AstraZeneca has initiated Phase III trials on olaparib in ovarian cancer, representing a turnaround in the prospects of the firm’s PARP inhibitor.

The trials are investigating olaparib in BRCA mutated ovarian cancer patients who are in complete or partial response following platinum-based chemotherapy in the first-line setting (SOLO 1), and in the relapsed setting (SOLO 2). The initiation of these studies is based on the subgroup analysis of a Phase II trial which demonstrated olaparib’s potential in these patients.

As a result of the initiation of this programme, a $285 million charge incurred in December 2011 following the decision not to progress olaparib into Phase III will be reversed in the third quarter of 2013.

Antoine Yver, head of oncology in AstraZeneca’s global medicines development unit, said “we feel olaparib has real potential to significantly improve treatment decisions for this group of patients who currently have limited options, and to become the next important product in our growing oncology portfolio”.

Mutation of the BRCA1 and BRCA2 genes have been linked to hereditary breast and ovarian cancer. Despite advances in treatment and diagnosis, for patients with ovarian cancer that has spread beyond the ovary the five-year survival rate is well below 50%.