Shares in Hikma Pharmaceuticals (LON:HIK) fell over 10 percent in early trading on Thursday, after issuing a warning that annual revenue was likely to be at the lower end of guidance.

The FTSE 250 pharmaceutical company said annual revenue was likely to be about $100 million lower at $2 billion. It also lowered its guidance for the sales of generic products, blaming it on an “increasingly challenging environment”.

The Jordan-based company, which makes and sells branded and non-branded generic and injectable drugs, said it had also been affected by stiffer competition in the US. Its revenue estimate for the region was cut back to $620 million for the year, down from an initial estimate of $800 million in April.

Shares in Hikma are currently trading down 13.75 percent at 1,141.01 (1045GMT).