The Wall Street Journal is reporting that prosecutors in the USA are seeking some $1 billion from Johnson & Johnson to settle alleged claims of illegal marketing of the firm's antipsychotic blockbuster Risperdal.

The healthcare giant's previous marketing practices for Risperdal (risperidone) have been under investigation since 2004. Specifically the company was accused of claiming that the drug was safer than other antipsychotics, such as AstraZeneca's Seroquel (quetiapine) and Eli Lilly's Zyprexa (olanzapine) and of minimising the risk of diabetes associated with the treatment.

In a filing to the US Securities and Exchange Commission earlier this week, J&J noted that it had set aside an unspecified sum to settle potential civil and criminal charges. The company has since said that discussions with the US government “are ongoing and it is inappropriate to speculate”.

However, the WSJ quotes a person familiar with the situation as saying that prosecutors have been citing as a benchmark a $1.4 billion settlement that Lilly reached in 2009 to resolve a probe into its marketing of Zyprexa.