2015 AACR Novel Combination Therapy of SGI-110 and BMN-673 for BRCA-Proficient Ovarian Cancer

Summary

Ovarian cancer (OC) is initially chemoresponsive but the majority of patients relapse after first line platinum-, taxane-based chemotherapy.
Recurrence has been shown to be associated with increased DNA damage response (DDR) mediated by poly-(ADP)-ribose polymerase 1/2 (PARP1/2), which can be therapeutically targeted by PARP inhibitors (PARPi). Although PARPi are indicated for platinum-responsive, BRCA-mutated OC, most OC patients have BRCA-proficient disease.
Based on our previous studies supporting a role for DNA methylation in chemoresistant OC, mediated by the enzyme DNA methyltransferase 1 (DNMT1), and reports on a functional role for DNMT1 in DNA double strand break repair mediated by BRCA1/2, we hypothesize that combining the DNMTi SGI-110 and the PARPi talazoparib (BMN673) will impair BRCA-mediated DDR, resulting in cytotoxicity. CONCLUSION: Combination SGI-110 + talazoparib treatment significantly reduced cancer cell colony formation. Regardless of BRCA and platinum sensitivity status, co-administration of SGI-110 and talazoparib reduced cell survival, albeit %survival was dependent on drug dose and cancer cell line.