S Korean companies Hanmi and Amneal Pharm launch first copy of AstraZeneca's Nexium in US

The first copy of AstraZeneca's big-selling gastrointestinal treatment Nexium has been launched in the US by South Korean companies Hanmi and Amneal Pharmaceuticals.

Hanmi's product, however is not a direct generic of Nexium, which has esomeprazole sodium as its active ingredient. Rather, the esomeprazole strontium product had been granted approval in the US via a route known as 505(b)2, which relied partly on data from existing drugs and therefore required a much smaller clinical dossier.

Though AstraZeneca had initially successfully blocked the product launch, at the end of September an appeals court lifted an injunction first imposed in 2012. The companies are still locked in a a patent infringement case, with a verdict awaited early next year. 

According to PMLive which quoted analysts at Panmure Gordon, it was not directly equivalent (ie an AB rated generic) to Nexium - esomeprazole strontium and was not likely to  make big inroads into the brand, which was AZ's second biggest product.

In a note to clients yesterday, analyst, Savvas Neophytou wrote, "It is unclear what sort of quantities Hanmi has risk appetite for so this may be a storm in a tea cup."

"In a worst case scenario, this week's launch may also trigger other generics entering the market," said Neophytou. He pointed out that  while the first copy of a drug launched at-risk onto the market faced the possibility of triple damages if 'wilful' brand damage could be claimed, the risk scaled down for subsequent entrants.