Shares in AstraZeneca have dipped this morning on the news that Teva has gained a US approval for a generic version of its Pulmicort asthma drug and mixed data from a trial of its lung cancer drug Zactima.

The Anglo-Swedish drugmaker said that while the US Food and Drug Administration agreed with some of its concerns about the approval of any generic version of Pulmicort Respules (budesonide inhalation suspension), other arguments in its Citizen Petition were denied. As a result, the FDA has granted approval for a generic version of AstraZeneca's drug but the latter firm says that litigation against the Israeli drugmaker for patent infringement continues, with the court case to commence on January 12.

AstraZeneca said it disagrees with “several elements of the FDA's decision” and is considering its options to respond. The firm added that it has full confidence in the strength of its intellectual property rights protecting Pulmicort Respules, which is indicated for use in children aged 12 months to 8 years, and will continue “to vigorously defend and enforce” its rights. The patents expire in 2018 with paediatric exclusivity extending to 2019.

AstraZeneca also revealed Phase III data on its investigational cancer treatment Zactima (vandetanib), which shows that the drug in combination with Sanofi-Aventis’ Taxotere (docetaxel) met the primary goal of prolonged progression free survival in non-small cell lung cancer. However statistical significance was not achieved in a trial combining Zactima with Eli Lilly's Alimta (pemetrexed) and another study evaluating the efficacy of vandetanib versus Roche/Genentech’s Tarceva (erlotinib) did not meet the primary objective of demonstrating a statistically significant prolongation of PFS for the AstraZeneca drug.

The company is upbeat about the data as a whole, however, and says that the studies also showed that adding vandetanib to chemotherapy controlled the symptoms of lung cancer better than chemotherapy alone. John Patterson, executive director of development at AstraZeneca, said studies have shown that Zactima can offer clinical benefit to patients with lung cancer “by extending the time a patient can live with their cancer under control, while managing symptoms and maintaining quality of life better than chemotherapy alone”.

AstraZeneca plans to file a regulatory submission in the first half of 2009 and full results from the three Phase III studies – Zodiac, Zeal and Zest – will be presented at a forthcoming international medical congress. Zactima is also currently being investigated in another Phase III monotherapy study in NSCLC and in a number of other cancers, including thyroid cancer.

At 11.10 this morning, UK time, AstraZeneca shares were down 5% to £26.64.