In dose escalation, patients will receive irinotecan and rucaparib. Irinotecan will be given once every 2 weeks (or 3 weeks if not tolerated) and rucaparib will be given twice daily for 7-14 days. Each cycle will be 28 days in duration unless we need to switch to the intermediate dosing regimen of every 21 days. Both rucaparib and irinotecan will be escalated.