A recent report, published in conjunction with the 45th annual meeting of the American Society for Clinical Oncology (ASCO), suggests that skeletal complications are an important prognostic factor in multiple myeloma patients treated with the drug Zometa (zoledronic acid).

The researchers studied osteonecrosis of the jaw (ONJ), or death of bone tissue in the jaw, which is a common side effect of Zometa. They found that the development of ONJ was associated with a reduced risk of skeletal-related events, such as bone pain and fracture, and increased overall survival.

The retrospective study examined 300 myeloma patients who were treated with Zometa. The drug is commonly incorporated into therapy regimens for myeloma patients as a supportive treatment to prevent skeletal fractures.

Zometa can cause mild side effects like fatigue and muscle aches as well as serious side effects like ONJ. ONJ develops from a decreased blood supply to the jawbone that can lead to tissue death.

The side effect is commonly observed in patients treated with intravenous bisphosphonates like Zometa, but can be prevented and managed. A previous article on preventative measures for ONJ in Zometa-treated patients can be found here.

Though side effects are well reported for Zometa, patient outcomes or prognostic factors in regard to side effects of the drug have not been well studied. This led the authors to examine the relation of ONJ to patient outcomes and prognosis.

The researchers found that 4.7 percent of patients who were treated with Zometa for nine to 96 months developed ONJ. They also noticed an increased risk for the side effect in diabetic patients.

Of the 14 patients diagnosed with ONJ, 13 remain alive and are currently either in remission or with stable disease. Only one patient diagnosed with ONJ in the study died.

Patients with ONJ were studied for four to 49 months after diagnosis. Of the 14 patients, two showed a worsening of the condition, five were stable, and seven saw an improvement or resolved disease. Overall, patients with ONJ showed improved overall survival in a time-dependant analysis.

The overall skeletal morbidity rate, which is the ratio of skeletal-related events per year, was 0.16, meaning less than one skeletal-related event was experienced per year. The researchers also point out that patients with ONJ had a lower skeletal morbidity rate than those who did not develop ONJ.

For more information, please see abstract e19519 at the 2009 ASCO meeting Web site.