Shares in Hikma Pharmaceuticals fell by as much as 7.5 per cent in early trading today after the company cut revenue forecasts for the full year.
Hikma announced this morning that it expects group revenue to fall in the range of of $2bn (£1.5bn) to $2.1bn on a constant currency basis, a reduction from its earlier forecast of $2.2bn.
The company said the updated guidance "reflects changes in the outlook for our generics business, where we have revised our expectation for the launch timing of our generic version of (asthma drug) Advair Diskus and where we are experiencing increased price erosion on our marketed products".
Earlier this month Hikma's version of GlaxoSmithKline's asthma drug was rejected by the US Food and Drug Administration (FDA) due to "major" issues with the application. Shares in Hikma plunged by almost nine per cent at the time.
Today, Hikma said: "We are in the process of reviewing the response and will provide an update on our application as soon as practicable once we have completed this review and discussed it with the FDA."
The FTSE 100-listed pharma firm said it now expects revenue from its generics business to come in around $670m in 2017, versus the previously anticipated $800m.
"This assumes we do not launch our generic version of Advair Diskus in 2017 and reflects the intensifying competitive environment in the US," the group said.
"Through our focus on portfolio optimisation and continued cost savings, we expect to achieve a slight improvement in the profitability of the generics business in 2017 after incurring additional operational costs related to our generic version of Advair Diskus."
This is not the first time the generics market has proven problematic for Hikma: last year the company was forced to cut its full-year sales guidance for the US generics business by £55m.