AstraZeneca has signed up Foundation Medicine to develop a novel companion diagnostic assay for its cancer drug Lynparza that will enable doctors to identify patients most likely to benefit from treatment.

Lynparza (olaparib) is a first-in-class poly ADP-ribose polymerase (PARP) inhibitor designed to exploit tumour DNA repair pathway deficiencies to preferentially kill cancer cells.

The drug is currently approved in the US for the treatment of germline BRCA-mutated advanced ovarian cancer and in the EU for patients with platinum-sensitive relapsed BRCA-mutated high-grade serous epithelial ovarian, fallopian tube or primary peritoneal cancer.

According to Nina Mojas, global medicine lead for Lynparza at AZ, the agreement for a diagnostic test "supports the broad development programme" for the drug. "Utilising Foundation Medicine's leading capabilities in molecular information will help our work to assess the potential of the medicine to address unmet patient need across a number of cancers driven by DNA repair deficiencies, including and - significantly - beyond the BRCA mutations."

The assay, which will detect multiple classes of genomic alterations across a range of genes involved in Homologous Recombination Repair (HRR), will be developed as part of a coordinated drug-diagnostic regulatory strategy, the firm noted.

Survival benefit
Meanwhile, over at the American Society of Clinical Oncology meeting, AZ has presented results from a third interim analysis of Study 19 suggesting that an improvement in overall survival (OS) for patients with ovarian cancer treated with Lynparza maintenance therapy following platinum-based chemotherapy.
A 27 percent reduction in the risk of death compared to placebo was seen in the overall trial population (median OS 29·8 versus 27·8 months), with greater reduction in the risk of death of 38 percent compared to placebo observed in patients with BRCA1/2 mutations (BRCAm).

Also, a number of patients continue to benefit from Lynparza maintenance therapy, with 15 percent of BRCAm patients receiving the drug for over five years, "which is significant for patients with limited treatment options," noted lead author Jonathan Ledermann, director of the Cancer Research UK & UCL Cancer Trials Centre.

The update supports previously presented results showing a significant improvement on progression-free survival (PFS) over placebo, with the greatest effect seen in the BRCAm subgroup, and a significant improvement in time to first subsequent therapy or death.