Study Design and Participants

We designed this multicenter, single arm, phase II clinical trial in order to evaluate the maintenance treatment with IL2 and zoledronate after autologous bone marrow transplantation in patients with multiple myeloma. Patients were enrolled in the hematology units of Pisa University Hospital and Parma University Hospital after the signature of a written informed consent. The trial was conducted in accordance with the Declaration of Helsinki and in compliance with good clinical practice. The ethical boards of our institutions approved the protocol that was registered in the clinical trials information network of the Italian national observatory (EUDRACT N° 2013-001188-22).

Patients, aged between 18 and 70 years, with a histologically proven diagnosis of multiple myeloma become eligible if achieved a VGPR in bone marrow samples after 3 months from autologous transplantation, according to international myeloma working group criteria (20). Exclusion criteria include Eastern Cooperative Oncology Group performance status >2, a creatinine clearance <30 ml/min, serum calcium <8 or >12 mg/dl, osteonecrosis of the jaw, ongoing phlogosis of dental roots, and history of autoimmune or bone disorders such as Paget’s disease.