The approval will allow the use of Imfinzi to treat patients with extensive-stage small cell lung cancer (ES-SCLC).

The approval by the European Commission was based on positive results from a late-stage study in which Imfinzi plus chemotherapy showed a statistically significant improvement in overall survival of patients with ES-SCLC, AstraZeneca said.

AstraZeneca has already carved out a niche for Imfinzi, which enables the immune system to detect and attack certain cancer cells, in the more common non-small cell lung cancer (NSCLC) types, with approval for tumours that have only spread in the chest.

In small-cell cancer treatments, Astra is seeking to catch up with Roche, whose immunotherapy Tecentriq won U.S. approval for the disease type a year ago.

Lung cancer is the leading cause of cancer deaths among both men and women, accounting for about a fifth of all deaths from the disease.

(Reporting by Aakash Jagadeesh Babu in Bengaluru; Editing by Saumyadeb Chakrabarty)