OBJECTIVE: To pilot test a mobile health intervention using a CONnected CUstomized Treatment Platform that integrates a connected electronic adherence monitoring smartbox and an early warning system of non-adherence with bidirectional automated texting feature and provider alerts. METHODS: In total, 29 adult women with hormone-receptor-positive, human epidermal growth factor receptor 2-negative metastatic breast cancer and a prescription for palbociclib were asked to complete a survey and participate in a CONnected CUstomized Treatment Platform intervention, including use of a smartbox for real-time adherence monitoring, which triggered text message reminders for any missed or extra dose, and referrals to (a) participants oncology provider after three missed doses or an episode of over-adherence, or (b) a financial navigation program for any cost-related missed dose. Use of smartbox, number of referrals, palbociclib adherence, CONnected CUstomized Treatment Platform usability measured by System Usability Scale, and changes in symptom burden and quality of life were assessed. RESULTS: Mean age was 57.6 and 69% were white. The smartbox was used by 72.4% of participants, with palbociclib adherence rate of 95.8%±7.6%. One participant was referred to oncology provider due to missed doses and one was referred to financial navigation. At baseline, 33.3% reported at least one adherence barrier including inconvenience to get prescription filled, forgetfulness, cost, and side effects. There were no changes in self-reported adherence, symptom burden or quality of life over 3 months. CONnected CUstomized Treatment Platform usability score was 61.9 ± 14.2. CONCLUSION: The CONnected CUstomized Treatment Platform interventions is feasible, resulting in a high palbociclib adherence rate without any decline in overtime. Future efforts should focus on improving usability.