FDA Staff Questions Benefit of Astra/Zeneca Ovarian Cancer Drug

Staff reviewers at the U.S. Food and Drug Administration (FDA) said AstraZeneca’s experimental ovarian cancer drug olaparib showed an 83 percent reduction in the risk of disease progression but they questioned whether the result could be reproduced.

The drug, olaparib, is designed as a maintenance treatment for some women with relapsed ovarian cancer whose tumors are responding completely or in part to platinum-based chemotherapy, Reuters reports. The drug maker says that only 15 percent of ovarian cancers are found before the cancer has spread outside the ovary, and for patients whose ovarian cancer has spread beyond the ovary the five-year survival rate is well below 50 percent.

Olaparib blocks the activity of Poly (ADP-ribose) polymerase (PARP), an enzyme that plays a key role in cell repair. The drug is aimed at women with a BRCA gene mutation, according to Reuters. Patients in a clinical trial had a seven-month median improvement in progression-free survival.

The staff report was released on the FDA’s website on Monday two days before a meeting of outside experts who will discuss whether the drug’s benefits outweigh its risks and whether further data is needed before approval. The FDA staff review questions whether AstraZeneca’s conclusions could have been skewed by a very small group of patients delivering signs of a false benefit due to an “underperforming” control arm in the study, according to FierceBiotech. Given the drug’s potential side effects, the FDA wants the outside panel to consider whether AstraZeneca should wait for more definitive data before marketing the drug.