AstraZeneca and Circassia are partnering to develop and commercialize two inhaled respiratory treatments for COPD in the US, according to a news announcement.

Tudorza (aclidinium bromide) was approved by the US FDA in 2012, and its marketing began that year. Duaklir (aclidinium bromide) is marketed in the European Union and a number of other countries. It is expected to be submitted for US regulatory review in 2018.

Both Duaklir and Tudorza were formulated as a dry powder for inhalation. They are delivered by a multi-dose dry powder inhaler called the Pressair, marketed in some countries as Genuair.

AstraZeneca will receive an initial $50 million in shares, and $100 million more if the FDA approves Duaklir.