A US court has confirmed that a key patent on AstraZeneca’s Pulmicort Repsules is invalid and Actavis has immediately launched its version of the asthma drug.

The decision by the court in New Jersey also ruled that AstraZeneca's request for a permanent injunction is denied, opening the way for Actavis' copy of Pulmicort Respules (budesonide) as it does not infringe “the ‘834 patent”. The Anglo-Swedish drugmaker had hoped the latter patent would expire in 2018, with paediatric exclusivity extending into 2019.

The news is also a blow for Teva Pharmaceutical Industries which has been earning healthy sums on selling an exclusive, authorised generic version of Pulmicort Respules since the end of 2009.

For the 12 months ended June 30, 2014, total US brand and generic sales of Pulmicort Respules were approximately $1.1 billion, Actavis said. An Abbreviated New Drug Application for its generic received final approval from the US Food and Drug Administration back in August 2012.

Paul Hudson, executive vice president for AstraZeneca in North America, said the firm "strongly disagrees with the court’s decision,” adding that it has "full confidence in the strength of its intellectual property rights protecting Pulmicort Respules". He noted that AstraZeneca is “reviewing the decision and considering our legal options, including an appeal”.

Despite their legal wrangling over Pulmicort Respules, AstraZeneca and Actavis recently agreed a deal which will see the former buy the Switzerland-based group’s branded respiratory drug business in North America for an initial $600 million.

Actavis divests Pharmatech

Meantime Actavis, which is in the process of buying Allergan for $66 billion, is selling its outsourcing and R&D business Aptalis Pharmaceutical Technologies, known as Pharmatech, to private equity firm TPG. No financial terms were disclosed.