Osteonecrosis of the jaw onset times are based on the route of bisphosphonate therapy

PURPOSE

Osteonecrosis of the jaw (ONJ) has been reported to be associated with patients receiving bisphosphonate (BP) therapy. There are many reports that suggest that the time of exposure to BPs is a significant risk factor for ONJ and that the greatest risk occurs after dentoalveolar surgery. The aim of this study was to retrospectively investigate the duration of BP therapy and related events before the onset of ONJ based on an intravenous (IV) or oral route of administration.

MATERIALS AND METHODS

We conducted a retrospective cohort study of patients referred to our institution to identify the onset of ONJ based on the exposure to BP therapy and associated triggers (ie, dentoalveolar surgery or spontaneous occurrence) based on the route of BP administration. Demographic data (ie, age, gender, and race), medical diagnosis related to BP therapy, and information as to whether the BP therapy was continued at the time of ONJ diagnosis were also collected.

RESULTS

We reviewed the records for 114 patients with a history of ONJ. We divided patient cohorts by route of BP administration, with 76 patients having a history of IV BP therapy and 38 patients having a history of oral BP therapy. The overall onset of ONJ was earlier in the IV BP group (median, 3 years) compared with the oral BP group (median, 5 years). There was no statistical difference in the duration to occurrence of ONJ associated with dental extraction compared with spontaneous occurrence for both the IV and oral BP groups.

CONCLUSIONS

The median onset of ONJ for patients undergoing IV BP therapy occurs earlier than the median onset for patients undergoing oral BP therapy, and there was no difference in onset occurring spontaneously and after dental extraction. The significance of these findings suggests that patients who receive IV BP therapy should be closely evaluated after the initiation of BP therapy. The lack of evidence suggesting greater onset after dental extraction may provide clinical support for dentoalveolar surgery that is indicated for patients with a history of BP therapy. Research focusing on the clinical circumstances and physiologic events during early antiresorptive therapy may provide insight as to the critical risk factors.

Persistency with zoledronic acid is associated with clinical benefit in patients with multiple myeloma

Zoledronic acid (ZOL), an intravenous bisphosphonate, has been shown to reduce and delay the incidence of skeletal-related events (SREs) in multiple myeloma (MM) patients with bone disease. A retrospective claims-based analysis was conducted that used two distinct US managed care databases to examine the relationship between persistency with ZOL and clinical benefit. Patients >18 years, diagnosed with MM, and with at least one claim for ZOL (or a claim for malignant bone disease and ZOL initiation within 30 days) between 1/1/2001 and 12/31/2006 were included. Patients were evaluated for incidence of SREs and for mortality. Treatment persistency was defined as the absence of a >45 day gap between ZOL administrations. Of 1,655 patients in this analysis, 1,060 received ZOL and 595 received no intravenous bisphosphonate therapy. Compared with patients not receiving bisphosphonate therapy, ZOL-treated patients had lower incidences of SREs (P < 0.0001) and death (P = 0.0001). Longer persistency with ZOL was associated with lower risks of SREs (P = 0.001), fracture (P = 0.003), and death (P = 0.002) versus shorter persistency. Patients who were persistent with ZOL for ≥1.5 years had an incidence of 15.0 SREs and 6.2 fractures per 100 person-years. Patients who were persistent for 31-90 days had an incidence of 24.6 SREs and 14.0 fractures per 100 person-years, and patients not receiving intravenous bisphosphonates had an incidence of 32.2 SREs and 16.9 fractures per 100 person-years. These data from a real-world setting indicate that among MM patients, longer persistency with ZOL was associated with a lower risk of SREs and fracture.