(Sharecast News) - Circassia Pharmaceuticals announced on Monday that the US Food and Drug administration had approved its latest treatment for obstructive pulmonary disease called Duaklir.Duaklir is a fixed-dose combination of the long-acting muscarinic antagonist (LAMA) aclidinium bromide (400 mcg) and long-acting beta-agonist (LABA) formoterol fumarate (12 mcg) that is administered twice-daily via the breath-actuated inhaler Pressair.The new treatment was scheduled for launch in the US in the second half of 2019 via its dedicated COPD sales force.Steve Harris, Circassia's CEO, said: "We are delighted with the FDA approval of Duaklir, which we believe will provide a valuable treatment option for the significant number of patients with COPD in the United States."The addition of Duaklir to our portfolio further strengthens our range of marketed respiratory products and we look forward to launching it in the US in the coming months alongside our aclidinium monotherapy, Tudorza, as part of the significant LAMA / LABA market that is predicted to grow rapidly over the coming years."In 2017, Circassia and AstraZeneca established a collaboration for the commercialisation of Tudorza and Duaklir in the United States. At the end of 2018, Circassia exercised its option over Tudorza and the Company now has the full US commercial rights to both products.Under the two companies' agreement, a contingent option fee of $20m becomes due to AstraZeneca within 30 days of the FDA approval of Duaklir, and final deferred consideration of $100m is due by 30 June 2019.As of 1516 BST, shares of Circassia were 18.93% higher at 33.30p.