Chemotherapy can damage nervous system structures leading to chemotherapy-induced peripheral neuropathy (CIPN) which impairs quality of life and daily functioning for millions of cancer survivors. Some 30% of recipients live with CIPN chronically beyond completion of chemotherapy. Conventional care is symptomatic including antidepressants, anticonvulsants, analgesics, vitamin supplements and topical gels to manage symptoms. While there are no FDA-approved treatments, evidence indicates that specific manual therapy techniques can reduce symptoms of CIPN. There is also evidence that caregivers can learn safe and effective manual therapy techniques for use in caregiving through multimedia instruction. However, there currently is no caregiver education product teaching specific techniques and safety precautions pertaining to CIPN. This project will develop a mobile health (mHealth) app to empower caregivers with knowledge, skills, self-efficacy and motivation to support loved ones with CIPN by use of simple manual techniques based on specific understanding and safety precautions for CIPN. The project will use a human-centered design approach in formative research to develop a “minimum viable product (MVP)” for the eventual caregiver mHealth app. A user-centered, iterative process with caregiver focus groups will guide development of the MVP which will then be assessed for feasibility through a Think-Aloud protocol. Specific Aims are as follows: Aim 1. Develop initial user-centered app design. We will develop preliminary requirements for core educational content to be featured in the app, then refine this with patient focus group feedback. The resulting initial app design will incorporate principles of ease of navigation, usability, utility, and engagement. Aim 2. Refine app design through an iterative process of qualitative feedback. The initial app design will be processed and revised through three rounds of caregiver focus groups for qualitative feedback and refinement. Qualitative analysis of responses after each round will be conducted, and applied to produce revised versions through round 3, resulting in the MVP prototype. Aim 3. Evaluate usability of a minimum viable product (MVP). Caregivers will experience the MVP prototype through an interactive Think-Aloud session with the design team that is recorded for qualitative analysis. This will be followed by debriefing with structured interview questions about design, relevance and intent to use. Quantitative data will assess system usability, and perceived relevance and impact on caregiving. Feasibility criteria will be usability scores and user ratings of perceived value and “intent to use” in caregiving. If Phase I is successful the app will be completed in Phase II followed by a large RCT to assess outcomes of use for both CIPN sufferers and caregivers. Eventual public health benefits include improved quality of life and functional well-being for the population of CIPN sufferers, reduced ...