Purpose This pilot study developed and evaluated the feasibility, usability, and perceived satisfaction with an end-user mobile medical application and provider web portal. The two interfaces allowed for remote monitoring, provided daily guidance in the management of hypertension and diarrhea, and allowed for rapid management of adverse events during a clinical trial of olaparib and cediranib. Patients and Methods eCO (eCediranib/Olaparib) was designed for patient self-reported, real-time management of hypertension and diarrhea using remote monitoring. eCO links to a Bluetooth-enabled blood pressure (BP) monitor and transmits data to a secure provider web portal. eCO use was assessed for suitability, usability, and satisfaction after 4 weeks using a 17-item questionnaire. Metrics regarding patient-reported BP and diarrhea events were analyzed. Results Sixteen patients enrolled in the pilot. A total of 98.2% of expected BP values were reported: 94.2% via Bluetooth and 5.8% entered manually. Twelve patients experienced 21 BP events (systolic BP > 140 and/or diastolic BP > 90 mmHg on two consecutive readings); data from cycle 1 were comparable to the study database. Thirteen patients reported diarrhea (more than one stool per 24 hours over baseline) categorized as grade 1 or 2, which was comparable to the study database. Survey analysis showed that patients had statistically significant, positive responses to the use of the eCO application. Patients indicated eCO use made them feel more involved in their care and better connected to their health care team. The only aspect of the application that did not show a statistically significant positive response was the process of reporting diarrhea. Conclusion The eCO application was designed to assist in managing acute treatment-related events most often associated with treatment discontinuation, need for drug holidays, or dose interruption. Hypertension and diarrhea events reported via eCO allowed rapid provider response and a positive overall patient experience.