Improvements in health care are extending the life expectancy of cancer patients, up to the point that cancer survivors are sometimes considered as chronic patients. Mobile devices may support outpatients in managing chronic diseases, improving their quality of life and reducing health-care costs. This paper illustrates the design and implementation of a pair of mobile apps supporting patients and General Practitioners (GPs) in the management of Multiple Myeloma (MM). The patient app supports him in distinguishing the conditions that anticipate MM worsening from those arising as a side effect of the therapy or from those unrelated to the disease. The app for GPs helps them in properly applying standard practices for prescribing lab tests, radiological investigations, or referring to the hematologist. The goal is to reduce the number of accesses to the hematologists, emphasizing the central role of the GP. A randomized controlled trial is planned later this year to assess the reduction in visits.