Osteonecrosis of the Jaw in Patients Transitioning from Bisphosphonates to Denosumab Treatment for Osteoporosis

Antiresorptive-related osteonecrosis of the jaw (ARONJ) is a rare but severe side effect of antiresorptive treatment with bisphosphonates or RANKL-antibody denosumab in patients with malignant diseases or osteoporosis. Whilst osteonecrosis of the jaw (ONJ) related to the administration of bisphosphonates (BPs) has been investigated for more than 1 decade now, only few data are available on denosumab-related ONJ, especially in patients with osteoporosis. From 2008 to 2016, 52 osteoporosis patients were treated with ARONJ in the Department of Oral and Maxillofacial Surgery, University Medical Center Freiburg, Germany. In all patients, a surgical regimen consisting of complete removal of necrotic bone, primary wound closure and perioperative i.v. antibiotic therapy was applied. Of the 52 patients, 38 developed ARONJ after BP monotherapy; in 11 patients, antiresorptive therapy had been transitioned from BPs to denosumab and 3 patients had received denosumab monotherapy. From July 2013, when the first patient with ONJ and transitioning therapy from BPs to denosumab presented to our department, to October 2016, we found recurrences in 17.6% of the patients with BP monotherapy and in 45.5% of the patients with transitioning therapy from BPs to denosumab. Transitioning antiresorptive therapy from BPs to denosumab may be an additional risk factor for developing ARONJ. In these patients, treatment of ARONJ-lesions seems to provoke more complications. An additional dental screening before transitioning should be initiated. Further studies are needed to evaluate if a first-line treatment with denosumab decreases the incidence of ARONJ in patients with osteoporosis and simplifies its treatment.