Although regulators may have just allowed a generic version of its asthma drug Pulmicort to be sold in the USA, AstraZeneca is not going to give up its market share without a fight.

Hours after it was revealed that the US Food and Drug Administration has approved Teva Pharmaceutical Industries’ copycat version of Pulmicort Respules (budesonide inhalation suspension), AstraZeneca announced it has entered into an agreement with Par Pharmaceutical which would see the latter firm distribute an authorised generic version of the treatment.

However things are moving quickly in the case and this morning, the Anglo-Swedish drugmaker revealed it has been granted a temporary restraining order in a New Jersey court which stops Teva from launching generic Pulmicort ‘at-risk’. The ban remains in force until further order of the court and a preliminary injunction hearing is scheduled to begin on November 25. The full patent infringement case between the firms is due to commence on January 12.

As part of the New Jersey ruling, Par will suspend distribution of AstraZeneca’s own generic, having already started shipping product yesterday.

AstraZeneca said that despite the launch of generic competition to Pulmicort Respules, the company remains on track to achieve its full-year targets. However earnings per share would be near the bottom of a $4.90-$5.05 range given at the time the firm’s third-quarter results were published.

Before the restraining order was announced, AstraZeneca had said this guidance assumed that core EPS will be negatively impacted by $0.16 per share as a result of lost sales contribution, one-time charges associated with stock write-offs and provisions against inventory in the pipeline. It also reflected “an immediate impairment” of Pulmicort-related intangible assets recognised in March this year under the terms of its joint venture restructuring with Merck & Co.

There is a lot of cash at stake in this patent battle as US sales of Pulmicort last year totalled $964 million, and about 90% of this figure was accounted for by Pulmicort Respules. The latter is indicated for use in children aged 12 months to eight years.

Teva’s decision to launch its copycat version comes with considerable risk as it would have to pay hefty damages if it loses the aforementioned court case.