The rise of obesity in the west has also led to a fifth of the population suffering the effects of gastroesophageal reflux disease and while there are new treatments in the offing, knocking AstraZeneca’s Nexium off the top spot will be quite a challenge.

This is the view of Datamonitor which has published a report noting that “the landscape is set to change in the next 10 years as all of the blockbuster proton pump inhibitors will experience patent expiry”, but new market entrants will be required to demonstrate superiority over Nexium (esomeprazole), which is currently “the runaway market leader”.

Datamonitor analyst James Wentworth says that there is evidence to suggest that the obese are more than twice as likely as those with a normal weight to develop reflux symptoms and esophageal erosions. Given that the obesity problem is set to continue “and has recently been branded as a risk comparable to climate change”, the report adds there will be considerably more people suffering from reflux disease.

There are a number of therapies that treat GERD, but PPIs dominate the market and AstraZeneca’s multi-pronged approach to Nexium’s marketing has made it the best-seller, said Dr Wentworth. “It conducted large-scale clinical trials for Nexium, it targeted the drug at thought-leaders, primary care physicians and spent millions on direct-to-consumer advertising,” he adds, noting that while there is not much differentiation between PPIs, “most patients [in the USA] are aware of the healing purple pill slogan for Nexium and that the drug treats heartburn”. They ask their physician for the drug by name, he claims.

However, the success of Nexium “provides a major barrier to entry for new products and subsequently, also to innovation in the market”, claims the report. While generics are arriving to crowd the market further, “there is an unmet medical need for drugs that have a faster onset and longer duration of action as well as drugs for the PPI-unresponsive population”, it notes.

However, “the inclusion of Nexium as a comparator in head-to-head clinical trials is set to become essential to ensure market success and return on investment for pipeline products,” says Dr Wentworth, who highlights two possible competitors, both PPIs. These are Negma’s S-tenatoprazole-Na, “which, at an early stage, shows signs of being better than Nexium” and TAP Pharmaceuticals’ TAK-390MR (dexlansoprazole). In a move that mirrors the strategy that AstraZeneca used for Nexium, which replaced Losec (omeprazole), TAP is expected to launch its drug as the follow-on to Prevacid (lansoprazole). However, Dr Wentworth concludes by saying that the success of dexlansoprazole will be dependent on it can be launched before the patent protecting Prevacid expires in the USA in 2009.