Dublin-based Jazz Pharmaceuticals said revenues rose 15 per cent in the second quarter of the year as sales of its Xyrem product increased.

The company reaffirmed financial guidance for 2015, which puts revenue in the projected range of $1.31 billion to $1.37 billion

Adjusted net income attributable to Jazz Pharmaceuticals rose to $152.2 million, or $2.41 per diluted share, compared to $125.9 million, or $2.02 per diluted share, for the second quarter of 2014.

Operating expenses fell to $180.4 million from $216.9 million in the second quarter of 2014. However, that decrease was due to an intangible asset impairment charge of $32.8 million recorded in the second quarter of 2014, related to the acquisition of EUSA Pharma. The products involved in that impairment charge have since been sold.

"Our second quarter results reflect strong top- and bottom-line growth, strong margins, and continued investment in our commercial and R&D portfolios to support our long-term growth strategy," said chief executive Bruce Cozadd, adding that the company had already made "significant progress" towards its research and development goals for the year.

Net sales of its Xyrem oral solution rose by 30 per cent to $247.8 million in the second quarter of the year, with the average number of active Xyrem patients in the US increased to approximately 12,475. However, net sales of its Erwinaze/Erwinase product fell by more than $1.5 million despite a rise in demand, as increased chargebacks and rebates hit its figures. Other products, such as Defitelio/defibrotide, were impacted by foreign exchange rates, along with the discontinuation of the cost recovery programme in the US in July 2014.

Gross margin for the period was 93.4 per cent.