Tumour cells with a mutation that affects their ability to repair severed DNA can be killed with a drug that knocks out a second repair mechanism. That's the finding from a phase I clinical trial that enrolled patients with cancer-associated mutations in the BRCA DNA-repair genes.
Johann de Bono of the Institute of Cancer Research in Sutton, UK, and his co-workers gave patients olaparib, which inhibits an enzyme involved in a second DNA-repair pathway. Out of 19 patients with a BRCA mutation, 12 showed signs of tumour shrinkage or stabilization. (Pictured above: left, a computed tomography scan of the abdomen of one patient with ovarian cancer (circled); and right, showing complete tumour regression after four months of treatment.)
The study shows promise for using cancer molecular biology to devise personalized therapies that exploits a tumour's genetic or molecular defects.