Sept 17 (Reuters) - Daiichi Sankyo ( DSKYF ) and Merck ( MRK )

said on Tuesday that their drug, patritumab deruxtecan,

met the main goal in a late-stage study in some patients with a

type of lung cancer.

The drug helped patients live significantly longer

without their cancer progressing, compared with patients who

were treated with chemotherapy, the companies said.

The drug belongs to a class of treatments called

antibody-drug conjugates, which have often been described as

"guided-missile" cancer drugs.

Patritumab deruxtecan was tested in patients with

non-small cell lung cancer who had a gene mutation called EGFR.

Non-small cell lung cancer is the most common form of lung

cancer.

The study focused on patients who had previously

received treatment with a class of drugs known as tyrosine

kinase inhibitors.