Tesaro’s Ovarian Cancer Drug Gets FDA Nod, No Diagnostic Needed

Xconomy Boston — 

An ovarian cancer drug from Tesaro has won FDA approval ahead of schedule, adding a third treatment to a new group of therapies that work by blocking a process that tumors use to repair themselves.

Waltham, MA-based Tesaro (NASDAQ: TSRO) says the FDA approved its drug niraparib (Zejula) drug as a maintenance therapy for women with recurrent ovarian cancer. The approval comes three months early; an FDA decision wasn’t expected until June 30. In approving the drug, the FDA also said that a companion diagnostic to match the treatment to a patient’s genetic profile would not be required. That makes niraparib the first drug in this new class that doesn’t require such a test.

The Tesaro drug is what’s called a called a PARP inhibitor. PARP stands for poly(ADP-ribose) polymerase, which is a type of enzyme that help cancer cells repair damage caused by chemotherapy and other drugs. PARP blockers work by interfering with these enzymes. AstraZeneca (NYSE:AZN) won the first PARP blocker approval from the FDA in 2014 for olaparib (Lynparza). That drug was approved for patients who have mutations on the BRCA gene and have failed multiple treatments of chemotherapy.

Late last year, the FDA approved rucaparib, a PARP blocker developed by Boulder, CO-based Clovis Oncology (NASDAQ: CLVS). Like the AstraZeneca drug, Clovis’s PARP blocker was approved for patients who have BRCA mutations. Both drugs were meant to be used with a companion diagnostic that tested for BRCA gene mutations.

FDA approval of the Tesaro drug is based on a Phase 3 clinical trial that enrolled 533 patients with recurrent ovarian cancer who either had a partial response or a complete response to their most recent chemotherapy treatment. According to Tesaro, two-thirds of the women in the study did not carry BRCA mutations; in those patients, niraparib reduced by 55 percent the risk of death or that their cancer would get worse. In the women who carried the mutations, niraparib reduced the risk of death or cancer progression by 74 percent.

Ovarian cancer is diagnosed in more than 20,000 women in America each year, making it the ninth most common cancer and the fifth leading cause of cancer death, according to Centers for Disease Control and Prevention data. In 2013, the most recent year for which the CDC has data, more than 14,000 women in the United States died from ovarian cancer. Ovarian cancer is the fifth most common cancer for women in Europe, with 65,600 new cases diagnosed in 2012, according to Cancer Research U.K.

With FDA approval now in hand, Tesaro is targeting late April for a U.S. launch of niraparib. Tesaro is also awaiting an approval decision from European regulators.

Photo by Tesaro.