(Reuters) – AstraZeneca said on Wednesday its cancer drug, Lynparza, was successful in helping patients with metastatic prostate cancer and certain genetic mutations live longer without the disease worsening, compared with the standard of care.

The British drugmaker said the treatment met the main goal in a late-stage study of patients with metastatic castration-resistant prostate cancer and BRCA1/2 or ATM gene mutations. Patients were previously treated with hormonal anticancer therapies.

BRCA and ATM genes are responsible for producing proteins that repair damaged DNA, but can cause cancer growth if the genes mutate.

“This will be a big extension to Lynparza’s market potential and will be seen as good news. After good phase II data this trial was expected to work,” Liberum analysts said in a note.

Prostate cancer is the second-most common cancer in men, with an estimated 1.3 million new cases diagnosed worldwide in 2018, AstraZeneca said.

Lynparza, which is being jointly developed with Merck, is already approved for advanced ovarian cancer and metastatic breast cancer. The drug is an important growth driver for the British drugmaker as it builds its cancer treatment portfolio.

The treatment belongs to a class of drugs known as PARP inhibitors, which keep cancer cells damaged by chemotherapy from repairing themselves. Lynparza became the first PARP drug to reach the market with a U.S. approval for ovarian cancer in late 2014.

(Reporting by Pushkala Aripaka in Bengaluru, Editing by Sherry Jacob-Phillips and Anil D’Silva)