In this trial, olaparib will be delivered alone for 14 days with the hypothesis that priming of the apoptotic machinery will be required prior to introduction of the senolytic agent (navitoclax). To date navitoclax and olaparib have not been combined in the clinic. The Phase I study will therefore be conducted to define the recommended Phase II dose (RP2D). A plan for a future Phase II study will depend on the results obtained during this Phase I trial. Based on the potential for overlapping toxicity (particularly hematologic toxicity) an interrupted dosing schedule will be used for the navitoclax. Based on preclinical studies it is believed that intermittent delivery of the senolytic agent is in line with the proposed mechanism of action. Subsequently the dose of navitoclax will be escalated with a fixed dose of olaparib in 28-day cycles.