April 5 (Reuters) - AstraZeneca ( AZN ) said on Friday

its blockbuster cancer drug Imfinzi helped improve survival in

patients in the early stages of an aggressive type of lung

cancer, making it the first such immunotherapy to meet two key

trial goals.

In a late-stage trial, the drug demonstrated "statistically

significant and clinically meaningful improvement" in both

overall survival and slowing the progression of the cancer in

patients for whom the disease had not worsened following

chemoradiotherapy, according to the Anglo-Swedish drugmaker.

Imfinzi is a human monoclonal antibody which works to block

a tumour's ability to evade and dampen the immune system, while

also boosting the body's anti-cancer immune response, offering

an alternative to toxic chemotherapy.

Small-cell lung cancer is a highly aggressive form of cancer

that typically recurs and progresses rapidly despite initial

response to chemotherapy and radiotherapy, with only 15% to 30%

of patients alive five years after diagnosis.

Imfinzi clocked $4.24 billion in sales in 2023, and is a

blockbuster medicine in AstraZeneca's ( AZN ) key oncology portfolio,

which makes up more than 20% of its total revenues.

The company estimates there are 20,000 patients in the G7

countries in early stages of the disease and given Imfinzi

already has approval in the region for treating later stages of

the cancer, it will be an opportunity to "move rapidly" with

health authorities on securing approval, said AstraZeneca ( AZN )

Executive Vice President of Oncology David Fredrickson.

The U.S. Food and Drug Administration first approved the

drug in 2017 to treat a type of bladder cancer. Imfinzi won

approval for use in mid-stage non-small cell lung cancer a year

later. In March 2020, the FDA approved Imfinzi to target

extensive-stage small-cell lung cancer.