NOVATO -- Raptor Pharmaceuticals (Nasdaq: RPTP) on Thursday announced a narrowing operating loss in the first quarter, following domestic launch of the company's rare-disease treatment and ongoing expansion to patients in Germany.

The Novato-based company had a net loss of $14.9 million for the first three months of 2014 -- equivalent to 24 cents per share -- compared to a net loss of $15.9 million during the same quarter last year.

Product sale revenue for the company's PROCYSBI treatment was $12.1 million for the quarter, up 20 percent from the prior quarter.  PROCYSBI, designed to treat nephropathic cystinosis, was approved for use in the United States in June of 2013.

Quarterly operating expenses of $21.6 million have grown 32.8 percent over the 12-month period, driven largely by expansion of the company's sales and administrative team. Research and development costs increased 13.5 percent.

Raptor maintained guidance of $55 to $65 million in net product sales for 2014, and noted that current cash and cash equivalents are anticipated to be sufficient to fund operations through the first half of 2015.

Shares in Raptor were trading at $7.57 when the markets closed on Thursday, down 1.17 percent from opening.