It is common knowledge that men with metastatic castration-resistant prostate cancer (CRPC) don’t all have the same disease. There are many different types or flavors of prostate cancer.
These differences are involved in the genetic structure of the cancer cell its self. Some prostate cancers have mutations in the DNA repair genes (genes whose job is to repair other gene mutations). It has been shown that prostate cancer that have these mutations are more likely to respond to the poly(ADP-ribose) polymerase (PARP) inhibitor olaparib. (Currently olaparib is FDA approved for certain types of advanced ovarian cancers.)
In the recently evaluated phase II TOPARP trial, 17 of the 49 evaluable men responded to the investigation drug olaparib. Six of these men had radiologic responses and 11 had biochemical responses, as determined by a reduction in prostate-specific antigen (PSA) levels of greater than 50%. Four of these men had responses that lasted more than 12 months.
Mirroring these results, Joaquin Mateo, MD, a clinical research fellow in the Prostate Targeted Therapy Group and Drug Development Unit at the Institute of Cancer Research an