis B drug launches are expected until 2009-2010 and several drugs will run into generic competition by then, so a downturn in such treatments is expected around 2011.

The report claims that as more companies increase their exposure to the hepatitis B market, there will be more opportunities for combination therapy and Ms Lima concluded by saying “aggressive expansion into under-served regions such as Asia or significant increments in potency, will be vital to ensure continued growth.”