(Reuters) – The U.S. Food and Drug Administration approved AstraZeneca Plc and Merck & Co Inc’s Lynparza as a treatment for a form of prostate cancer, the companies said in a joint statement on Wednesday.

The drug approval by the U.S. regulator is for treating patients with a form of prostate cancer that could not be held back by standard hormone therapy.

The approval was based on results from a late-stage study where the drug reduced the risk of disease progression or death by 66% when compared with hormonal anticancer therapies such as enzalutamide or abiraterone.

Lynparza leads a class of drugs known as PARP inhibitors, which keep cancer cells damaged by chemotherapy from repairing themselves, and is a key asset for AstraZeneca with approvals in ovarian, breast and pancreatic cancers.

The latest approval for the blockbuster cancer drug comes just weeks after it won broader approval as a treatment for ovarian caner in the United States.

Prostate cancer is the second most common cancer in men, with more than 191,000 new diagnoses expected in the United States in 2020, according to the American Cancer Society.

(Reporting by Aakash Jagadeesh Babu in Bengaluru; editing by Uttaresh.V and Rashmi Aich)