AstraZeneca plc (AZN) - Get Report shares rose sharply in early trading Monday after the drugmaker said a study of its key lung cancer treatment showed stronger-than-expected results in patients whom had not progressed following chemotherapy

The U.K. drugmaker said its Imfinzi (durvalumab) oncology drug, which treats locally-advanced, unresectable non-small cell lung cancer (NSCLC), improves the progression-free survival rate of patients by more than 11 months in a presentation to the European Society of Medical Oncology Congress in Madrid.

"The Phase III PACIFIC results are incredibly encouraging for a patient population that until now has been without treatment options. As the first Immuno-Oncology medicine to achieve improvement in progression-free survival in this setting, Imfinzi is showing clear potential to become a new standard of care for patients with locally-advanced, unresectable NSCLC who have not progressed following chemoradiation."

AstraZeneca shares were marked 1.9% higher in the opening minutes of London trading to change hands at 4,872 pence each, the highest since July 27, when the shares plunged 15.4% after the company told investors that Imfinzi had failed to show an improvement in progression free survival for first line lung cancer when administered as a combination with tremelimumab.

The failure, which came closely on the heels of speculation that CEO Pascal Soriot had decided to leave for a new role, was meaningful for Astra because oncology is the cornerstone of the drugmaker's attempt to move on from a series of key patent expirations that have been a source of concern for investors in recent years.

Soriot later challenged that speculation by presenting the company's second quarter earnings on July 27 and telling staff in an internal memo that "Together, we are poised to achieve something remarkable and that few thought possible. Nothing can break the momentum you have established, and certainly not rumors." 

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