(Adds details, background on drug)
Nov 11 (Reuters) - Britain's GSK said on Friday it will limit the use of its ovarian cancer treatment Zejula in the United States, to patients with some genetic anomalies when given as a second option to keep their cancer at bay.
The drugmaker would restrict the second-line maintenance indication for Zejula to only patients with harmful, or suspected to be harmful, inherited BRCA mutations, at the request of the U.S. Food and Drug Administration (FDA).
The move follows an FDA review of data, which was the basis for approval of the second-line maintenance indication of Zejula, GSK added.
Maintenance therapy involves a drug being used to help keep cancer from recurring and is important for drugmakers as it can significantly boost sales from a longer use of its product.
For GSK, oncology is a key area of focus as a standalone prescription medicine and vaccine business after its split this year. The firm had acquired Zejula with its 2019 multi-billion dollar purchase of Tesaro to rebuild its cancer drug portfolio.
Zejula's U.S. indication for earlier lines of treatment as a first maintenance option in adults in some types of advanced ovarian, fallopian tube or primary peritoneal cancer patients responding to chemotherapy remains unchanged, GSK said.
The therapy belongs to a class of treatments called PARP inhibitors, which work by blocking enzymes involved in repairing damaged DNA, thereby helping kill cancer cells.
A mutation of the BRCA enzyme occurs in about 20% of patients with ovarian cancer. (Reporting by Pushkala Aripaka in Bengaluru; editing by Uttaresh.V)