Washington, DC (UroToday.com) In today’s prostate cancer session at the 2015 Society of Urologic Oncology, Dr. Felix Feng from the University of Michigan presented his data og PARP inhibitors in prostate cancer treatment. It is known that 23% of CRPC harbor DNA repair alterations. Single DNA strand damage is repaired by the PARP protein. By inhibiting the protein the damage is not repaired but progresses to double strand damage. Since many cancers harbor DNA repair alterations (e.g. BRCA,
ATM), this damage is not repaired and the cell dies. There are 145 trials on PARP inhibitors in cancer but only 6 on prostate cancer. The TORAP trial examined the efficacy of Olaparib, a PARP inhibitor, in mCRPC. First 30 patients were treated with the drug. Patients who had an intermediate response were examined for the DNA repair alterations and those positive were further treated. Overall response rate after the first part was 32% but 88% of patients with the DNA repair alteration had a durable response. Dr Feng concluded that 20-30% of metastatic CRPC harbor alterations in DNA repair genes. Studies suggest that PARP inhibitors are highly effective in these patients.
University of Michigan
Dr. Miki Haifler, MD. from the Society of Urologic Oncology Meeting - December 2 - 4, 2015 – Washington, DC.
Fox Chase Cancer Center, Philadelphia, PA.